US20030129372A1 - Thin films of crosslinked fluoropolymer on a carbon substrate - Google Patents
Thin films of crosslinked fluoropolymer on a carbon substrate Download PDFInfo
- Publication number
- US20030129372A1 US20030129372A1 US09/323,510 US32351099A US2003129372A1 US 20030129372 A1 US20030129372 A1 US 20030129372A1 US 32351099 A US32351099 A US 32351099A US 2003129372 A1 US2003129372 A1 US 2003129372A1
- Authority
- US
- United States
- Prior art keywords
- layer
- carbon layer
- carbon
- thickness
- crosslinked
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 109
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 108
- 239000000758 substrate Substances 0.000 title claims abstract description 63
- 229920002313 fluoropolymer Polymers 0.000 title claims abstract description 45
- 239000004811 fluoropolymer Substances 0.000 title claims abstract description 40
- 239000010409 thin film Substances 0.000 title 1
- 239000010702 perfluoropolyether Substances 0.000 claims abstract description 22
- 229920006037 cross link polymer Polymers 0.000 claims abstract description 21
- 239000000463 material Substances 0.000 claims abstract description 16
- 238000003860 storage Methods 0.000 claims description 36
- 239000003575 carbonaceous material Substances 0.000 claims description 3
- 229910000531 Co alloy Inorganic materials 0.000 claims description 2
- 229910003481 amorphous carbon Inorganic materials 0.000 claims 1
- 239000000314 lubricant Substances 0.000 abstract description 68
- 238000004132 cross linking Methods 0.000 abstract description 31
- 238000013500 data storage Methods 0.000 abstract description 14
- 230000001678 irradiating effect Effects 0.000 abstract description 2
- 239000010410 layer Substances 0.000 description 140
- 230000005855 radiation Effects 0.000 description 24
- 238000000576 coating method Methods 0.000 description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 20
- 239000011248 coating agent Substances 0.000 description 14
- 238000005260 corrosion Methods 0.000 description 14
- 230000007797 corrosion Effects 0.000 description 14
- 229920000642 polymer Polymers 0.000 description 14
- 238000000034 method Methods 0.000 description 12
- 230000001681 protective effect Effects 0.000 description 12
- 239000007787 solid Substances 0.000 description 11
- 238000013459 approach Methods 0.000 description 9
- 230000008569 process Effects 0.000 description 9
- 238000005461 lubrication Methods 0.000 description 8
- 229920000570 polyether Polymers 0.000 description 8
- 238000004544 sputter deposition Methods 0.000 description 8
- 239000000696 magnetic material Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 6
- 125000006850 spacer group Chemical group 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 238000005530 etching Methods 0.000 description 4
- 238000005286 illumination Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 3
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- 238000000429 assembly Methods 0.000 description 3
- 230000000712 assembly Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000875 corresponding effect Effects 0.000 description 3
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical compound FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 description 3
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 3
- 229910052753 mercury Inorganic materials 0.000 description 3
- 230000005012 migration Effects 0.000 description 3
- 238000013508 migration Methods 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 206010073306 Exposure to radiation Diseases 0.000 description 2
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 2
- 241000511976 Hoya Species 0.000 description 2
- 229910018104 Ni-P Inorganic materials 0.000 description 2
- 229910018536 Ni—P Inorganic materials 0.000 description 2
- 239000004721 Polyphenylene oxide Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000005238 degreasing Methods 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- -1 for example Chemical class 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 230000002209 hydrophobic effect Effects 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 239000010687 lubricating oil Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000011253 protective coating Substances 0.000 description 2
- 239000011241 protective layer Substances 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 238000009987 spinning Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- AJDIZQLSFPQPEY-UHFFFAOYSA-N 1,1,2-Trichlorotrifluoroethane Chemical compound FC(F)(Cl)C(F)(Cl)Cl AJDIZQLSFPQPEY-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910020630 Co Ni Inorganic materials 0.000 description 1
- 229910002440 Co–Ni Inorganic materials 0.000 description 1
- 229910020707 Co—Pt Inorganic materials 0.000 description 1
- 206010052805 Drug tolerance decreased Diseases 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910018487 Ni—Cr Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 229910000323 aluminium silicate Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- 150000002009 diols Chemical group 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 239000012948 isocyanate Substances 0.000 description 1
- 150000002513 isocyanates Chemical group 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229960004624 perflexane Drugs 0.000 description 1
- ZJIJAJXFLBMLCK-UHFFFAOYSA-N perfluorohexane Chemical compound FC(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F ZJIJAJXFLBMLCK-UHFFFAOYSA-N 0.000 description 1
- YVBBRRALBYAZBM-UHFFFAOYSA-N perfluorooctane Chemical compound FC(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F YVBBRRALBYAZBM-UHFFFAOYSA-N 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 238000005240 physical vapour deposition Methods 0.000 description 1
- 229960005235 piperonyl butoxide Drugs 0.000 description 1
- 125000004591 piperonyl group Chemical group C(C1=CC=2OCOC2C=C1)* 0.000 description 1
- 238000007750 plasma spraying Methods 0.000 description 1
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 230000036316 preload Effects 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 239000011232 storage material Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 125000000876 trifluoromethoxy group Chemical group FC(F)(F)O* 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/739—Magnetic recording media substrates
- G11B5/73911—Inorganic substrates
- G11B5/73921—Glass or ceramic substrates
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/64—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent
- G11B5/65—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition
- G11B5/656—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition containing Co
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/72—Protective coatings, e.g. anti-static or antifriction
- G11B5/725—Protective coatings, e.g. anti-static or antifriction containing a lubricant, e.g. organic compounds
- G11B5/7253—Fluorocarbon lubricant
- G11B5/7257—Perfluoropolyether lubricant
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/72—Protective coatings, e.g. anti-static or antifriction
- G11B5/726—Two or more protective coatings
- G11B5/7262—Inorganic protective coating
- G11B5/7264—Inorganic carbon protective coating, e.g. graphite, diamond like carbon or doped carbon
- G11B5/7266—Inorganic carbon protective coating, e.g. graphite, diamond like carbon or doped carbon comprising a lubricant over the inorganic carbon coating
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/739—Magnetic recording media substrates
- G11B5/73911—Inorganic substrates
- G11B5/73917—Metallic substrates, i.e. elemental metal or metal alloy substrates
- G11B5/73919—Aluminium or titanium elemental or alloy substrates
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/739—Magnetic recording media substrates
- G11B5/73923—Organic polymer substrates
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S428/00—Stock material or miscellaneous articles
- Y10S428/90—Magnetic feature
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24942—Structurally defined web or sheet [e.g., overall dimension, etc.] including components having same physical characteristic in differing degree
- Y10T428/2495—Thickness [relative or absolute]
- Y10T428/24967—Absolute thicknesses specified
- Y10T428/24975—No layer or component greater than 5 mils thick
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
- Y10T428/263—Coating layer not in excess of 5 mils thick or equivalent
- Y10T428/264—Up to 3 mils
- Y10T428/265—1 mil or less
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/30—Self-sustaining carbon mass or layer with impregnant or other layer
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/3154—Of fluorinated addition polymer from unsaturated monomers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/3154—Of fluorinated addition polymer from unsaturated monomers
- Y10T428/31544—Addition polymer is perhalogenated
Definitions
- the invention relates to films of crosslinked fluoropolymer that serve as lubrication and/or protection coatings.
- the invention more particularly relates to magnetic storage media having a crosslinked fluoropolymer lubricant layer.
- Data storage discs for the electronic storage of information are a device of particular interest.
- Disc drives for data storage can use one or more data storage discs with a magnetic medium for the storage of information.
- the magnetic medium generally is formed by a relatively thin magnetic layer on a non-magnetic substrate.
- the data is stored at specific locations along concentric data tracks.
- the disc drive assemblies for magnetic data storage include head/gimbal assemblies aligned with the disc surface.
- the head/gimbal assemblies support transducers, such as magnetoresistive elements, for reading data from and/or writing data to the data tracks near the disc surface.
- the read/write head generally includes an air bearing surface, which faces the disc surface. As the disc rotates, the disc drags air along the air bearing surface. As the air passes along the air bearing surface, the air pressure between the disc surface and the air bearing surface creates a hydrodynamic lifting force that causes the slider or head to deflect away from the disc surface. Prior to rotation of the disc, the slider rests on the disc surface. The hydrodynamic lift is affected by the speed of rotation of the disc, the design of the air bearing surface of the read/write head, and the preload force supplied to the head by the gimbal assembly.
- Discs can include separate landing zones and data storage zones on the disc surface. Information is stored in the magnetic media within the data storage zones.
- the landing zones are used to support the slider when the disc is not rotating.
- the landing zones also provide a takeoff and landing surface for the read/write head.
- the landing zone portion of the disc surface preferably is not used for data storage since repeated contact with the read/write head can destroy stored data in the magnetic medium near the disc surface.
- fly heights between the read/write head and the disc surface are being reduced. Reducing the fly height improves the magnetic interaction between the head and the disc surface to allow correspondingly higher storage densities.
- the disc surface is sufficiently smooth for a particular fly height to reduce contacts between the read/write head and the disc surface. Contact between the read/write head and the disc surface can result in data loss and damage to the disc and/or the head.
- overcoats can be placed on the disc surface over the magnetic medium. Preferred overcoats reduce wear and friction while maintaining proper hydrodynamic interaction between the head and the disc surface during rotation and during take-off and landing.
- Carbon coatings have been used to form protective layers on magnetic substrates.
- the coating increases the spacing between the surface and the underlying substrate.
- any performance improvement resulting from a reduction in fly height can be countered by the presence of protective coatings and the like that result in an increased distance of the magnetic medium and the disc surface.
- lubricant layers generally are used on magnetic disc surfaces to reduce wear and to decrease friction between the disc surface and the head.
- Perfluoropolyethers can be used to form the lubricant layer.
- a variety of approaches have been explored to secure the lubricant layer to the substrate such that the lubricant layer remains on the disc surface for a longer period of time.
- the invention pertains to a magnetic storage medium comprising:
- a first protection means for protecting a magnetic substrate comprising a carbon material
- a second protection means for protecting a magnetic substrate comprising a crosslinked fluoropolymer.
- the invention pertains to a material comprising a magnetic substrate, a carbon layer covering at least a portion of the substrate and a crosslinked fluoropolymer layer covering at least a portion of a surface of the carbon layer, the crosslinked polymer layer having a thickness less than about 40 angstroms and the carbon layer having a thickness of less than about 100 angstroms.
- the invention pertains to a material comprising a magnetic substrate, a carbon layer covering at least a portion of the substrate and a crosslinked fluoropolymer layer covering at least a portion of a surface of the carbon layer, wherein the crosslinked fluoropolymer layer has a thickness at one point on the carbon layer greater by at least about 5 angstroms than the thickness at another point on the carbon layer.
- the invention pertains to a method of forming a lubrication layer of crosslinked fluoropolymer on a carbon substrate, the method comprising irradiating selected portions of the substrate with appropriate amounts of radiation to form a crosslinked fluoropolyer layer with different thicknesses of crosslinked polymer at different locations on the substrate.
- FIG. 1 is a schematic, perspective view of a substrate with a thin carbon coating.
- FIG. 2 is a sectional side view of the substrate with a thin carbon coating of FIG. 1.
- FIG. 3 is a perspective view of a magnetic storage disc with a thin carbon coating.
- FIG. 4 is a sectional side view of an embodiment of a magnetic storage disc.
- FIG. 5 is a schematic, top view of a disc drive system.
- FIG. 6 is a histogram plotting the water contact angle for two different perfluoropolyethers at three different ultraviolet irradiation times.
- FIG. 7 is a plot of total and crosslinked lubricant thickness as a function of ultraviolet irradiation time for two different perfluoropolyethers.
- FIG. 8 is a histogram plotting water contact angle as a function of ultraviolet irradiation time for a hydroxyl terminated perfluoropolyether.
- FIG. 9 is a plot of bonded polymer lubricant as a function of ultraviolet irradiation time for a hydroxyl terminated perfluoropolyether with three different initial thicknesses.
- FIG. 10 is a histogram plotting water contact angle for two different hydroxyl terminated perfluoro polyethers with and without ultraviolet irradiation and with two different initial polymer thicknesses.
- FIG. 11 is a histogram plotting lubricant thickness for two different hydroxyl terminated perfluoro polyethers with and without ultraviolet irradiation and with two different initial polymer thicknesses.
- Crosslinked fluoropolymer lubricant layers formed over a protective carbon layer provide protection against corrosion and wear in a synergistic fashion such that overall thickness of the protective coatings can be decreased.
- a significantly thinner protective carbon layer can be used without diminishing the collective corrosion protection to unacceptable values.
- a layer of crosslinked fluorinated polyether becomes bonded to the protective carbon layer during the crosslinking process.
- Radiation preferably ultraviolet radiation, is used to crosslink the polymer adjacent to the carbon substrate.
- the thickness of the crosslinked portion of the lubricant layer can be adjusted by varying the length of time that the polymer is exposed to crosslinking radiation. The radiation can be directed during the crosslinking process to selected portions of the substrate to vary the crosslinked polymer thickness at different points along the carbon surface.
- Preferred structures include a lubricant layer over a carbon layer as protective layers that are applied to an underlying material.
- the carbon layer is applied over a magnetic medium that is used for magnetic data storage.
- magnetic discs for electronic data storage have a magnetic layer used for data storage that can be coated with a protective carbon layer.
- a read/write head or the like flies adjacent the disc surface when the disc is spinning. The head travels at a very small separation from the disc surface such that a lubricant layer improves performance at the head-disc interface.
- the lubricant layer is relatively thin, such that the distance between the head and the magnetic layers are not increased too significantly due to the presence of the lubrication layer. Also, because of the sealing property of a crosslinked fluoropolymer lubricant layer, a thinner carbon layer can be used than would be acceptable without the lubricant layer. Without the synergistic protection provided by the combination of the thin carbon layer and the crosslinked fluoropolymer, a carbon layer thinner than 100 angstroms does not provide sufficient protection against corrosion in the form of oxidation and cobalt migration. Thus, a crosslinked fluorocarbon layer can be used effectively with a carbon layer having a thickness less than 100 angstroms while providing adequate corrosion protection to a magnetic material under the carbon layer.
- the lubricant layer serves to decrease friction between a head and the disc, to provide some additional protection against impact and to seal the surface to inhibit corrosion of underlying magnetic layers by water coming into contact with the surface.
- Fluorine containing polyethers are particularly preferred in the lubricant layer due to their hydrophobic character.
- Preferred compounds for forming the lubrication layer include perfluoropolyethers and hydrofluoropolyethers.
- AMU atomic mass units
- the Fomblin® unsubstituted perfluoropolyethers made by Montedison (Ausimont) S.P.A., Milan, Italy have molecular formulas of CF 3 O(CF 2 CF 2 O) n (CF 2 O) m CF 3 , where n and m vary to yield particular products with average molecular weights of specified values.
- Suitable fluorinated polyethers include perfluoropolyethers with functional end groups.
- Suitable difunctional perfluoropolyethers include, for example, Fomblin® Z-DOL (hydroxyl end groups), Fomblin® AM2001 (piperonyl end groups), and Fomblin® Z-DISOC (isocyanate end groups).
- Fluorinated polymers with functional end groups may bind to a carbon substrate without the need for crosslinking radiation.
- Other suitable perfluoropolyethers are available under the tradenames Demnum® from Daikin Kogyo Co., Japan and Krytox® from DuPont, Wilmington, Del., having a basic molecular formula of F(CF 2 CF 2 CF 2 ) n CF 2 CF 3 .
- Preferred unsubstituted fluorinated polyethers have average molecular weights less than about 100,000 AMU, preferably less than about 25,000 and more preferably from about 6000 AMU to about 15,000 AMU.
- Preferred fluorinated polyethers with functional end groups have average molecular weights less than about 10,000 AMU, preferably less than about 8,000 AMU and more preferably from about 1000 AMU to about 6,000 AMU.
- the fluorinated polyethers bind to the carbon layer to form a lubricant layer that does not migrate from the carbon layer.
- the inhibition of migration is particularly significant with magnetic disc applications where the spinning of the disc tends to remove fluid lubricants over time.
- Crosslinking within the fluorinated polyether polymers forms a solid layer of lubricant material extending from the carbon surface. Crosslinking increases the hydrophobicity of the lubrication layer, as evidenced by a corresponding increase in the water contact angle of water on the surface, as described further below.
- the crosslinking of the lubricant layer is performed with radiation, preferably ultraviolet light. Exposure to radiation induces the bonding of the lubricant compositions to the carbon layer. Further exposure to the crosslinking radiation results in a solid lubricant composition bonded adjacent to the carbon layer. The thickness of the resulting solid lubricant layer can be selected by the exposure time and radiation intensity. A liquid lubricant layer may remain over the solid lubricant, if sufficient radiation is not applied to crosslink the entire thickness of lubrication material. If desired, any remaining liquid lubricant can be removed with a solvent wash.
- the radiation is applied only to selected regions of the surface.
- the bonding to the carbon layer and the formation of the solid lubrication layer are only formed over the regions of the substrate exposed to the crosslinking radiation.
- different regions of the substrate can be exposed to different amounts of radiation to vary the thickness of the corresponding solid, crosslinked polymer lubricant.
- the application of the radiation to selected portions of the substrate can be accomplished by blocking radiation from striking portions of the substrate or by the use of a focused radiation source, such as a ultraviolet laser, so that radiation is directed only to selected portions of the substrate.
- an article 100 includes a substrate 102 , a carbon layer 104 and a lubricant layer 106 .
- a cross section of article 100 is shown in FIG. 2.
- Protective carbon layer 104 is located on substrate 102 below a lubricant layer 106 , which preferably includes a crosslinked fluoropolyer such as a crosslinked fluorinated polyether.
- Substrate 102 can be any material that will support the deposition of a carbon film. Generally, substrate 102 contributes functional properties to the device. The surface of substrate 102 is protected by carbon layer 104 . Substrate material 102 can itself be a layer on a further support material. For example, if the object is a magnetic disc, substrate 102 generally includes a layer of magnetic material for data storage, as described further below.
- lubricant layer 106 is located at the surface of a magnetic storage disc.
- a lubricant layer 140 is located at a surface of a magnetic storage disc 142 .
- Lubricant layer 140 provides protection against abrasion and the like for a magnetic data storage material.
- Magnetic storage disc 142 can have any reasonable structure consistent with lubricant layer 140 providing a suitable interface for magnetic storage disc 142 .
- a cross section of a preferred embodiment of a magnetic storage disc 150 is shown in FIG. 4.
- a substrate 152 forms the foundation or support structure for storage disc 150 .
- the substrate 152 can be formed from aluminum, aluminum alloy, glass, polymer or other stable non-magnetic material or materials. Aluminum substrates can be plated with Ni—P or the like prior to application of additional layers.
- Substrate 152 can include multiple layers, if desired.
- a magnetic layer 154 is located on substrate 152 . Magnetic layer 154 is used for data storage on disc 150 .
- Magnetic layer 154 can be formed from a variety of magnetic materials, such as cobalt-based alloys or compounds including, for example, Co—Ni, Co—Cr, Co—Ni—Cr, Co—Pt, Co—Ni—Pt, Co—Cr—Ta, Co—Cr—Pt, Co—Cr—Ni—B, Co—P, Co—Ni—P, other similar materials and mixtures thereof.
- cobalt-based alloys or compounds including, for example, Co—Ni, Co—Cr, Co—Ni—Cr, Co—Pt, Co—Ni—Pt, Co—Cr—Ta, Co—Cr—Pt, Co—Cr—Ni—B, Co—P, Co—Ni—P, other similar materials and mixtures thereof.
- a protective carbon layer 156 is located on the magnetic layer 154 , opposite substrate 152 .
- An, optional spacer layer 158 and a lubricant layer 160 are located adjacent protective carbon layer 154 .
- Optional spacer layer 158 preferably is formed from a non-magnetic material and is located between protective carbon layer 156 and magnetic layer 154 . Suitable materials for spacer layer 158 include, for example, silicon, germanium, tin, titanium, molybdenum and tungsten. Spacer layer 158 preferably has a thickness from about 1 nm to about 7 nm. Spacer layer 158 can be formed by sputtering or other similar vapor phase deposition approaches. The use of a spacer layer is described further in U.S. Pat. No. 5,871,841, entitled “Magnetic Disk Medium,” incorporated herein by reference.
- Lubricant layer 160 is used to form a more preferred hydrodynamic interface between a read/write head and magnetic storage disc 150 . Following crosslinking, lubricant layer 160 generally is chemically bonded to carbon layer 154 . Lubricant layer 160 includes a crosslinked portion 162 . Optionally, lubricant layer 160 can include an uncrosslinked portion 164 . Uncrosslinked lubricant can be removed as described below. While crosslinked portion 162 and uncrosslinked portion 164 are depicted as distinct layers marked with a dashed line in FIG. 4, the layers may not be clearly physically separated due to interpenetration of the layers.
- FIG. 5 depicts an embodiment of a disc drive system 200 including drive unit 202 , actuator assembly 204 and controller 206 .
- Drive unit 202 includes disc 208 and spindle 210 connected to a spindle motor.
- actuator assembly 204 includes actuator 212 , support arm 214 , load beam 216 and gimble/head assembly 218 .
- Actuator 212 controls the position of gimble/head assembly 218 over disc 208 by rotating or laterally moving support arm 214 .
- Load beam 216 is located at the end of support arm 214 and gimble/head assembly 218 is located at the end of load beam 216 .
- Controller 206 instructs actuator 212 regarding the position of support arm 214 over disc 208 and drive unit 202 regarding the control of the spindle motor.
- the carbon layer and lubricant layer form a protective overcoat for an underlying substrate, such as a magnetic material.
- the carbon layer is less than about 100 Angstroms thick, preferably less than about 80 Angstroms thick, more preferably less than about 60 Angstroms thick, and more preferably from about 10 Angstroms to about 40 Angstroms thick.
- the structure of the carbon layer generally depends on the deposition approach.
- the carbon layer can be, for example, amorphous, graphitic, diamond-like-carbon, or a mixture thereof.
- the carbon can be doped to alter the properties of the carbon materials. Suitable dopants include, for example, hydrogen, nitrogen, and combinations thereof.
- the carbon can be deposited in the presence of hydrogen, generally diluted with inert gas, such as argon, to form hydrogen doped carbon.
- inert gas such as argon
- Addition of hydrogen in appropriate amounts maintains the hardness of the carbon layer while decreasing the elasticity, i.e., increasing the stiffness.
- the formation of a hydrogen doped carbon with increased wear resistance is described in U.S. Pat. No. 5,397,644, entitled “Magnetic Disk Having a Sputtered Hydrogen-Doped Carbon Protective Film,” incorporated herein by reference.
- a crosslinked fluoropolymer generally is bonded to the carbon layer.
- the crosslinking of the fluoropolymer is thought to result from the ejection of electrons by the substrate when subjected to crosslinking radiation.
- the polymer generally is crosslinked from the surface of the substrate outward.
- the thickness of the crosslinked polymer increases with increasing ultraviolet illumination time.
- the crosslinked portion of the substrate is bonded to the underlying carbon substrate. Due to the bonding of the crosslinked polymer with the carbon substrate, the crosslinked polymer will not spin-off of a rapidly rotating disc. Also, the crosslinked polymer is not removed by standard solvents that dissolve the uncrosslinked polymer. Standard solvents include halogenated alkanes, such as 1,1,2-trichloro trifluoroethane and perfluorooctane.
- the crosslinked polymer layer has a thickness less than about 30 angstroms, preferably less than about 25 angstroms and more preferably less than about 20 angstroms.
- the molecular weight of the polymer generally will be correlated with a minimum thickness of the crosslinked fluoropolymer layer.
- lubricant thickness is evaluated from the intensity of the C—F bond stretch absorption from an fourier transform infrared absorption measurement. The absorption intensity is calibrated using standards that are measured by Electron Spectroscopy for Chemical Analysis (ESCA), e.g. X-ray Photoelectron Spectroscopy.
- the thickness of the crosslinked polymer layer is evaluated following the removal of any uncrosslinked polymer, for example using a solvent or mechanical removal.
- the crosslinked polymer layer forms a more hydrophobic layer than the uncrosslinked lubricant. This can be quantified in the form of a water contact angle.
- the water contact angle is a measure of the hydrophobicity with an increased contact angle indicating that water beads up to greater extent because of increased hydrophobicity. With increased hydrophobicity, the layer provides more corrosion resistance with respect to the underlying materials.
- the crosslinked fluoropolymer layer has a water contact angle greater than about 100 degrees, preferably greater than about 105 degrees and more preferably greater than about 110 degrees. The water contact angle can be measured using available equipment, such as a Automated Goniometer from AST Products, Inc., Billerica, Mass.
- the crosslinked polymers form an effective sealer to supplement corrosion resistance provided by a protective carbon layer. Because of the sealing property of the crosslinked fluoropolymer layer against water-based corrosion, the crosslinked polymer layer can be used effectively with a thinner carbon coating to protect appropriately a magnetic layer against corrosion. In particular, the magnetic layer is protected against forms of corrosion induced by water, including oxidation and metal atom migration.
- the crosslinked fluoropolymer layer and thin carbon layer work synergistically to provide protection against both damage and wear from contact with the read/write head and corrosion of a magnetic substrate induced by water.
- the crosslinking can be performed such that the solid, crosslinked fluorinated polymer layer is located over only a portion of the substrate.
- Solid, crosslinked lubricant in the landing zone of the disc would be retained during a standard degreasing step, resulting in a stepped topcoat thickness at the edge of crosslinked polymer.
- different regions of the lubrication layer can be exposed to different amounts of crosslinking radiation, such that different thicknesses of solid, crosslinked fluoropolymer are formed at different locations along the substrate surface.
- a suitable carbon layer can be deposited by sputtering.
- Various forms of sputtering can be used, such as facing target sputtering, DC magnetion sputtering, RF magnetron sputtering, DC diode sputtering, RF diode sputtering, or physical vapor deposition sputtering.
- Other approaches can be used to deposit the carbon layer such as chemical vapor deposition, ion implantation, plasma spraying, plasma enhanced chemical vapor deposition, thermally assisted evaporation, and electron beam assisted vapor deposition.
- a thicker carbon layer is applied first to the surface using any desired process or processes, include conventional approaches, such as those described in the preceding paragraph.
- the relatively thick carbon coating is then etched to remove carbon to produce a desired carbon layer thickness.
- the etching preferably is performed using oxygen free radicals.
- the preferred approach to etch the carbon layer with oxygen free radicals involves the use of ozone in combination with ultraviolet light.
- the carbon film generally has a thickness less than about 100 angstroms, preferably less than about 80 angstroms, more preferably less than about 60 angstroms and even more preferably between about 10 angstroms and about 50 angstroms.
- the resulting carbon layer following etching is very smooth and very uniform.
- the production of a thin carbon layer by etching with ozone and ultraviolet light is described in commonly assigned and simultaneously filed U.S. patent application Ser. No., ___/___,____, entitled “Thin Carbon Films,” incorporated herein by reference.
- Formation of the crosslinked fluorocarbon layer involves two steps. In the first step a layer of uncrosslinked fluoropolymer is applies over a thin carbon coating. In the second step the fluoropolymer is crosslinked.
- the initial application of the uncrosslinked fluoropolymer can be applied by any of a variety of approaches, such as dipping, brushing, spin coating and the like.
- the initial thickness of the uncrosslinked lubricant generally range from about 20 angstroms to about 50 angstroms, and more preferably from about 30 angstroms to about 40 angstroms.
- the initial lubricant layer is then crosslinked by exposure to radiation.
- the lubricant coated carbon can be exposed to ultraviolet light or electron bombardment.
- ultraviolet radiation is particularly preferred.
- suitable wavelengths for crosslinking the polymer material depends on the chemical nature of the lubricant material and the carbon layer.
- ultraviolet light with a wavelength in the range of about 185 nm or less are suitable.
- a low pressure mercury lamp or a mercury arc lamp are suitable ultraviolet light sources with emissions at about 185 nm.
- the fluoropolymers can be crosslinked and bonded to the carbon substrate only over a portion of the carbon substrate.
- the thickness of the crosslinked fluoropolymer can be varied over different sections of the carbon substrate. This selective crosslinking to vary the location and/or thickness of the crosslinked polymer layer can be accomplished using a mask to block the crosslinking radiation, such as ultraviolet light, from striking portions of the substrate.
- photoresist can be selectively applied to block light during the ultraviolet irradiation process and subsequently removed in a chemical wash.
- Crosslinking and, in some embodiments, bonding of the fluoropolymer to the carbon layer only takes place at locations irradiated with the crosslinking radiation.
- a mask can be designed to block radiation from reaching the data zone of a magnetic storage disc such that the crosslinking radiation only strikes the landing zone.
- Use of the mask during the entire crosslinking process results in a bonded, crosslinked fluropolymer layer only over the landing zone of the disc.
- Use of the mask during only a portion of the crosslinking process results in a thicker crosslinked fluoropolymer layer over the landing zone in comparison with the data zone.
- Other patterns of crosslinking can be used as desired.
- the lubricant coatings were placed on NiP plated aluminum discs.
- the discs had a sputtered carbon coating.
- the carbon coated discs were coated with the uncrosslinked lubricant at a thickness of about 25 angstroms.
- the coated discs were closed within the unit prior to exposure to ultraviolet light.
- the unit was purged for two minute with dry nitrogen prior to the start of ultraviolet illumination, and the dry nitrogen purge was continued during the illumination.
- Selected disc surfaces were irradiated for either 15 seconds, 45 seconds or 90 seconds
- the resulting water contact angles measured with a goniometer for the lubricant coated discs are given in FIG. 6.
- the thicknesses were measured following the illumination process.
- the thicknesses of the crosslinked polymer were measured as a function of ultraviolet irradiation time.
- the uncrosslinked lubricant is removed by vapor degreasing with perfluorohexane (PF5060, 3M Corp., St. Paul, Minn.). The resulting thicknesses measured by fourier transform infrared spectroscopy are displayed in FIG. 7.
- Thickness of crosslinked polymer was also evaluated as a function of the thickness of the initial polymer layer using a lower molecular weight alcohol terminated perfluoropolyether, Ausimont® Z-dol, lubricant with an average molecular weight of about 1000 Daltons.
- the resulting thickness of the bonded, crosslinked lubricant are displayed in FIG. 9.
- Some uncrosslinked lubricant was lost during the crosslinking process. This loss of uncrosslinked lubricant evidently was due to thermal desorption.
- all three lubricant layers were essentially completely crosslinked following 300 seconds of ultraviolet irradiation.
- the first lubricant was the high molecular weight Ausimont® Z-dol with an average molecular weight of about 5500 Daltons.
- the second lubricant was a Fomblin® Ztetraol lubricant (Ausimont®). Ztetraol lubricant has a diol end group, CH 2 OCH 2 CHOHCH 2 OH.
- Carbon coatings were sputtered onto Hoya® alumino silicate amorphous glass substrates (Hoya Corp., Tokyo, Japan). Two different carbon coating thicknesses were tested, 15 Angstroms and 30 Angstroms. Crosslinking was performed by 15 seconds of UV exposure under the conditions described above.
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Metallurgy (AREA)
- Ceramic Engineering (AREA)
- Magnetic Record Carriers (AREA)
Abstract
Description
- This application claims priority under U.S. Provisional Application Serial No. 60/088,329 filed on Jun 4, 1998, entitled “CROSS LINKED FLUOROCARBON BARRIER COATING FOR THIN CARBON FILMS,” incorporated herein by reference, and under U.S. Provisional Application Serial No. 60/088,130 filed on Jun. 4, 1998, entitled “METHOD OF PRODUCING A ZONED SOLID LUBRICATED LAYER/BARRIER COATING,” incorporated herein by reference.
- The invention relates to films of crosslinked fluoropolymer that serve as lubrication and/or protection coatings. The invention more particularly relates to magnetic storage media having a crosslinked fluoropolymer lubricant layer.
- Advances in many technologies have created enhanced demands on materials used in the production of a variety of devices. Specifically, miniaturization has decreased tolerance levels while increasing performance requirements. Furthermore, coating technology has become extremely important since coatings can be used to alter the surface properties of the composite while maintaining desirable properties of the underlying substrate. In particular, thin coatings can serve to protect the underlying substrate from a variety of assaults.
- Data storage discs for the electronic storage of information are a device of particular interest. Disc drives for data storage can use one or more data storage discs with a magnetic medium for the storage of information. The magnetic medium generally is formed by a relatively thin magnetic layer on a non-magnetic substrate. Typically, the data is stored at specific locations along concentric data tracks. The disc drive assemblies for magnetic data storage include head/gimbal assemblies aligned with the disc surface. The head/gimbal assemblies support transducers, such as magnetoresistive elements, for reading data from and/or writing data to the data tracks near the disc surface.
- The read/write head generally includes an air bearing surface, which faces the disc surface. As the disc rotates, the disc drags air along the air bearing surface. As the air passes along the air bearing surface, the air pressure between the disc surface and the air bearing surface creates a hydrodynamic lifting force that causes the slider or head to deflect away from the disc surface. Prior to rotation of the disc, the slider rests on the disc surface. The hydrodynamic lift is affected by the speed of rotation of the disc, the design of the air bearing surface of the read/write head, and the preload force supplied to the head by the gimbal assembly.
- Discs can include separate landing zones and data storage zones on the disc surface. Information is stored in the magnetic media within the data storage zones. The landing zones are used to support the slider when the disc is not rotating. The landing zones also provide a takeoff and landing surface for the read/write head. The landing zone portion of the disc surface preferably is not used for data storage since repeated contact with the read/write head can destroy stored data in the magnetic medium near the disc surface.
- To obtain higher storage densities on the disc surface, fly heights between the read/write head and the disc surface are being reduced. Reducing the fly height improves the magnetic interaction between the head and the disc surface to allow correspondingly higher storage densities. Thus, it is important that the disc surface is sufficiently smooth for a particular fly height to reduce contacts between the read/write head and the disc surface. Contact between the read/write head and the disc surface can result in data loss and damage to the disc and/or the head.
- Furthermore, intermittent contact between the head and the disc surface causes wear of the disc surface. To protect the disc surface from wear and corrosion, overcoats can be placed on the disc surface over the magnetic medium. Preferred overcoats reduce wear and friction while maintaining proper hydrodynamic interaction between the head and the disc surface during rotation and during take-off and landing.
- Carbon coatings have been used to form protective layers on magnetic substrates. The coating, however, increases the spacing between the surface and the underlying substrate. Thus, for example in the production of magnetic discs, any performance improvement resulting from a reduction in fly height can be countered by the presence of protective coatings and the like that result in an increased distance of the magnetic medium and the disc surface.
- Furthermore, lubricant layers generally are used on magnetic disc surfaces to reduce wear and to decrease friction between the disc surface and the head. Perfluoropolyethers can be used to form the lubricant layer. A variety of approaches have been explored to secure the lubricant layer to the substrate such that the lubricant layer remains on the disc surface for a longer period of time.
- In a first aspect, the invention pertains to a magnetic storage medium comprising:
- a first protection means for protecting a magnetic substrate, the first protection means comprising a carbon material; and
- a second protection means for protecting a magnetic substrate, the second protection means comprising a crosslinked fluoropolymer.
- In another aspect, the invention pertains to a material comprising a magnetic substrate, a carbon layer covering at least a portion of the substrate and a crosslinked fluoropolymer layer covering at least a portion of a surface of the carbon layer, the crosslinked polymer layer having a thickness less than about 40 angstroms and the carbon layer having a thickness of less than about 100 angstroms.
- In a further aspect, the invention pertains to a material comprising a magnetic substrate, a carbon layer covering at least a portion of the substrate and a crosslinked fluoropolymer layer covering at least a portion of a surface of the carbon layer, wherein the crosslinked fluoropolymer layer has a thickness at one point on the carbon layer greater by at least about 5 angstroms than the thickness at another point on the carbon layer.
- Moreover, the invention pertains to a method of forming a lubrication layer of crosslinked fluoropolymer on a carbon substrate, the method comprising irradiating selected portions of the substrate with appropriate amounts of radiation to form a crosslinked fluoropolyer layer with different thicknesses of crosslinked polymer at different locations on the substrate.
- FIG. 1 is a schematic, perspective view of a substrate with a thin carbon coating.
- FIG. 2 is a sectional side view of the substrate with a thin carbon coating of FIG. 1.
- FIG. 3 is a perspective view of a magnetic storage disc with a thin carbon coating.
- FIG. 4 is a sectional side view of an embodiment of a magnetic storage disc.
- FIG. 5 is a schematic, top view of a disc drive system.
- FIG. 6 is a histogram plotting the water contact angle for two different perfluoropolyethers at three different ultraviolet irradiation times.
- FIG. 7 is a plot of total and crosslinked lubricant thickness as a function of ultraviolet irradiation time for two different perfluoropolyethers.
- FIG. 8 is a histogram plotting water contact angle as a function of ultraviolet irradiation time for a hydroxyl terminated perfluoropolyether.
- FIG. 9 is a plot of bonded polymer lubricant as a function of ultraviolet irradiation time for a hydroxyl terminated perfluoropolyether with three different initial thicknesses.
- FIG. 10 is a histogram plotting water contact angle for two different hydroxyl terminated perfluoro polyethers with and without ultraviolet irradiation and with two different initial polymer thicknesses.
- FIG. 11 is a histogram plotting lubricant thickness for two different hydroxyl terminated perfluoro polyethers with and without ultraviolet irradiation and with two different initial polymer thicknesses.
- Crosslinked fluoropolymer lubricant layers formed over a protective carbon layer provide protection against corrosion and wear in a synergistic fashion such that overall thickness of the protective coatings can be decreased. In particular, due to the corrosion inhibiting properties of a crosslinked fluoropolymer layer, a significantly thinner protective carbon layer can be used without diminishing the collective corrosion protection to unacceptable values. In preferred embodiments, a layer of crosslinked fluorinated polyether becomes bonded to the protective carbon layer during the crosslinking process. Radiation, preferably ultraviolet radiation, is used to crosslink the polymer adjacent to the carbon substrate. The thickness of the crosslinked portion of the lubricant layer can be adjusted by varying the length of time that the polymer is exposed to crosslinking radiation. The radiation can be directed during the crosslinking process to selected portions of the substrate to vary the crosslinked polymer thickness at different points along the carbon surface.
- Preferred structures include a lubricant layer over a carbon layer as protective layers that are applied to an underlying material. In preferred embodiments, the carbon layer is applied over a magnetic medium that is used for magnetic data storage. In particular, magnetic discs for electronic data storage have a magnetic layer used for data storage that can be coated with a protective carbon layer. In use, a read/write head or the like flies adjacent the disc surface when the disc is spinning. The head travels at a very small separation from the disc surface such that a lubricant layer improves performance at the head-disc interface.
- Generally, the lubricant layer is relatively thin, such that the distance between the head and the magnetic layers are not increased too significantly due to the presence of the lubrication layer. Also, because of the sealing property of a crosslinked fluoropolymer lubricant layer, a thinner carbon layer can be used than would be acceptable without the lubricant layer. Without the synergistic protection provided by the combination of the thin carbon layer and the crosslinked fluoropolymer, a carbon layer thinner than 100 angstroms does not provide sufficient protection against corrosion in the form of oxidation and cobalt migration. Thus, a crosslinked fluorocarbon layer can be used effectively with a carbon layer having a thickness less than 100 angstroms while providing adequate corrosion protection to a magnetic material under the carbon layer.
- The lubricant layer serves to decrease friction between a head and the disc, to provide some additional protection against impact and to seal the surface to inhibit corrosion of underlying magnetic layers by water coming into contact with the surface. Fluorine containing polyethers are particularly preferred in the lubricant layer due to their hydrophobic character. Preferred compounds for forming the lubrication layer include perfluoropolyethers and hydrofluoropolyethers.
- Suitable fluoropolyethers include unsubstituted perf luoropolyethers, such as Fomblin® Z-60 (average molecular weight (AMW)=about 60,000 atomic mass units (AMU) or Daltons), Fomblin® Z-25 (AMW=about 25,000 AMU) and Fomblin® Z-15 (AMW=about 15,000 AMU). The Fomblin® unsubstituted perfluoropolyethers made by Montedison (Ausimont) S.P.A., Milan, Italy have molecular formulas of CF3O(CF2CF2O)n(CF2O)mCF3, where n and m vary to yield particular products with average molecular weights of specified values. Suitable fluorinated polyethers include perfluoropolyethers with functional end groups. Suitable difunctional perfluoropolyethers include, for example, Fomblin® Z-DOL (hydroxyl end groups), Fomblin® AM2001 (piperonyl end groups), and Fomblin® Z-DISOC (isocyanate end groups). Fluorinated polymers with functional end groups may bind to a carbon substrate without the need for crosslinking radiation. Other suitable perfluoropolyethers are available under the tradenames Demnum® from Daikin Kogyo Co., Japan and Krytox® from DuPont, Wilmington, Del., having a basic molecular formula of F(CF2CF2CF2)nCF2CF3.
- Preferred unsubstituted fluorinated polyethers have average molecular weights less than about 100,000 AMU, preferably less than about 25,000 and more preferably from about 6000 AMU to about 15,000 AMU. Preferred fluorinated polyethers with functional end groups have average molecular weights less than about 10,000 AMU, preferably less than about 8,000 AMU and more preferably from about 1000 AMU to about 6,000 AMU.
- Upon exposure to crosslinking conditions, the fluorinated polyethers bind to the carbon layer to form a lubricant layer that does not migrate from the carbon layer. The inhibition of migration is particularly significant with magnetic disc applications where the spinning of the disc tends to remove fluid lubricants over time. Crosslinking within the fluorinated polyether polymers forms a solid layer of lubricant material extending from the carbon surface. Crosslinking increases the hydrophobicity of the lubrication layer, as evidenced by a corresponding increase in the water contact angle of water on the surface, as described further below.
- The crosslinking of the lubricant layer is performed with radiation, preferably ultraviolet light. Exposure to radiation induces the bonding of the lubricant compositions to the carbon layer. Further exposure to the crosslinking radiation results in a solid lubricant composition bonded adjacent to the carbon layer. The thickness of the resulting solid lubricant layer can be selected by the exposure time and radiation intensity. A liquid lubricant layer may remain over the solid lubricant, if sufficient radiation is not applied to crosslink the entire thickness of lubrication material. If desired, any remaining liquid lubricant can be removed with a solvent wash.
- In some preferred embodiments, the radiation is applied only to selected regions of the surface. The bonding to the carbon layer and the formation of the solid lubrication layer are only formed over the regions of the substrate exposed to the crosslinking radiation. Similarly, different regions of the substrate can be exposed to different amounts of radiation to vary the thickness of the corresponding solid, crosslinked polymer lubricant. The application of the radiation to selected portions of the substrate can be accomplished by blocking radiation from striking portions of the substrate or by the use of a focused radiation source, such as a ultraviolet laser, so that radiation is directed only to selected portions of the substrate.
- Referring to FIG. 1, an
article 100 includes asubstrate 102, acarbon layer 104 and alubricant layer 106. A cross section ofarticle 100 is shown in FIG. 2.Protective carbon layer 104 is located onsubstrate 102 below alubricant layer 106, which preferably includes a crosslinked fluoropolyer such as a crosslinked fluorinated polyether. -
Substrate 102 can be any material that will support the deposition of a carbon film. Generally,substrate 102 contributes functional properties to the device. The surface ofsubstrate 102 is protected bycarbon layer 104.Substrate material 102 can itself be a layer on a further support material. For example, if the object is a magnetic disc,substrate 102 generally includes a layer of magnetic material for data storage, as described further below. - In preferred embodiments,
lubricant layer 106 is located at the surface of a magnetic storage disc. Referring to FIG. 3, alubricant layer 140 is located at a surface of amagnetic storage disc 142.Lubricant layer 140 provides protection against abrasion and the like for a magnetic data storage material.Magnetic storage disc 142 can have any reasonable structure consistent withlubricant layer 140 providing a suitable interface formagnetic storage disc 142. - A cross section of a preferred embodiment of a
magnetic storage disc 150 is shown in FIG. 4. Asubstrate 152 forms the foundation or support structure forstorage disc 150. Thesubstrate 152 can be formed from aluminum, aluminum alloy, glass, polymer or other stable non-magnetic material or materials. Aluminum substrates can be plated with Ni—P or the like prior to application of additional layers.Substrate 152 can include multiple layers, if desired. Amagnetic layer 154 is located onsubstrate 152.Magnetic layer 154 is used for data storage ondisc 150.Magnetic layer 154 can be formed from a variety of magnetic materials, such as cobalt-based alloys or compounds including, for example, Co—Ni, Co—Cr, Co—Ni—Cr, Co—Pt, Co—Ni—Pt, Co—Cr—Ta, Co—Cr—Pt, Co—Cr—Ni—B, Co—P, Co—Ni—P, other similar materials and mixtures thereof. - A
protective carbon layer 156 is located on themagnetic layer 154,opposite substrate 152. An,optional spacer layer 158 and alubricant layer 160 are located adjacentprotective carbon layer 154.Optional spacer layer 158 preferably is formed from a non-magnetic material and is located betweenprotective carbon layer 156 andmagnetic layer 154. Suitable materials forspacer layer 158 include, for example, silicon, germanium, tin, titanium, molybdenum and tungsten.Spacer layer 158 preferably has a thickness from about 1 nm to about 7 nm.Spacer layer 158 can be formed by sputtering or other similar vapor phase deposition approaches. The use of a spacer layer is described further in U.S. Pat. No. 5,871,841, entitled “Magnetic Disk Medium,” incorporated herein by reference. -
Lubricant layer 160 is used to form a more preferred hydrodynamic interface between a read/write head andmagnetic storage disc 150. Following crosslinking,lubricant layer 160 generally is chemically bonded tocarbon layer 154.Lubricant layer 160 includes acrosslinked portion 162. Optionally,lubricant layer 160 can include anuncrosslinked portion 164. Uncrosslinked lubricant can be removed as described below. Whilecrosslinked portion 162 anduncrosslinked portion 164 are depicted as distinct layers marked with a dashed line in FIG. 4, the layers may not be clearly physically separated due to interpenetration of the layers. - A magnetic disc with a combination of a thin protective carbon layer and a crosslinked fluorinated polymer layer, as described herein, can be used in a disc drive system. FIG. 5 depicts an embodiment of a
disc drive system 200 includingdrive unit 202, actuator assembly 204 andcontroller 206.Drive unit 202 includesdisc 208 andspindle 210 connected to a spindle motor. In the embodiment shown, actuator assembly 204 includesactuator 212,support arm 214,load beam 216 and gimble/head assembly 218.Actuator 212 controls the position of gimble/head assembly 218 overdisc 208 by rotating or laterally movingsupport arm 214.Load beam 216 is located at the end ofsupport arm 214 and gimble/head assembly 218 is located at the end ofload beam 216.Controller 206 instructsactuator 212 regarding the position ofsupport arm 214 overdisc 208 and driveunit 202 regarding the control of the spindle motor. - Together the carbon layer and lubricant layer form a protective overcoat for an underlying substrate, such as a magnetic material. In preferred embodiments, the carbon layer is less than about 100 Angstroms thick, preferably less than about 80 Angstroms thick, more preferably less than about 60 Angstroms thick, and more preferably from about 10 Angstroms to about 40 Angstroms thick. The structure of the carbon layer generally depends on the deposition approach. In particular, the carbon layer can be, for example, amorphous, graphitic, diamond-like-carbon, or a mixture thereof. Furthermore, the carbon can be doped to alter the properties of the carbon materials. Suitable dopants include, for example, hydrogen, nitrogen, and combinations thereof.
- In particular, the carbon can be deposited in the presence of hydrogen, generally diluted with inert gas, such as argon, to form hydrogen doped carbon. Addition of hydrogen in appropriate amounts maintains the hardness of the carbon layer while decreasing the elasticity, i.e., increasing the stiffness. The formation of a hydrogen doped carbon with increased wear resistance is described in U.S. Pat. No. 5,397,644, entitled “Magnetic Disk Having a Sputtered Hydrogen-Doped Carbon Protective Film,” incorporated herein by reference.
- As noted above, a crosslinked fluoropolymer generally is bonded to the carbon layer. The crosslinking of the fluoropolymer is thought to result from the ejection of electrons by the substrate when subjected to crosslinking radiation. Thus, the polymer generally is crosslinked from the surface of the substrate outward. As demonstrated in the examples below, the thickness of the crosslinked polymer increases with increasing ultraviolet illumination time.
- Following crosslinking, the crosslinked portion of the substrate is bonded to the underlying carbon substrate. Due to the bonding of the crosslinked polymer with the carbon substrate, the crosslinked polymer will not spin-off of a rapidly rotating disc. Also, the crosslinked polymer is not removed by standard solvents that dissolve the uncrosslinked polymer. Standard solvents include halogenated alkanes, such as 1,1,2-trichloro trifluoroethane and perfluorooctane.
- In preferred embodiments, the crosslinked polymer layer has a thickness less than about 30 angstroms, preferably less than about 25 angstroms and more preferably less than about 20 angstroms. The molecular weight of the polymer generally will be correlated with a minimum thickness of the crosslinked fluoropolymer layer. In one approach, lubricant thickness is evaluated from the intensity of the C—F bond stretch absorption from an fourier transform infrared absorption measurement. The absorption intensity is calibrated using standards that are measured by Electron Spectroscopy for Chemical Analysis (ESCA), e.g. X-ray Photoelectron Spectroscopy. The thickness of the crosslinked polymer layer is evaluated following the removal of any uncrosslinked polymer, for example using a solvent or mechanical removal.
- The crosslinked polymer layer forms a more hydrophobic layer than the uncrosslinked lubricant. This can be quantified in the form of a water contact angle. The water contact angle is a measure of the hydrophobicity with an increased contact angle indicating that water beads up to greater extent because of increased hydrophobicity. With increased hydrophobicity, the layer provides more corrosion resistance with respect to the underlying materials. In preferred embodiments, the crosslinked fluoropolymer layer has a water contact angle greater than about 100 degrees, preferably greater than about 105 degrees and more preferably greater than about 110 degrees. The water contact angle can be measured using available equipment, such as a Automated Goniometer from AST Products, Inc., Billerica, Mass.
- Thus, the crosslinked polymers form an effective sealer to supplement corrosion resistance provided by a protective carbon layer. Because of the sealing property of the crosslinked fluoropolymer layer against water-based corrosion, the crosslinked polymer layer can be used effectively with a thinner carbon coating to protect appropriately a magnetic layer against corrosion. In particular, the magnetic layer is protected against forms of corrosion induced by water, including oxidation and metal atom migration. The crosslinked fluoropolymer layer and thin carbon layer work synergistically to provide protection against both damage and wear from contact with the read/write head and corrosion of a magnetic substrate induced by water.
- As noted above, the crosslinking can be performed such that the solid, crosslinked fluorinated polymer layer is located over only a portion of the substrate. For example, it may be desirable to form a solid, crosslinked lubricant layer in the data zone of the media, to minimize the probability of fly stiction events while improving corrosion resistance. Alternatively, it may be advantageous to form selectively crosslinked fluorinated polymers in the landing zone of the media, to improve the friction and wear characteristics of the media. Solid, crosslinked lubricant in the landing zone of the disc would be retained during a standard degreasing step, resulting in a stepped topcoat thickness at the edge of crosslinked polymer. Similarly, different regions of the lubrication layer can be exposed to different amounts of crosslinking radiation, such that different thicknesses of solid, crosslinked fluoropolymer are formed at different locations along the substrate surface.
- A suitable carbon layer can be deposited by sputtering. Various forms of sputtering can be used, such as facing target sputtering, DC magnetion sputtering, RF magnetron sputtering, DC diode sputtering, RF diode sputtering, or physical vapor deposition sputtering. Other approaches can be used to deposit the carbon layer such as chemical vapor deposition, ion implantation, plasma spraying, plasma enhanced chemical vapor deposition, thermally assisted evaporation, and electron beam assisted vapor deposition.
- In a preferred approach to the production of a thin, smooth carbon layer, a thicker carbon layer is applied first to the surface using any desired process or processes, include conventional approaches, such as those described in the preceding paragraph. The relatively thick carbon coating is then etched to remove carbon to produce a desired carbon layer thickness. The etching preferably is performed using oxygen free radicals. The preferred approach to etch the carbon layer with oxygen free radicals involves the use of ozone in combination with ultraviolet light.
- Following etching, the carbon film generally has a thickness less than about 100 angstroms, preferably less than about 80 angstroms, more preferably less than about 60 angstroms and even more preferably between about 10 angstroms and about 50 angstroms. The resulting carbon layer following etching is very smooth and very uniform. The production of a thin carbon layer by etching with ozone and ultraviolet light is described in commonly assigned and simultaneously filed U.S. patent application Ser. No., ___/___,___, entitled “Thin Carbon Films,” incorporated herein by reference.
- Formation of the crosslinked fluorocarbon layer involves two steps. In the first step a layer of uncrosslinked fluoropolymer is applies over a thin carbon coating. In the second step the fluoropolymer is crosslinked. The initial application of the uncrosslinked fluoropolymer can be applied by any of a variety of approaches, such as dipping, brushing, spin coating and the like. The initial thickness of the uncrosslinked lubricant generally range from about 20 angstroms to about 50 angstroms, and more preferably from about 30 angstroms to about 40 angstroms.
- The initial lubricant layer is then crosslinked by exposure to radiation. In particular, the lubricant coated carbon can be exposed to ultraviolet light or electron bombardment. The use of ultraviolet radiation is particularly preferred. Generally, suitable wavelengths for crosslinking the polymer material depends on the chemical nature of the lubricant material and the carbon layer. To crosslink perfluoropolyethers on a carbon layer, ultraviolet light with a wavelength in the range of about 185 nm or less are suitable. A low pressure mercury lamp or a mercury arc lamp are suitable ultraviolet light sources with emissions at about 185 nm.
- As noted above, the fluoropolymers can be crosslinked and bonded to the carbon substrate only over a portion of the carbon substrate. Similarly, the thickness of the crosslinked fluoropolymer can be varied over different sections of the carbon substrate. This selective crosslinking to vary the location and/or thickness of the crosslinked polymer layer can be accomplished using a mask to block the crosslinking radiation, such as ultraviolet light, from striking portions of the substrate. Similarly, photoresist can be selectively applied to block light during the ultraviolet irradiation process and subsequently removed in a chemical wash.
- Crosslinking and, in some embodiments, bonding of the fluoropolymer to the carbon layer only takes place at locations irradiated with the crosslinking radiation. For example, a mask can be designed to block radiation from reaching the data zone of a magnetic storage disc such that the crosslinking radiation only strikes the landing zone. Use of the mask during the entire crosslinking process results in a bonded, crosslinked fluropolymer layer only over the landing zone of the disc. Use of the mask during only a portion of the crosslinking process results in a thicker crosslinked fluoropolymer layer over the landing zone in comparison with the data zone. Other patterns of crosslinking can be used as desired.
- A first set of experiments were preformed with perfluoropolyethers without functional end groups. In these experiments, the water contact angle was measured for various crosslinked polymers. Two different perfluoropolyethanes were used. Ausimont® Z-15 had an average molecular weight of about 15,000, and Ausimont® Z-60 had a molecular weight of about 60,000. The Z-15 polymers had the lightest fractions removed by distilling the composition at 295° C. The crosslinking was performed with a Samco desktop UV/ozone etcher Model UV-1 (Samco Keyoto International, Inc., Japan), having a mercury discharge UV lamp with emissions primarily at 254 nm (85%) and 184 nm (15%). Based on the manufacturer's specifications and the configuration of the apparatus, the intensity at the disc surfaces was assumed to be 54±1 mW.
- The lubricant coatings were placed on NiP plated aluminum discs. The discs had a sputtered carbon coating. The carbon coated discs were coated with the uncrosslinked lubricant at a thickness of about 25 angstroms. Then, the coated discs were closed within the unit prior to exposure to ultraviolet light. The unit was purged for two minute with dry nitrogen prior to the start of ultraviolet illumination, and the dry nitrogen purge was continued during the illumination. Selected disc surfaces were irradiated for either 15 seconds, 45 seconds or 90 seconds The resulting water contact angles measured with a goniometer for the lubricant coated discs are given in FIG. 6. The thicknesses were measured following the illumination process. Also, the thicknesses of the crosslinked polymer were measured as a function of ultraviolet irradiation time. To measure the thicknesses of the crosslinked lubricant, the uncrosslinked lubricant is removed by vapor degreasing with perfluorohexane (PF5060, 3M Corp., St. Paul, Minn.). The resulting thicknesses measured by fourier transform infrared spectroscopy are displayed in FIG. 7.
- Other experiments were performed using alcohol terminated perfluoropolyethers. In these experiments, the lubricant coatings were placed on NiP plated aluminum discs with a sputtered carbon coating. The uncrosslinked lubricant was Ausimont® Z-dol with an average molecular weight of about 5500 Daltons. The measured water contact angle starting with a 35 Angstrom coating of uncrosslinked lubricant are displayed in FIG. 8. The water contact angle of the disc without any crosslinking was 97.1.
- Thickness of crosslinked polymer was also evaluated as a function of the thickness of the initial polymer layer using a lower molecular weight alcohol terminated perfluoropolyether, Ausimont® Z-dol, lubricant with an average molecular weight of about 1000 Daltons. The resulting thickness of the bonded, crosslinked lubricant are displayed in FIG. 9. Some uncrosslinked lubricant was lost during the crosslinking process. This loss of uncrosslinked lubricant evidently was due to thermal desorption. For the three initial lubricant thicknesses tested, all three lubricant layers were essentially completely crosslinked following 300 seconds of ultraviolet irradiation.
- Additional experiments were performed comparing two different hydroxyl terminated perfluoropolyether polymer lubricants. The first lubricant was the high molecular weight Ausimont® Z-dol with an average molecular weight of about 5500 Daltons. The second lubricant was a Fomblin® Ztetraol lubricant (Ausimont®). Ztetraol lubricant has a diol end group, CH2OCH2CHOHCH2OH. Carbon coatings were sputtered onto Hoya® alumino silicate amorphous glass substrates (Hoya Corp., Tokyo, Japan). Two different carbon coating thicknesses were tested, 15 Angstroms and 30 Angstroms. Crosslinking was performed by 15 seconds of UV exposure under the conditions described above.
- The resulting water contact angles are depicted in FIG. 10. The Ztetraol polymers exhibited greater increases in water contact angle as a result of crosslinking. The corresponding lubricant thicknesses, before and after vapor degrease, are depicted in FIG. 11.
- Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
Claims (20)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/323,510 US6589641B1 (en) | 1998-06-04 | 1999-06-01 | Thin films of crosslinked fluoropolymer on a carbon substrate |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US8832998P | 1998-06-04 | 1998-06-04 | |
US8813098P | 1998-06-04 | 1998-06-04 | |
US09/323,510 US6589641B1 (en) | 1998-06-04 | 1999-06-01 | Thin films of crosslinked fluoropolymer on a carbon substrate |
Publications (2)
Publication Number | Publication Date |
---|---|
US6589641B1 US6589641B1 (en) | 2003-07-08 |
US20030129372A1 true US20030129372A1 (en) | 2003-07-10 |
Family
ID=27375899
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/323,510 Expired - Fee Related US6589641B1 (en) | 1998-06-04 | 1999-06-01 | Thin films of crosslinked fluoropolymer on a carbon substrate |
Country Status (1)
Country | Link |
---|---|
US (1) | US6589641B1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080081220A1 (en) * | 1999-10-22 | 2008-04-03 | Fujitsu Limited | Magnetic disk drive having a surface coating on a magnetic disk |
US20120295134A1 (en) * | 2010-02-10 | 2012-11-22 | Moresco Corporation | Perfluoropolyether compound, manufacturing method therefor, lubricant containing said compound, and magnetic disc |
Families Citing this family (24)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6243938B1 (en) * | 1998-03-17 | 2001-06-12 | Becton, Dickinson And Company | Low silicone plastic prefillable syringe |
US6849304B1 (en) * | 2001-03-16 | 2005-02-01 | Seagate Technology Llc | Method of forming lubricant films |
GB0114265D0 (en) | 2001-06-12 | 2001-08-01 | Ciba Sc Holding Ag | Polymeric material containing a latent acid |
GB0206930D0 (en) * | 2002-03-23 | 2002-05-08 | Univ Durham | Method and apparatus for the formation of hydrophobic surfaces |
US7018681B2 (en) * | 2002-03-29 | 2006-03-28 | Seagate Technology Llc | Reducing UV process time on storage media |
JP4247535B2 (en) * | 2003-11-11 | 2009-04-02 | Hoya株式会社 | Magnetic disk for load / unload system, method for manufacturing magnetic disk for load / unload system, and method for evaluating magnetic disk for load / unload system |
WO2005054353A1 (en) * | 2003-11-21 | 2005-06-16 | Ciba Specialty Chemicals Holding Inc. | Weatherfast pigmented polystyrene |
US7244521B2 (en) * | 2003-12-19 | 2007-07-17 | Seagate Technology Llc | System and method for improving corrosion resistance of magnetic media |
JP4078317B2 (en) * | 2004-02-06 | 2008-04-23 | Hoya株式会社 | Solid surface evaluation method, magnetic disk evaluation method, magnetic disk and manufacturing method thereof |
JP2006012215A (en) * | 2004-06-22 | 2006-01-12 | Toshiba Corp | Magnetic recording medium and magnetic recording and reproducing device using the same |
US20060105203A1 (en) * | 2004-11-15 | 2006-05-18 | Seagate Technology Llc | Head disc interface design |
US7508632B2 (en) * | 2005-07-25 | 2009-03-24 | Seagate Technology Llc | Head-disc interface (HDI) with solid lubricants |
US20070166481A1 (en) * | 2006-01-13 | 2007-07-19 | Seagate Technology Llc | In-situ UV curing of media lubricants |
US8286561B2 (en) | 2008-06-27 | 2012-10-16 | Ssw Holding Company, Inc. | Spill containing refrigerator shelf assembly |
MX345941B (en) * | 2008-06-27 | 2017-02-27 | Ssw Holding Co Inc | Method for spill containment and shelves or the like therefore. |
US7914845B2 (en) * | 2008-07-25 | 2011-03-29 | Seagate Technology Llc | Data zone lube removal |
WO2010042191A1 (en) | 2008-10-07 | 2010-04-15 | Ross Technology Corporation | Highly durable superhydrophobic, oleophobic and anti-icing coatings and methods and compositions for their preparation |
MX343584B (en) | 2009-11-04 | 2016-11-10 | Ssw Holding Co Inc | Cooking appliance surfaces having spill containment pattern and methods of making the same. |
EP2547832A4 (en) | 2010-03-15 | 2016-03-16 | Ross Technology Corp | Plunger and methods of producing hydrophobic surfaces |
JP2014512417A (en) | 2011-02-21 | 2014-05-22 | ロス テクノロジー コーポレーション. | Superhydrophobic and oleophobic coatings containing low VOC binder systems |
WO2013090939A1 (en) | 2011-12-15 | 2013-06-20 | Ross Technology Corporation | Composition and coating for superhydrophobic performance |
US20130161181A1 (en) * | 2011-12-21 | 2013-06-27 | Hitachi Global Storage Technologies Netherlands B.V. | Method for manufacturing a magnetic recording disk with improved yield |
AU2013281220B2 (en) | 2012-06-25 | 2017-03-16 | Ross Technology Corporation | Elastomeric coatings having hydrophobic and/or oleophobic properties |
US9312141B2 (en) | 2013-11-21 | 2016-04-12 | HGST Netherlands B.V. | Vapor phase chemical mechanical polishing of magnetic recording disks |
Family Cites Families (60)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3025279A (en) | 1955-06-29 | 1962-03-13 | Pennsalt Chemicals Corp | Copolymers of trifluoroethyl vinyl ether and fluoroalkyl acrylates, and process for preparing same |
US3104983A (en) | 1959-08-26 | 1963-09-24 | Ibm | Method of curing magnetic tape binder comprising butadiene-acrylonitrile and phenolicresin with subatomic radiation |
US3810874A (en) | 1969-03-10 | 1974-05-14 | Minnesota Mining & Mfg | Polymers prepared from poly(perfluoro-alkylene oxide) compounds |
US3814741A (en) | 1970-01-24 | 1974-06-04 | Montedison Spa | Acrylic and methacrylic monomers,polymers and copolymers thereof |
US4132681A (en) | 1976-10-29 | 1979-01-02 | United States Of America As Represented By The Secretary Of The Navy | Fluorinated polyether network polymers |
JPS57134558A (en) | 1981-02-16 | 1982-08-19 | Fuji Photo Film Co Ltd | Production of organic vapor deposited thin film |
JPS57143728A (en) | 1981-02-27 | 1982-09-06 | Fuji Photo Film Co Ltd | Magnetic recording medium |
JPS57150136A (en) | 1981-03-09 | 1982-09-16 | Fuji Photo Film Co Ltd | Magnetic recording medium and its manufacture |
US4404247A (en) | 1982-07-02 | 1983-09-13 | Minnesota Mining And Manufacturing Company | Protective covering for magnetic recording medium |
DE3370710D1 (en) | 1982-11-19 | 1987-05-07 | Matsushita Electric Ind Co Ltd | Magnetic recording medium |
US4446193A (en) | 1983-04-29 | 1984-05-01 | International Business Machines Corporation | Process for chemically bonding lubricant to an information carrier and products thereof |
US4671999A (en) | 1983-09-19 | 1987-06-09 | Minnesota Mining And Manufacturing Company | Magnetic recording media having perfluoropolyether coating |
US4569962A (en) | 1983-09-19 | 1986-02-11 | Minnesota Mining And Manufacturing Company | Perfluoropolyether compositions which are soluble in non-fluorinated solvents |
US4705699A (en) | 1983-09-19 | 1987-11-10 | Minnesota Mining And Manufacturing Company | Method of coating magnetic recording media with perfluoropolyether compositions which are soluble in non-fluorinated solvents |
US4526833A (en) | 1983-10-03 | 1985-07-02 | Minnesota Mining And Manufacturing Company | Magnetic recording medium having a perfluoropolyether polymer protective coating |
JPS60111340A (en) | 1983-11-21 | 1985-06-17 | Fuji Photo Film Co Ltd | Flexible magnetic disc |
DE3502852C2 (en) | 1984-02-01 | 1999-06-24 | Tdk Corp | Magnetic recording material |
JPS6139921A (en) | 1984-07-31 | 1986-02-26 | Tdk Corp | Magnetic recording medium and magnetic recording method |
JPS6142723A (en) | 1984-08-02 | 1986-03-01 | Tdk Corp | Magnetic recording medium and magnetic recording method |
JPS61115238A (en) | 1984-11-09 | 1986-06-02 | Fuji Photo Film Co Ltd | Flexible magnetic disk and its manufacture |
JPS61122925A (en) | 1984-11-19 | 1986-06-10 | Matsushita Electric Ind Co Ltd | Magnetic recording medium and its production |
IT1185520B (en) | 1985-02-22 | 1987-11-12 | Montefluos Spa | POLYACRYLATES AND FLUORINATED POLYACRYLAMIDS WITH A CONTROLLED RETICULATION DEGREE AND THEIR PREPARATION PROCEDURE |
JPS61240430A (en) | 1985-04-18 | 1986-10-25 | Tdk Corp | Magnetic recording medium |
US4642246A (en) | 1985-11-12 | 1987-02-10 | Magnetic Peripherals, Inc. | Process for chemically bonding a lubricant to a magnetic disk |
US4686146A (en) | 1986-02-18 | 1987-08-11 | Memorex Corporation | Radiation-cured recording composition with bi-part lube |
US4880687A (en) | 1986-05-09 | 1989-11-14 | Tdk Corporation | Magnetic recording medium |
JPH01501185A (en) | 1986-08-28 | 1989-04-20 | ユニシス・コーポレーシヨン | Surface lubricant for recording surfaces |
US4849291A (en) | 1987-12-02 | 1989-07-18 | Eastman Kodak Company | Magnetic recording element |
JPH01195720A (en) | 1988-01-04 | 1989-08-07 | Nec Corp | Semiconductor integrated circuit |
US5030478A (en) | 1989-03-03 | 1991-07-09 | International Business Machines Corporation | Process for bonding lubricants to thin film recording media |
GB8916739D0 (en) | 1989-07-21 | 1989-09-06 | Minnesota Mining & Mfg | Protective layer for magnetic recording media |
JP2687245B2 (en) | 1989-09-29 | 1997-12-08 | 富士写真フイルム株式会社 | Manufacturing method of magnetic recording medium |
US5049410A (en) | 1989-11-01 | 1991-09-17 | International Business Machines Corporation | Lubricant film for a thin-film disk |
US4960609A (en) | 1989-11-13 | 1990-10-02 | International Business Machines Corporation | Process for bonding lubricant to a thin film magnetic recording disk |
US5055359A (en) | 1989-12-14 | 1991-10-08 | Nippon Sheet Glass Co., Ltd. | Magnetic recording medium with an intermediate protective layer of silicon dioxide and a perfluoroalkylpolyether lubricant layer |
US5266724A (en) | 1990-09-04 | 1993-11-30 | Matsushita Electric Industrial Co., Ltd. | Fluorine-containing compounds |
US5188747A (en) | 1990-09-04 | 1993-02-23 | Matsushita Electric Industrial Co., Ltd. | Fluorine-containing lubricant compounds |
JP2781656B2 (en) | 1990-11-21 | 1998-07-30 | 株式会社日立製作所 | recoding media |
JP2566700B2 (en) | 1991-04-08 | 1996-12-25 | インターナショナル・ビジネス・マシーンズ・コーポレイション | Method of bonding a lubricant on a thin film storage medium |
DE69219521T2 (en) | 1991-07-15 | 1997-08-14 | Matsushita Electric Ind Co Ltd | Magnetic recording medium, sliding body and method for its production |
US5637411A (en) | 1991-07-29 | 1997-06-10 | Hitachi Maxell, Ltd. | Magneto-optical recording medium and process for producing the same |
US5279877A (en) | 1991-09-06 | 1994-01-18 | Tdk Corporation | Magneto optical disc |
US5618617A (en) | 1991-12-02 | 1997-04-08 | Matsushita Electric Industrial Co., Ltd. | Magneto-optic disk |
US5331487A (en) | 1992-01-16 | 1994-07-19 | International Business Machines Corporation | Direct access storage device with vapor phase lubricant system and a magnetic disk having a protective layer and immobile physically bonded lubricant layer |
JP2915251B2 (en) * | 1993-06-28 | 1999-07-05 | 株式会社日立製作所 | Magnetic recording medium and method of manufacturing the same |
US5534322A (en) | 1993-06-29 | 1996-07-09 | Kao Corporation | Recording medium |
JP3378618B2 (en) | 1993-08-06 | 2003-02-17 | 株式会社日立製作所 | Magnetic recording media |
JP2746073B2 (en) | 1993-08-25 | 1998-04-28 | 日本電気株式会社 | Manufacturing method of magnetic memory |
JPH07141648A (en) | 1993-09-27 | 1995-06-02 | Sumitomo Metal Mining Co Ltd | Producing device of magnetic disk and production of magnetic disk |
JP3449637B2 (en) | 1993-12-28 | 2003-09-22 | Hoya株式会社 | Magnetic recording medium, method of manufacturing the same, and method of evaluating magnetic recording medium |
US5750747A (en) | 1994-12-14 | 1998-05-12 | Hitachi Maxell, Ltd. | Organic triblock compound solid lubricant comprising the same and magnetic recording medium |
US5912061A (en) | 1995-08-03 | 1999-06-15 | Matsushita Electric Industrial Co., Ltd. | UV-ray setting resin and a method for manufacturing a magneto-optical disk by the use of the UV-ray setting resin |
US5661618A (en) | 1995-12-11 | 1997-08-26 | International Business Machines Corporation | Magnetic recording device having a improved slider |
US5650900A (en) | 1996-02-05 | 1997-07-22 | Seagate Technology, Inc. | Magnetic disc with zoned lubricant thickness |
JP3253851B2 (en) * | 1996-04-18 | 2002-02-04 | 株式会社日立製作所 | Super water repellent paint and super water repellent coating using the same |
US5874169A (en) | 1997-03-17 | 1999-02-23 | Seagate Technology, Inc. | Polymeric perfluoro polyether phosphate lubricant topcoat |
JPH1186275A (en) * | 1997-09-12 | 1999-03-30 | Sony Corp | Magnetic recording medium |
JP4099860B2 (en) | 1997-10-09 | 2008-06-11 | 富士電機デバイステクノロジー株式会社 | Liquid lubricant, magnetic recording medium using the same, and manufacturing method thereof |
US6096385A (en) | 1998-02-19 | 2000-08-01 | Trace Storage Tech. Corp. | Method for making magnetic disks with uneven distribution of bonded/unbonded lubricating molecules |
US6099762A (en) | 1998-12-21 | 2000-08-08 | Lewis; Paul E. | Method for improving lubricating surfaces on disks |
-
1999
- 1999-06-01 US US09/323,510 patent/US6589641B1/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080081220A1 (en) * | 1999-10-22 | 2008-04-03 | Fujitsu Limited | Magnetic disk drive having a surface coating on a magnetic disk |
US20120295134A1 (en) * | 2010-02-10 | 2012-11-22 | Moresco Corporation | Perfluoropolyether compound, manufacturing method therefor, lubricant containing said compound, and magnetic disc |
Also Published As
Publication number | Publication date |
---|---|
US6589641B1 (en) | 2003-07-08 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6589641B1 (en) | Thin films of crosslinked fluoropolymer on a carbon substrate | |
US7833641B2 (en) | Magnetic disk | |
US5661618A (en) | Magnetic recording device having a improved slider | |
US7354666B2 (en) | Photo process to improve tribological performance of thin lubricant film | |
US5650900A (en) | Magnetic disc with zoned lubricant thickness | |
US6680079B1 (en) | Planarization and corrosion protection of patterned magnetic media | |
JP2007087463A (en) | Magnetic recording medium, its manufacturing method and magnetic recording and reproducing apparatus | |
US10783916B1 (en) | Passivated nitrogenated diamond-like carbon layer and method for passivating it | |
US20050037932A1 (en) | Ultra-thin lubricant film for advanced tribological performance of magnetic storage media | |
US5543203A (en) | Magnetic recording medium having a protective layer which includes high and low surface energy regions and a lubricant | |
US6416839B1 (en) | Magnetic recording medium with laser-formed differential zone lubrication | |
US7508632B2 (en) | Head-disc interface (HDI) with solid lubricants | |
US7060377B2 (en) | Lubricant film containing additives for advanced tribological performance of magnetic storage medium | |
US20080024923A1 (en) | Lubricant film forming method, slide body with lubricant film, magnetic recording medium, magnetic head slider, and hard disk drive | |
US6753060B1 (en) | Method for improving performance of thin film recording media and media obtained thereby | |
US6686019B1 (en) | In-situ stabilization of composite lubricant/additive films on thin film media | |
US6673429B1 (en) | Magnetic recording media with a multiple-layer lubricant | |
US6477011B1 (en) | Magnetic recording device having an improved slider | |
JPH117657A (en) | Optical recording medium, optical head and optical recording device | |
US20130163119A1 (en) | Head-Media Interface in a Hard Disk Drive | |
US6656333B2 (en) | Process for making patterned magnetic recording media employing a nonfunctional lubricant | |
US6468596B1 (en) | Laser-assisted in-situ fractionated lubricant and a new process for surface of magnetic recording media | |
US20090263592A1 (en) | Plasma-enhanced chemical vapor deposition of advanced lubricant for thin film storage medium | |
US6804878B1 (en) | Method of improving the reliability of magnetic head sensors by ion milling smoothing | |
US6916510B1 (en) | Method for improving efficiency of UV curing of lubricant thin films and improved data/information storage media obtained thereby |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: SEAGATE TECHNOLOGY, INC., CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:STIRNIMAN, MICHAEL J.;FALCONE, SAMUEL J.;WANG, LI-PING;AND OTHERS;REEL/FRAME:010087/0610 Effective date: 19990601 |
|
AS | Assignment |
Owner name: SEAGATE TECHNOLOGY LLC, CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SEAGATE TECHNOLOGY, INC.;REEL/FRAME:010985/0434 Effective date: 20000628 |
|
AS | Assignment |
Owner name: JPMORGAN CHASE BANK, AS COLLATERAL AGENT, NEW YORK Free format text: SECURITY AGREEMENT;ASSIGNOR:SEAGATE TECHNOLOGY LLC;REEL/FRAME:013177/0001 Effective date: 20020513 Owner name: JPMORGAN CHASE BANK, AS COLLATERAL AGENT,NEW YORK Free format text: SECURITY AGREEMENT;ASSIGNOR:SEAGATE TECHNOLOGY LLC;REEL/FRAME:013177/0001 Effective date: 20020513 |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
AS | Assignment |
Owner name: SEAGATE TECHNOLOGY LLC, CALIFORNIA Free format text: RELEASE OF SECURITY INTERESTS IN PATENT RIGHTS;ASSIGNOR:JPMORGAN CHASE BANK, N.A. (FORMERLY KNOWN AS THE CHASE MANHATTAN BANK AND JPMORGAN CHASE BANK), AS ADMINISTRATIVE AGENT;REEL/FRAME:016958/0340 Effective date: 20051130 |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
SULP | Surcharge for late payment | ||
AS | Assignment |
Owner name: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT Free format text: SECURITY AGREEMENT;ASSIGNORS:MAXTOR CORPORATION;SEAGATE TECHNOLOGY LLC;SEAGATE TECHNOLOGY INTERNATIONAL;REEL/FRAME:022757/0017 Effective date: 20090507 Owner name: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS COLLATE Free format text: SECURITY AGREEMENT;ASSIGNORS:MAXTOR CORPORATION;SEAGATE TECHNOLOGY LLC;SEAGATE TECHNOLOGY INTERNATIONAL;REEL/FRAME:022757/0017 Effective date: 20090507 |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
AS | Assignment |
Owner name: SEAGATE TECHNOLOGY HDD HOLDINGS, CALIFORNIA Free format text: RELEASE;ASSIGNOR:JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT;REEL/FRAME:025662/0001 Effective date: 20110114 Owner name: SEAGATE TECHNOLOGY LLC, CALIFORNIA Free format text: RELEASE;ASSIGNOR:JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT;REEL/FRAME:025662/0001 Effective date: 20110114 Owner name: SEAGATE TECHNOLOGY INTERNATIONAL, CALIFORNIA Free format text: RELEASE;ASSIGNOR:JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT;REEL/FRAME:025662/0001 Effective date: 20110114 Owner name: MAXTOR CORPORATION, CALIFORNIA Free format text: RELEASE;ASSIGNOR:JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT;REEL/FRAME:025662/0001 Effective date: 20110114 |
|
AS | Assignment |
Owner name: THE BANK OF NOVA SCOTIA, AS ADMINISTRATIVE AGENT, Free format text: SECURITY AGREEMENT;ASSIGNOR:SEAGATE TECHNOLOGY LLC;REEL/FRAME:026010/0350 Effective date: 20110118 |
|
AS | Assignment |
Owner name: SEAGATE TECHNOLOGY LLC, CALIFORNIA Free format text: TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENT RIGHTS;ASSIGNOR:WELLS FARGO BANK, NATIONAL ASSOCIATION, AS COLLATERAL AGENT AND SECOND PRIORITY REPRESENTATIVE;REEL/FRAME:030833/0001 Effective date: 20130312 Owner name: EVAULT INC. (F/K/A I365 INC.), CALIFORNIA Free format text: TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENT RIGHTS;ASSIGNOR:WELLS FARGO BANK, NATIONAL ASSOCIATION, AS COLLATERAL AGENT AND SECOND PRIORITY REPRESENTATIVE;REEL/FRAME:030833/0001 Effective date: 20130312 Owner name: SEAGATE TECHNOLOGY INTERNATIONAL, CAYMAN ISLANDS Free format text: TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENT RIGHTS;ASSIGNOR:WELLS FARGO BANK, NATIONAL ASSOCIATION, AS COLLATERAL AGENT AND SECOND PRIORITY REPRESENTATIVE;REEL/FRAME:030833/0001 Effective date: 20130312 Owner name: SEAGATE TECHNOLOGY US HOLDINGS, INC., CALIFORNIA Free format text: TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENT RIGHTS;ASSIGNOR:WELLS FARGO BANK, NATIONAL ASSOCIATION, AS COLLATERAL AGENT AND SECOND PRIORITY REPRESENTATIVE;REEL/FRAME:030833/0001 Effective date: 20130312 |
|
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20150708 |