CA2137288A1 - Durable surface coating and coating process - Google Patents
Durable surface coating and coating processInfo
- Publication number
- CA2137288A1 CA2137288A1 CA 2137288 CA2137288A CA2137288A1 CA 2137288 A1 CA2137288 A1 CA 2137288A1 CA 2137288 CA2137288 CA 2137288 CA 2137288 A CA2137288 A CA 2137288A CA 2137288 A1 CA2137288 A1 CA 2137288A1
- Authority
- CA
- Canada
- Prior art keywords
- recited
- further characterized
- substrate
- coating layer
- coated article
- 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.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/34—Sputtering
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/0021—Reactive sputtering or evaporation
- C23C14/0036—Reactive sputtering
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
- C23C14/0676—Oxynitrides
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physical Vapour Deposition (AREA)
Abstract
Hard durable surface coatings comprising the elements Ti, Al, V, O, N and optionally Y and Mo are useful as surface coatings applied to machine tools and the like. The coatings are applied via three-electrode, cathodic sputtering methods wherein a biasing electrode (24) is maintained at a lesser polarity than the substrate-anode (20, 22) to aid in eliminating impurities from the coating.
Description
WO 93/24316 ~ 1 3 7 2 8 8 PCI`/US93/05269 : ` "
DURABLE S_FACE COATINGS AND COATING PROCES S
Field of the Invention The present invention pertains to thin, durable surface coatings and processes for providing such coatin~s on the surfaces of machine tools and the like.
Backqround of the Invention Machine tools are required to perform a variety of forming and material removal processes. For e~ample, such tools are commonly used to repetitively perform cutting, punching, chipping, milling, reaming, drilling, and other functions. Dies are used commonly in forming and punching operations. ~`
Tools wear constantly upon use and must be repaired or replaced often depending upon the severity and frequency of usage. In order to improve hardness, wear resistance, and toughness properties, these tools may be surface coated with a hard TiC, A1203, TiN, etc. layer. Coating methods vary from Chemical Vapor Deposition (CVD) methods to arc plasma spraying to various Physical Vapor Deposition Methods tPVD) including sputtering and electron beam evaporation.
I Recently~TiN coatings on high speed steel tooling have proven effective in improving tool hardness and wear properties. TiN coatings are now commonly used on the surfaces of gear cutters, gear-shaper cutters, drills, SUBSTITUTE SHEET
~li3 i ~JV
W093/24316 PCT/US93/ ~ 9 reamers, taps, chasers, spade-drill blades, broaches, saw blades and for other tools. These coatings are provided by evaporative and sputtering methods in which atoms, ions and~or neutral or charged clusters from a titanium source (i.e., target) in a vacuum chamber are ejected onto ~he tools that are positioned in the chamber proximate an anode. Inert `
gas such as argon is admitted to the evacuated chamber and, upon creation of an electrical field in the chamber, serves as a source of excited plasma ions which bombard the target to dislodge the target (i.e., coating) material. Nitrogen is also admitted into the evacuated chamber and serves as a reactive gas which, along with the Ti materials ejected from the target, forms the desired TiN coating on the tool. -Typica~Ily, the process is a line-of-sight type operation in `
.
which the ejected Ti particles traverse the chamber in a ` ;
straight line, requiring rotation of the tools in the chamber ;
:
to provide a uniform coating thereover.
Although TiN surface coatings have provided ~ ;
significant improvement in machine tool life, there remains a need to provide machine tool surface coatings which -outperform TiN coatings in wear resistance and in heat -~
resistance. `~
Of further importance is the need to provide improved coatings in a process in which the formation of undesirable impurities such as carbon particles, sodium, potassium and calcium, in the coating is inhibited. `~
, , ~
SUBSTITUTE SHEET
W093~24316 2 1 3 7 2 8 8 PCT/US93/0~269 Additionally, there is a need to provide a simplified coating process in which the need to rotate the -~
substrates during the process to attain coating uniformity is eliminated.
Summary of the Invention In accordance with the invention, hard, durable titanium containing coatings are provided on the desired substrate by a cathodic sputter coating process that is operated under controlled process parameters. Briefly, the desired substrates, such as tools, airfoîls, turbine blades, etc. are loaded onto a stationary jig that is placed within the sputter chamber.
Three electrode cathodic sputtering is conducted in the chamber with a biasing electrode provided as the third ~;;
elec~rode. A titanium alloy target, as explained in more detail hereinafter, is positioned in the chamber and serves as the cathode. The target substantially surrounds the substrates in the chamber. In accordance with conventional cathodic sputtering techniques, the stationary jig and associated substrates are charged as the anode, with a potential difference of from about 500-lOOOV e~isting between target cathode and anodic substrate. The chamber is evacuated to vacuum pressure of between about 10~l Torr. to 10-3 Torr.
SUBSTITUTE SHEET
WO93/24316 ~ 3 ~ ~ 8 PCT/US93/~6 An inert gas, pre~erably argon or ~enon, is backfilled into the evacuated chamber to serve as a source for formation of e~cited plasma ions upon creation of an electrical field in the chamber. These ions, in accord with conventional sputtering techniques, strike the target to dislodge atomic or molecular coating species therefrom.
In an especially unique aspect of the invention, both nitrogen and oxygen are admitted into the chamber -substantially concurrently to serve as reactive gases for formation of the desired coating on the anodic substrates, this being done in a non-magnatron DC sputter system. In -contrast, conventional coating processes use only one or the `;
other of these elements to form a coating on the desired -~
substrate ~ref. U.S. Pat. Nos. 4,714,660; 4,871,434 and ;~
4,973,338).
ImproYed sputtering also results from a biasing electrode whose potential is maintained at from -22 to -23V
relative to the anodic substrates. Although applicant is not to be bound to any particular theory of operation, it is thought that the electrical field between the anode and less positively charged biasing electrode provides for a-second or "mini" sputtering in the assembly in which impurities, such as c'arbon particles, sodium, potassium and calcium which would otherwise incorporate into the coating, will eject from the anode and migrate to the bias electrode.
. ~ .
~.~
SUBSTITUTE SHEET `~
'.
W093/24316 ~ 1 3 7 X ~ 8 PCT/US93/~5269 ;~......
The invention will be further described in conjunction with the appended drawings and detailed description.
Description of the ~rawinqs Fig. l is a schematic sectional diagram of a three-electrode sputtering chamber used in accordance with the invention;
Fig. 2 is a schematic depiction of the anode and biasing electrode of the sputtering chamber; and Fig. 3 is a cross-sectional view of a substrate ~ ;
coated in accordance with the invention.
Detailed DescriPtion of the Preferred Embodiment Turning now to the drawings and specifically to Fig. -l thereof, there is shown a sputter ion plating assembly 2.
Assembly 2 is preferably Model GLO-TINE 24X36 Abar-Ibsen, from Abar-Ibsen Company but could also be any other commercially available ionic sputter chamber assembly provided it is capable of achieving or can be modified to attain the sputter coating process parameters that are detailed herein. Assembly 2 comprises a vacuum vessel 4 and lid 6 which together provide a sealed environment within for provision of viacuum conditions necessary for the sputtering operation. A Cathodic target 8a, 8b, 8c is provided in the assembly and, as shown, is shaped to substantially surround ~,`;
SUBSTITUTE SHEET
W093/24316 ~1 3 7 2 8 8 PCT/US93/U~9 - 6 - ~
substrates 22 that are disposed on stationary mount 20 fitted through lid 6 of the assembly. The cathodic target comprises relati~ely spaced apart inner and outer cylindrical wafl liners 8a and 8b, respectively, and a circular bottom wall liner 8c, all formed from titanium alloy, as described ;~
below. The inner cylinder 8a is placed on the bottom wall ~;-liner 8c in the center of the outer cylinder liner 8b which is closely surrounded by the vacuum vessel 4. The spacing of the cylinders from each other is dependent on the size of the substrate to be deposited and is arranged to form a circular opposing cathode and to maintain the substrate in the middle of the negative glow region of the glow discharge and not in ~-the cathode-fall region.
Heating elements 10 are provided for heating the ~`~
gaseous environment, thereby suppressing homogeneous nucleation of particles of the material in the gaseous environment. Homogeneous nucleation occurs readily at hiqh concentrations of vapor species within an ambient gaseous ~`
environment and is to be avoided, as disclosed in U.S. Pat.
No. 4,236,994. Its occurrence gives the deposited material a ~'t'~
porous, friable and columnar structure characteristic. Y;`
Cooling fans (not shown) or other equivalent means are used to cool the vessel. Biasing electrode 24 is positioned`above mount 20.
Vacuum connection 12 communicates with the interior of assembly 2 to provide the vacuum conditions required for SUBSTITUTE SHEET ~;`
., W093/24316 PCT/US93/0i269 `i `~'~37~8~ :~
the coating operation. Gas lines 16 and 18 provide a source for entry of the desired inert gas, preferably argon, that is necessary to form the e~cited ion plasma cloud necessary for sputter coating. Gas lines 16 and 18 also serve as entry ports for the reactive gases, oxygen and nitrogen, respectively. Alternatively, a common entry port for all three gases could readily be provided.
The assembly is operated as a three-electrode sputter coating apparatus in which the target 2 serves as the cathode, with the mount 20 and associated substrate 22 charged with a positive D.C. current of from about +500 -+lOOOV to serve as the anod~. I have found that maintenance of biasing electrode 24 at from -22 to -23V less than the voltage of anode mount 20 provides enhanced coating in that impurities which may otherwise coat onto the substrate are not normally formed thereon. A potential difference of -22.6V is most preferred. Further, use of the biasing electrode tends to provide increased toughness micronodular `
coating structures compared to unbiased coatings. The target 8 is preferably maintained at ground but a negative voltage -potential could also be imparted thereto. -In accordance with the invention, target 8 is composed of either Ti-6 Al-4V alloy or Ti-8 Al-l Mo-lV
alloy. The former alloy is presently preferred based on preliminary testing. Both of these alloys can be purchased SUBSTITU~E SHEEl 2 1 3 7 2 8 8 ` P~T~US93/~-~69 ~
from a variety of sources, including Titanium Alloys, Pittsburgh, PA. The target materials are rolled and machined into the desired shape for use as targets 8 in the assembly. -~
Workpieces or substrates 22 are preferably cleaned prior to operation of the sputtering coating process. In ~-this regard, any one or more conventional cleaning processes, ~-`
includinq alkaline cleaning, electrolytic cleaning, emulsion cleaning, solvent cleaning, acid cleaning, pickling, abrasive blast cleaning and salt bath descaling can be employed.
! " ~ ` .
The cleaned substrates 22 are then loaded onto the `-stationary mount 20 that serves as an anode in the process.
One surprising aspect of the invention is that adequate throw or carry of the coating material is provided such that the coating will substantially uniformly coat over the substrate " ,~:
without requirement of rotating the substrates 22.
A vacuum of from about 10~1 to 10-3 Torr. is provided in the enclosure. Preferably, a vacuum of 10-~
Torr. is provided. This low pressure or ~soft" vacuum is ~`~
thought primarily responsible for the aforementioned e~cellent ~throwU or carry of the sputtered coating ` -~
particles. The envelopment of the substrates by the target also aids in this phenomenon.
`I During sputtering, argon is fed to the assembly within a range of from 300-460 SCCM, with 425 SCCM being a ' preferred feed rate. Initially, nitrogen is fed to the ', .
.
: ' SUBSTlTUTE SHEET
. WO93/24316 ~ 3 7 2 8 8 PCT/US93/05269 .
enclosure with oxygen feed commencing within about 1/2 hour and continuing concurrently with the nitrogen feed~ The nitrogen is fed to the enclosure within a range of about 12.5 to 13.5 SCCM with o~ygen feed rates being maintained at from about 10 to 14 SCCM. The molar ratio of ogygen:nitrogen fed into the enclosure may range from about 1:1 to about 1.25:~. -Preferably, the two reactive gases are both fed at 13.1 SCCM
resulting in a slight molar excess of o~ygen relative to nitrogen. The sputtering process proceeds for about 5-8 hours. ~.
The sputtered coatings of the invention show significant improvement over prior art TiN coatings in regard to.heat and wear r.esistance of cutting tools coated thereby.
Accordingly, at present, the processes and coatings.of the invention are used to coat toolings and other parts in which :~
heat, abrasion and shear resistance are important. The substrates 22 can be composed of a plurality of different metals ranging from a wide variety of steels, stainless steelsj titaniums, carbides and inconel-type alloys and ceramics such as A12O3, SiN and SiO2. Although the substrates are preferably to be used ultimately as machine ~
tooling products, including dies and gears, other substrates thatlmay be beneficially coated in accordance with the invention include turbine blades, airfoils, etc.
SUBSTITUTE SHEET
`~ :
WQ93~24316 PCT/US93/~P--~69 ::
~137288 1o - : :~
The preferred Ti-6 Al-4V alloy target has the ~:~
following composition. ~:
N .012 (percentages given by weight) C ~ O 1 O ~ 12E3 ~ s Fe .18 Ti 90.06 "~
Al 5.9 V 3.7 .~:
H 80 ppm ~.`
Y less than 50 ppm `~:
As to the Ti-8 Al-l Mo-lV target material~ this has ~.
the following composition:
N .015 C . 01 - ' ~, O .125 :
H .125 Ti 89.175 Al 8.0 V 1.25 Mo 1.25 When the above target materials are sputtered in .
conjunction with the conjoint use of both N2 and 2 as reactive gases, thin, durable coatings on the order of 2.0 x 10-5 to 8.0 x 10-5 inches in thickness are formed. In fact, ::.
pxeliminary results in connection with one test run indicate i.
that the coating thickness was 6.5 x 10-5. .
Coatings resulting from sputter coating with the .j above targets and reactive gases may be described as including the elements Ti, Al, V, Y, O and N, with Mo also :
being present when the Ti-8 Al-l Mo-lV target material is `:
used. ;~
'.'.:' ' ::
SUBSTITUTE SHFET ;
WO93/24316 ~,1 3 7 2 8 8 PCT/US93/0~269 ~
- 1 1 - , ;
When the preferred Ti-6 Al-4V target is used, Ti, Al, and V are present in o~ide or nitride form. The formula Ti v AlO2N is used for simplification. Similarly, when the Ti-8 Al-l Mo-lV target is used, Ti, Al, and Mo are present in o~ide or nitride form. The formula Ti V Mo AlO2N is used for simplification.
Turning now to Fi~. 2, there is schematically shown substrate 22 and ~ias electrode 24 during sputtering. Since the bias electrode 24 is maintained at from -22 to -23V
lesser potential than the substrate ~e.g., anode) 22, a -Umini'' or second sputtering causes the e~cited Ar plasma to impinge upon substrate 22, dislodging impurities, such as C, Na, K, and Ca therefrom and provides a dense equia~ nodular microstructure.
Fig. 3 illustrates substrate 22, here shown as a drill bit, coated on its surface, with a uniform thin, layer of coating 26 thereover. Coating 26 has a thickness of from 2.0 x 10-5 to 8.0 x 10-5 inches.
The following table is illustrative of the increased longevity of tools coated with the above-described Ti V AlO2N
material over identical tools coated with a conventional TiN
material.
TOOL I WORK MATERIAL PIECES MACHINED
OR OPE~ATIONS PERFORMED
BEEORE RESHARPENING
TiN Ti V AlO2N
CO~T _ COAT
INSERT CAST IRON 134 402 ~`
(TNMG-432) ~UBS~ITU~E 8HEE~
W093/24316 ~1 37 2 8 8 PCT/US93/0~69 (TNMG-432A) CUTTER
SHAPER CAST IRON 39 1~1 CUTTER ~
END MILLS 4140 100 175 `.
~3/16") INSERT CAST IRON 150 1817 `~
(VNMP-33lA) ` ~ ~ ;
(ROUND) ` `
HOBB 8620 3Q 120 `~
DRILL ` 86`20 175 800: .
~TAP : ~ 1018 Rod 1500 10, 870 20 OSG)~
While~tbis~invention has been described with respect `to pa ~i~cul:a~r;embodiments thereof, it is apparent that .~
numerous~othe~r~forms and modifications of the invention will '.'`'`
bè obvious to those skilled in the art. The appended claims !~
~and~ this invention~gener~all:y~should be construed to cover all ,such~obvio:us~`forms~ and~modifications which are within the ,`~,`,' 8pir~i,t and;~scope~o:~the~invent~ion. ~ ~ : -'`.,;
'1'`,`' .
~ ~ . .... ~,.
" .., SUBSTITUTE SHEET i ^`
. - . .
DURABLE S_FACE COATINGS AND COATING PROCES S
Field of the Invention The present invention pertains to thin, durable surface coatings and processes for providing such coatin~s on the surfaces of machine tools and the like.
Backqround of the Invention Machine tools are required to perform a variety of forming and material removal processes. For e~ample, such tools are commonly used to repetitively perform cutting, punching, chipping, milling, reaming, drilling, and other functions. Dies are used commonly in forming and punching operations. ~`
Tools wear constantly upon use and must be repaired or replaced often depending upon the severity and frequency of usage. In order to improve hardness, wear resistance, and toughness properties, these tools may be surface coated with a hard TiC, A1203, TiN, etc. layer. Coating methods vary from Chemical Vapor Deposition (CVD) methods to arc plasma spraying to various Physical Vapor Deposition Methods tPVD) including sputtering and electron beam evaporation.
I Recently~TiN coatings on high speed steel tooling have proven effective in improving tool hardness and wear properties. TiN coatings are now commonly used on the surfaces of gear cutters, gear-shaper cutters, drills, SUBSTITUTE SHEET
~li3 i ~JV
W093/24316 PCT/US93/ ~ 9 reamers, taps, chasers, spade-drill blades, broaches, saw blades and for other tools. These coatings are provided by evaporative and sputtering methods in which atoms, ions and~or neutral or charged clusters from a titanium source (i.e., target) in a vacuum chamber are ejected onto ~he tools that are positioned in the chamber proximate an anode. Inert `
gas such as argon is admitted to the evacuated chamber and, upon creation of an electrical field in the chamber, serves as a source of excited plasma ions which bombard the target to dislodge the target (i.e., coating) material. Nitrogen is also admitted into the evacuated chamber and serves as a reactive gas which, along with the Ti materials ejected from the target, forms the desired TiN coating on the tool. -Typica~Ily, the process is a line-of-sight type operation in `
.
which the ejected Ti particles traverse the chamber in a ` ;
straight line, requiring rotation of the tools in the chamber ;
:
to provide a uniform coating thereover.
Although TiN surface coatings have provided ~ ;
significant improvement in machine tool life, there remains a need to provide machine tool surface coatings which -outperform TiN coatings in wear resistance and in heat -~
resistance. `~
Of further importance is the need to provide improved coatings in a process in which the formation of undesirable impurities such as carbon particles, sodium, potassium and calcium, in the coating is inhibited. `~
, , ~
SUBSTITUTE SHEET
W093~24316 2 1 3 7 2 8 8 PCT/US93/0~269 Additionally, there is a need to provide a simplified coating process in which the need to rotate the -~
substrates during the process to attain coating uniformity is eliminated.
Summary of the Invention In accordance with the invention, hard, durable titanium containing coatings are provided on the desired substrate by a cathodic sputter coating process that is operated under controlled process parameters. Briefly, the desired substrates, such as tools, airfoîls, turbine blades, etc. are loaded onto a stationary jig that is placed within the sputter chamber.
Three electrode cathodic sputtering is conducted in the chamber with a biasing electrode provided as the third ~;;
elec~rode. A titanium alloy target, as explained in more detail hereinafter, is positioned in the chamber and serves as the cathode. The target substantially surrounds the substrates in the chamber. In accordance with conventional cathodic sputtering techniques, the stationary jig and associated substrates are charged as the anode, with a potential difference of from about 500-lOOOV e~isting between target cathode and anodic substrate. The chamber is evacuated to vacuum pressure of between about 10~l Torr. to 10-3 Torr.
SUBSTITUTE SHEET
WO93/24316 ~ 3 ~ ~ 8 PCT/US93/~6 An inert gas, pre~erably argon or ~enon, is backfilled into the evacuated chamber to serve as a source for formation of e~cited plasma ions upon creation of an electrical field in the chamber. These ions, in accord with conventional sputtering techniques, strike the target to dislodge atomic or molecular coating species therefrom.
In an especially unique aspect of the invention, both nitrogen and oxygen are admitted into the chamber -substantially concurrently to serve as reactive gases for formation of the desired coating on the anodic substrates, this being done in a non-magnatron DC sputter system. In -contrast, conventional coating processes use only one or the `;
other of these elements to form a coating on the desired -~
substrate ~ref. U.S. Pat. Nos. 4,714,660; 4,871,434 and ;~
4,973,338).
ImproYed sputtering also results from a biasing electrode whose potential is maintained at from -22 to -23V
relative to the anodic substrates. Although applicant is not to be bound to any particular theory of operation, it is thought that the electrical field between the anode and less positively charged biasing electrode provides for a-second or "mini" sputtering in the assembly in which impurities, such as c'arbon particles, sodium, potassium and calcium which would otherwise incorporate into the coating, will eject from the anode and migrate to the bias electrode.
. ~ .
~.~
SUBSTITUTE SHEET `~
'.
W093/24316 ~ 1 3 7 X ~ 8 PCT/US93/~5269 ;~......
The invention will be further described in conjunction with the appended drawings and detailed description.
Description of the ~rawinqs Fig. l is a schematic sectional diagram of a three-electrode sputtering chamber used in accordance with the invention;
Fig. 2 is a schematic depiction of the anode and biasing electrode of the sputtering chamber; and Fig. 3 is a cross-sectional view of a substrate ~ ;
coated in accordance with the invention.
Detailed DescriPtion of the Preferred Embodiment Turning now to the drawings and specifically to Fig. -l thereof, there is shown a sputter ion plating assembly 2.
Assembly 2 is preferably Model GLO-TINE 24X36 Abar-Ibsen, from Abar-Ibsen Company but could also be any other commercially available ionic sputter chamber assembly provided it is capable of achieving or can be modified to attain the sputter coating process parameters that are detailed herein. Assembly 2 comprises a vacuum vessel 4 and lid 6 which together provide a sealed environment within for provision of viacuum conditions necessary for the sputtering operation. A Cathodic target 8a, 8b, 8c is provided in the assembly and, as shown, is shaped to substantially surround ~,`;
SUBSTITUTE SHEET
W093/24316 ~1 3 7 2 8 8 PCT/US93/U~9 - 6 - ~
substrates 22 that are disposed on stationary mount 20 fitted through lid 6 of the assembly. The cathodic target comprises relati~ely spaced apart inner and outer cylindrical wafl liners 8a and 8b, respectively, and a circular bottom wall liner 8c, all formed from titanium alloy, as described ;~
below. The inner cylinder 8a is placed on the bottom wall ~;-liner 8c in the center of the outer cylinder liner 8b which is closely surrounded by the vacuum vessel 4. The spacing of the cylinders from each other is dependent on the size of the substrate to be deposited and is arranged to form a circular opposing cathode and to maintain the substrate in the middle of the negative glow region of the glow discharge and not in ~-the cathode-fall region.
Heating elements 10 are provided for heating the ~`~
gaseous environment, thereby suppressing homogeneous nucleation of particles of the material in the gaseous environment. Homogeneous nucleation occurs readily at hiqh concentrations of vapor species within an ambient gaseous ~`
environment and is to be avoided, as disclosed in U.S. Pat.
No. 4,236,994. Its occurrence gives the deposited material a ~'t'~
porous, friable and columnar structure characteristic. Y;`
Cooling fans (not shown) or other equivalent means are used to cool the vessel. Biasing electrode 24 is positioned`above mount 20.
Vacuum connection 12 communicates with the interior of assembly 2 to provide the vacuum conditions required for SUBSTITUTE SHEET ~;`
., W093/24316 PCT/US93/0i269 `i `~'~37~8~ :~
the coating operation. Gas lines 16 and 18 provide a source for entry of the desired inert gas, preferably argon, that is necessary to form the e~cited ion plasma cloud necessary for sputter coating. Gas lines 16 and 18 also serve as entry ports for the reactive gases, oxygen and nitrogen, respectively. Alternatively, a common entry port for all three gases could readily be provided.
The assembly is operated as a three-electrode sputter coating apparatus in which the target 2 serves as the cathode, with the mount 20 and associated substrate 22 charged with a positive D.C. current of from about +500 -+lOOOV to serve as the anod~. I have found that maintenance of biasing electrode 24 at from -22 to -23V less than the voltage of anode mount 20 provides enhanced coating in that impurities which may otherwise coat onto the substrate are not normally formed thereon. A potential difference of -22.6V is most preferred. Further, use of the biasing electrode tends to provide increased toughness micronodular `
coating structures compared to unbiased coatings. The target 8 is preferably maintained at ground but a negative voltage -potential could also be imparted thereto. -In accordance with the invention, target 8 is composed of either Ti-6 Al-4V alloy or Ti-8 Al-l Mo-lV
alloy. The former alloy is presently preferred based on preliminary testing. Both of these alloys can be purchased SUBSTITU~E SHEEl 2 1 3 7 2 8 8 ` P~T~US93/~-~69 ~
from a variety of sources, including Titanium Alloys, Pittsburgh, PA. The target materials are rolled and machined into the desired shape for use as targets 8 in the assembly. -~
Workpieces or substrates 22 are preferably cleaned prior to operation of the sputtering coating process. In ~-this regard, any one or more conventional cleaning processes, ~-`
includinq alkaline cleaning, electrolytic cleaning, emulsion cleaning, solvent cleaning, acid cleaning, pickling, abrasive blast cleaning and salt bath descaling can be employed.
! " ~ ` .
The cleaned substrates 22 are then loaded onto the `-stationary mount 20 that serves as an anode in the process.
One surprising aspect of the invention is that adequate throw or carry of the coating material is provided such that the coating will substantially uniformly coat over the substrate " ,~:
without requirement of rotating the substrates 22.
A vacuum of from about 10~1 to 10-3 Torr. is provided in the enclosure. Preferably, a vacuum of 10-~
Torr. is provided. This low pressure or ~soft" vacuum is ~`~
thought primarily responsible for the aforementioned e~cellent ~throwU or carry of the sputtered coating ` -~
particles. The envelopment of the substrates by the target also aids in this phenomenon.
`I During sputtering, argon is fed to the assembly within a range of from 300-460 SCCM, with 425 SCCM being a ' preferred feed rate. Initially, nitrogen is fed to the ', .
.
: ' SUBSTlTUTE SHEET
. WO93/24316 ~ 3 7 2 8 8 PCT/US93/05269 .
enclosure with oxygen feed commencing within about 1/2 hour and continuing concurrently with the nitrogen feed~ The nitrogen is fed to the enclosure within a range of about 12.5 to 13.5 SCCM with o~ygen feed rates being maintained at from about 10 to 14 SCCM. The molar ratio of ogygen:nitrogen fed into the enclosure may range from about 1:1 to about 1.25:~. -Preferably, the two reactive gases are both fed at 13.1 SCCM
resulting in a slight molar excess of o~ygen relative to nitrogen. The sputtering process proceeds for about 5-8 hours. ~.
The sputtered coatings of the invention show significant improvement over prior art TiN coatings in regard to.heat and wear r.esistance of cutting tools coated thereby.
Accordingly, at present, the processes and coatings.of the invention are used to coat toolings and other parts in which :~
heat, abrasion and shear resistance are important. The substrates 22 can be composed of a plurality of different metals ranging from a wide variety of steels, stainless steelsj titaniums, carbides and inconel-type alloys and ceramics such as A12O3, SiN and SiO2. Although the substrates are preferably to be used ultimately as machine ~
tooling products, including dies and gears, other substrates thatlmay be beneficially coated in accordance with the invention include turbine blades, airfoils, etc.
SUBSTITUTE SHEET
`~ :
WQ93~24316 PCT/US93/~P--~69 ::
~137288 1o - : :~
The preferred Ti-6 Al-4V alloy target has the ~:~
following composition. ~:
N .012 (percentages given by weight) C ~ O 1 O ~ 12E3 ~ s Fe .18 Ti 90.06 "~
Al 5.9 V 3.7 .~:
H 80 ppm ~.`
Y less than 50 ppm `~:
As to the Ti-8 Al-l Mo-lV target material~ this has ~.
the following composition:
N .015 C . 01 - ' ~, O .125 :
H .125 Ti 89.175 Al 8.0 V 1.25 Mo 1.25 When the above target materials are sputtered in .
conjunction with the conjoint use of both N2 and 2 as reactive gases, thin, durable coatings on the order of 2.0 x 10-5 to 8.0 x 10-5 inches in thickness are formed. In fact, ::.
pxeliminary results in connection with one test run indicate i.
that the coating thickness was 6.5 x 10-5. .
Coatings resulting from sputter coating with the .j above targets and reactive gases may be described as including the elements Ti, Al, V, Y, O and N, with Mo also :
being present when the Ti-8 Al-l Mo-lV target material is `:
used. ;~
'.'.:' ' ::
SUBSTITUTE SHFET ;
WO93/24316 ~,1 3 7 2 8 8 PCT/US93/0~269 ~
- 1 1 - , ;
When the preferred Ti-6 Al-4V target is used, Ti, Al, and V are present in o~ide or nitride form. The formula Ti v AlO2N is used for simplification. Similarly, when the Ti-8 Al-l Mo-lV target is used, Ti, Al, and Mo are present in o~ide or nitride form. The formula Ti V Mo AlO2N is used for simplification.
Turning now to Fi~. 2, there is schematically shown substrate 22 and ~ias electrode 24 during sputtering. Since the bias electrode 24 is maintained at from -22 to -23V
lesser potential than the substrate ~e.g., anode) 22, a -Umini'' or second sputtering causes the e~cited Ar plasma to impinge upon substrate 22, dislodging impurities, such as C, Na, K, and Ca therefrom and provides a dense equia~ nodular microstructure.
Fig. 3 illustrates substrate 22, here shown as a drill bit, coated on its surface, with a uniform thin, layer of coating 26 thereover. Coating 26 has a thickness of from 2.0 x 10-5 to 8.0 x 10-5 inches.
The following table is illustrative of the increased longevity of tools coated with the above-described Ti V AlO2N
material over identical tools coated with a conventional TiN
material.
TOOL I WORK MATERIAL PIECES MACHINED
OR OPE~ATIONS PERFORMED
BEEORE RESHARPENING
TiN Ti V AlO2N
CO~T _ COAT
INSERT CAST IRON 134 402 ~`
(TNMG-432) ~UBS~ITU~E 8HEE~
W093/24316 ~1 37 2 8 8 PCT/US93/0~69 (TNMG-432A) CUTTER
SHAPER CAST IRON 39 1~1 CUTTER ~
END MILLS 4140 100 175 `.
~3/16") INSERT CAST IRON 150 1817 `~
(VNMP-33lA) ` ~ ~ ;
(ROUND) ` `
HOBB 8620 3Q 120 `~
DRILL ` 86`20 175 800: .
~TAP : ~ 1018 Rod 1500 10, 870 20 OSG)~
While~tbis~invention has been described with respect `to pa ~i~cul:a~r;embodiments thereof, it is apparent that .~
numerous~othe~r~forms and modifications of the invention will '.'`'`
bè obvious to those skilled in the art. The appended claims !~
~and~ this invention~gener~all:y~should be construed to cover all ,such~obvio:us~`forms~ and~modifications which are within the ,`~,`,' 8pir~i,t and;~scope~o:~the~invent~ion. ~ ~ : -'`.,;
'1'`,`' .
~ ~ . .... ~,.
" .., SUBSTITUTE SHEET i ^`
. - . .
Claims (21)
1. In a surface coated article comprising a substrate and a coating layer on said substrate, the invention characterized by said coating layer comprising at least the elements Ti, Al, V, 0 and N.
2. The surface coated article as recited in claim 1, and further characterized by said coating layer further comprising the elements Mo and Y.
3. The surface coated article as recited in claim 1, and further characterized by said coating layer having a thickness of from 2.0 x 10-5 to 8.0 x 10-5 inches.
4. The surface coated article as recited in claim 3, and further characterized by said coating layer having a thickness of about 6.5 x 10-5 inches.
5. The surface coated article as recited in claim 1, and further characterized by said substrate comprising a machine tool.
6. The surface coated article as recited in claim 5, and further characterized by said machine tool being substantially uniformly coated over its surface by said coating layer.
7. The surface coated article as recited in claim 6, and further characterized by said machine tool being composed of a metal selected from the group consisting of steel, stainless steel, titanium, carbide and inconel alloys.
8. The surface coated article as recited in claim 1, and further characterized by said substrate being composed of a ceramic selected from the group consisting of A12O3, SiN, and SiO2.
9. The surface coated article as recited in claim 1, and further characterized by at least the elements Ti, Al and V being present in a nitride or oxide form.
10. The surface coated article as recited in claim 2, and further characterized by at least the elements Ti, Al, V
and Mo being present in a nitride or oxide form.
and Mo being present in a nitride or oxide form.
11. In a coating process for providing a coating layer on a substrate and comprising the steps of positioning the substrate proximate to an anode in a housing, providing a cathodic target in said housing, admitting an inert gas into said housing and imposing a voltage potential between said cathodic target and said anode, the invention characterized by:
a) providing a cathodic target comprising at least the elements Ti, Al and V;
b) maintaining a vacuum of from about 10-1 to 10-3 Torr. in said housing;
c) admitting N2 and O2 gases into said housing substantially concurrently; and d) forming a coating layer comprising at least the elements Ti, Al, V, O and N on said substrate.
a) providing a cathodic target comprising at least the elements Ti, Al and V;
b) maintaining a vacuum of from about 10-1 to 10-3 Torr. in said housing;
c) admitting N2 and O2 gases into said housing substantially concurrently; and d) forming a coating layer comprising at least the elements Ti, Al, V, O and N on said substrate.
12. The process as recited in claim 10, and further characterized by providing a cathodic target comprising at least the elements Ti, Al, Y, Mo and V and forming a coating layer comprising at least the elements Ti, Al, Y, V, Mo, O
and N on said substrate.
and N on said substrate.
13. The process as recited in claim 10, and further characterized by imposing a voltage potential of from about 500V to 1000V between said cathodic target and said anode.
14. The process as recited in claim 10, and further characterized by maintaining the vacuum at about 10-2 Torr.
15. The process as recited in claim 10, and further characterized by providing a bias electrode in said housing, and by imposing a voltage potential between said bias electrode and said cathodic target 22.0V to 23.0V below the voltage potential between the anode and said cathodic target.
16. The process as recited in claim 14, and further characterized by admitting oxygen and nitrogen gases into said housing in a ratio of between 1 part Oxygen:1 part Nitrogen to 1.25 parts Oxygen:1 part Nitrogen by weight.
17. The process as recited in claim 10, and further characterized by forming a coating layer between 2x10-5 inches and 8x10-5 inches in thickness on said substrate.
18. The process as recited in claim 16, and further characterized by forming a coating layer about 6.5 x 10-5 inches in thickness on said substrate.
19. The process as recited in claim 10, and further characterized by selecting the substrate from a group comprising steels, stainless steels, titanium, carbides and inconel alloys.
20. The process as recited in claim 10, and further characterized by selecting the substrate from a group comprising Al2O3, SiN and SiO2.
21. The process as recited in claim 10, and further characterized by forming the cathodic target with relatively spaced apart inner and outer cylindrical walls and by positioning the substrate between said inner and outer cylindrical walls.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US89326192A | 1992-06-04 | 1992-06-04 | |
| US07/893,261 | 1992-06-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2137288A1 true CA2137288A1 (en) | 1993-12-09 |
Family
ID=25401288
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2137288 Abandoned CA2137288A1 (en) | 1992-06-04 | 1993-06-04 | Durable surface coating and coating process |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2137288A1 (en) |
| WO (1) | WO1993024316A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1132498B1 (en) * | 2000-03-09 | 2008-05-07 | Sulzer Metaplas GmbH | Hard layer coated parts |
| CN106282939B (en) * | 2015-05-20 | 2019-06-18 | 中国科学院宁波材料技术与工程研究所 | A kind of mold coating and its preparation method and application |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4419202A (en) * | 1980-12-22 | 1983-12-06 | The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland | Metal coatings |
| CH667361GA3 (en) * | 1986-02-04 | 1988-10-14 | ||
| DE3611492A1 (en) * | 1986-04-05 | 1987-10-22 | Leybold Heraeus Gmbh & Co Kg | METHOD AND DEVICE FOR COATING TOOLS FOR CUTTING AND FORMING TECHNOLOGY WITH PLASTIC LAYERS |
-
1993
- 1993-06-04 CA CA 2137288 patent/CA2137288A1/en not_active Abandoned
- 1993-06-04 WO PCT/US1993/005269 patent/WO1993024316A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO1993024316A1 (en) | 1993-12-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5447804A (en) | Hard coating; a workpiece coated by such hard coating and a method of coating such workpiece by such hard coating | |
| Boxman et al. | Principles and applications of vacuum arc coatings | |
| US6554971B2 (en) | PVD coated cutting tool and method of its production | |
| US4402994A (en) | Highly hard material coated articles | |
| US20090252973A1 (en) | Coated body | |
| US6033734A (en) | Method of coating metallic and ceramic substrates | |
| US8702912B2 (en) | Coating process, workpiece or tool and its use | |
| US5693417A (en) | Vacuum-coated compound body and process for its production | |
| US20080273933A1 (en) | Pvd-Coated Cutting Tool Insert | |
| EP0608409B1 (en) | Surface preparation and deposition method for titanium nitride onto cast iron | |
| JPH07171706A (en) | Coating tool and cutting process | |
| EP2201154B1 (en) | Method of producing a layer by arc-evaporation from ceramic cathodes | |
| US9822438B2 (en) | Coated cutting tool and method for the production thereof | |
| JP4975906B2 (en) | Method for producing cutting tool coated with PVD aluminum oxide | |
| GB2134930A (en) | Cutting tools with wear-resistant coating of heat-resisant compounds of high -melting metals and method for manufacturing same | |
| JP2018003046A (en) | Hard film, hard film-coated tool, and film deposition method of hard film | |
| JP2012228735A (en) | Coated tool excellent in wear resistance and method for manufacturing the same | |
| JPH06346226A (en) | Improvement of life of tool and tool coated with wearproof layer | |
| CN111279011A (en) | Deposition of Al2O3And having at least one layer of Al2O3Coated cutting tool | |
| CA2137288A1 (en) | Durable surface coating and coating process | |
| WO1993024316A9 (en) | Durable surface coatings and coating process | |
| JP2020109210A (en) | Film deposition method of hard film | |
| JPS6224501B2 (en) | ||
| WO2024048306A1 (en) | Coated tool | |
| JPH07300665A (en) | Method for forming boron cementation layer and boron film on metallic base material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |