MXPA98005193A - Nozzle device-injector for deposition device using plasma de a - Google Patents

Abstract

The present invention relates to a deposition apparatus, characterized in that it comprises: a cathode, an electrically conductive cascade plate having an opening, anode having an opening that diverges in a flow direction, and a nozzle having an opening that diverges in the direction of flow and that extends from eláno

Description

NOZZLE-INJECTOR DEVICE FOR DEPOSITION DEVICE USING PLASMA DE ARCO TECHNICAL FIELD This invention relates to deposition of protective coatings by arc plasma on various substrates such as glass. quartz. metal or metallized materials and plastics; and very particularly to a combined nozzle-i nozzle device for directing the flow of a plasma to inject reagents into the plasma for high-speed deposition of transparent coatings that are resistant to abrasion »UV absorbers or IR reflectors.

BACKGROUND OF THE INVENTION The technological importance of thin films has led to the development of a variety of deposition methods. Chemical vapor deposition (DQV) produces a solid film on a substrate surface by thermal activation and reaction of gaseous reagent surfaces containing the desired constituents of the film. The energy required for pyro! Hoisting reagents is provided by heating the substrate. For reasonable reaction rates, the substrate is heated to relatively high temperatures in the range of about 260 to 1093.3 ° C. These temperatures prevent the application of the process to heat-sensitive substrate materials. The chemical vapor deposition increased in the plasma (DQVIP) supplies energy to the reagents by means of an electric discharge in a gas that forms a plasma in the deposition chamber. Usually »the substrate is submerged in the plasma. The rate of deposition is usually low. Polycarbonate is often the material of choice in engineering for glassware and optics applications due to its high impact strength, low density, optical clarity and good processing quality. However, »the polycarbonate material is soft» lacks abrasion resistance similar to glass »and is sensitive to temperatures above approximately 148.8 ° C. Previous work has shown that a coating of silicon oxide by chemical vapor deposition increased in plasma (DQVIP) can improve the abrasion resistance of polycarbonate »qualifying it for glassware applications. However, "the earlier DQVIP technology using xylan and nitrous oxide as the precursors was slow and therefore not economical" having typical deposition rates of only 0.05 micras per minute. The organosilicon precursors were subsequently used in DQVIP for a plasma-generated abrasion-resistant polymer coating, but the deposition rate did not improve significantly. The process of this invention provides coatings and coatings that impart improved adhesion, thermal expansion compatibility, radiation protection or abrasion resistance to articles or products made by the deposition process of the invention. The deposition of said protective coatings by the plasma on high and low temperature materials in the form of sheets, films and shaped substrates can be achieved by the apparatus and methods described herein.

BRIEF DESCRIPTION OF THE INVENTION A nozzle-injector device was designed and manufactured for plasma deposition of thin film coatings using an arc torch stabilized on its wall as the plasma generator. The design of the nozzle-injector device controls the injection »ionization and reaction of the reagents, and these functions» in turn »determine the rate of deposition of the coating. the coating area »coating composition and coating quality. Using the nozzle device 11 injector of this invention with oxygen and a siloxane as the reactants, clear coatings were demonstrated at a deposition rate of about 30 microns per minute "in the center" on a polycarbonate and glass substrate. The derived coating of siloxane greatly improved the abrasion resistance of a polycarbonate substrate. Substituting appropriate organometallic reagents for the siloxane and other oxide coatings "such as zinc oxide or titanium oxide" were also deposited on a plastic substrate. Said coatings are useful as protection reagents against infrared or ultraviolet radiation. The nozzle design device of this invention combines in a single device the direction control function of a nozzle with the reagent introduction function of one or more injectors. Organosilicon compounds useful as monomers in the arc plasma deposition process using the nozzle device 11 a-injector of this invention include xylan and other silicon compounds in which at least one silicon atom is attached to at least one carbon atom or one hydrogen atom »such as s loxanes» silazanos and organos 1 icones.

DESCRIPTION OF THE INVENTION The described nozzle-injector device is suitable for use with a variety of plasma generating apparatuses such as a plasma torch of arc stabilized on its wall having at least one electrically insulated plate cooled with water located between the cathode and the anode .

Wall-stabilized multi-plate arch devices are described in U.S. Patents 4,94B, 4B5 and 4, 957,062. The multi-layered cascade arc has been used as a plasma source for making diamond-shaped carbon coatings and plasma polymerized from hydrocarbon reagents and organosides respectively. Deposition rates of a few micras per minute were reported. However, the coating area was small, a few centimeters in diameter, and the degree of material utilization was low, less than approximately 20%. Depending on the conditions, the dust or powder coatings could also have formed outside the central deposition zone. To make the coating technique practical and economical, "it is crucial to enlarge the coating area" in order to increase the deposition rate and minimize the formation of dust. The nozzle-injector device of that invention achieves these improvements. The nozzle 1 nozzle device was designed to improve the performance of the coating of arch plasma generators stabilized on its wall for use in low temperature plasma deposition and polymerization methods. Shower-type ring injectors or slot ring were constructed in the nozzle for the supply of gas or vapor reagents. The locations of the injectors affect the degree of gas ionization which affects the degree of reaction, and therefore the etch chemistry and the structure of the coating, and finally its performance. The shape and size of the nozzle-injector device also affects the degree of reaction, the coating area and the thermal load on the substrate. With a nozzle-injector device, optically clear coatings of 30 cm x 30 cm in the area were deposited at a speed of approximately 30 microns per minute in the center. Powder coatings were formed without such an injector nozzle device. The configuration of the nozzle 1 device and the structure included cylindrical and conical plasma channels and a 2-stage conical channel with a cylindrical section between them. The diverging angle of the conical channel of the nozzle 1 injector device varied from about 0 to 60 °. The opening of the plasma channel at the base of the nozzle varied from about 4 to 7 mm in diameter. Smaller diameter channels could be used to coat small objects. The length of the nozzle-injector device varied from 1.5 to 25 cm, thus controlling the volume of the area in which the reaction could take place. The nozzle 1 injector device can be a single integral construction or can be assembled from parts such as a stainless steel main body with injectors to introduce reactants to the plasma, a copper adapter for mounting the nozzle-injector device to the plasma generator and an extension fixed to the downstream end of the main body to provide an adequate volume for the reaction zone that exists within the nozzle-injector device. An injector can be built into the copper adapter for oxygen injection »and gold is deposited to the copper adapter to resist oxidation. The modular design of the nozzle-injector device allows the effect of nozzle size and gas injection position eliminates the need to separate the control and direction control units from the reagent.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross section of a plasma arc deposition system including a vacuum chamber »a plasma generator and the nozzle 1 injector device of the invention. Figure 2 is a cross-sectional view of a plasma generator and a nozzle 1 injector device according to the invention.

DESCRIPTION OF THE DRAWINGS Referring now to Figure 1, the arc plasma coating system schematically illustrated comprises a vacuum chamber reactor 1 which includes a plasma generator 2 and a plasma treatment chamber 4, B a plasma inlet G and a nozzle 1 injector 8 device. The plasma generator is provided with the plasma gas such as argon through a gas supply line 3. The injector 11 injector 8 device is provided with an oxygen supply line 12 and a pair of reagent supply lines 14 and 16 that can be operated individually or in combination. A vacuum pump system, not shown »maintains low pressure inside the plasma treatment chamber 4 through the outlet 23. The substrate to be coated 20 is supported in the plasma treatment chamber on a controlled support by temperature 22. A retractable plug 24 is adapted for manual positioning by a handle 25 or its automatic positioning between the substrate and the nozzle in the path of the plasma jet. Referring to Figure 2, the plasma is generated by an electron stream flowing from the cathode 2 to the anode cooled with water 4 through an electrically isolated plate 6 having a central gas plasma channel of divergent configuration. The device is provided with a plurality of cathodes equally spaced »only one of them shown with the number 2. The cathodes are cooled with water. The cathodes are mounted in urt cathode housing 8 which is mounted on a copper plate cooled with water 6. Plate G is electrically isolated. The cooling water channel 9 is supplied through a water line »not shown. The cooling water for the anode 4 is supplied by the water stream 12 which flows through the conduit 5 into the anode body. The vacuum within the treatment chamber is maintained in part by sealed 0-rings 15 and 15a. The plasma gas »for example» argon »is supplied to the plasma generator through the gas line 14. Oxygen is supplied to the nozzle via line 16 which communicates with a circular conduit IB and a slot injector 20 The reagent is supplied through line 1 to line 22 feeding line 24 and injection holes 26 evenly spaced. As illustrated »the nozzle has a secondary reagent supply line 30 in connection with the conduit 32 and injection holes 34. The secondary supply system can be used to feed another reactive gas or diluent gas to the activation or reaction zone inside the nozzle 1 nozzle device. The nozzle-injector device includes a diverging portion 40 for directing the plasma and reactive species to the surface of the substrate to be coated. The portion 40 may be an integral part of the nozzle unit or may be designed as a removable extension. As shown, the extension has the same degree of divergence as the part of the nozzle immediately adjacent to the anode. The extension may vary from the shape and geometry of the anode plasma channel and the adjacent portion of the nozzle-injector device, eg, having an IO. mouth widened or bell-shaped. The securing screw 7 is one of several screws used to mount the cathode housing to the plate 6 and the anode 4. The invention provides an apparatus for surface treatment and deposition of an optically clear adherent coating on a substrate surface by reagents injected into the plasma, comprising a plasma generator having one or more cathodes and at least one anode »a treatment chamber operable at subatmos eric pressures, substrate support means located within the treatment chamber to support the Substrate, vacuum pumping means communicating with the treatment chamber to evacuate the subatmospheric pressure treatment chamber »a nozzle-injector device mounted on the anode end of the plasma generator to direct the plasma jet to the substrate and to deliver the reactants to the plasma within of the nozzle-injector device. The nozzle-injector device comprises reagent delivery means for injecting reagents into the plasma as the plasma emerges from the plasma generator. The nozzle 1 nozzle device is generally tapered with the wide end facing the substrate. The degree of divergence and the length of the nozzle determine the volume enclosed within the device. This in turn determines the time available for the reaction and formation of active species that treat or coat the surface of the substrate. The reagent delivery means for injecting reagents into the plasma are located at the narrow end of the nozzle 1 injector device and include at least two separate annular injection passages and distribution means for the uniform introduction of reagents to the plasma. As usual, the nozzle-i nozzle device extends from the anode end of the plasma generator to the treatment chamber. However, the 11-in -jector nozzle device device could be mounted on the anode end of the plasma generator outside the vacuum chamber communicating with the interior of the vacuum chamber through a vacuum seal.

EXPERIMENTAL SECTION A cascade arc cooled with water was used as the plasma generator. The arc generator includes a copper anode separated from three cathodes of tungsten needle thoriated by at least one series of electrically insulated copper disks. With the argon flowing through the hole of the arc torch, a DC voltage is applied to the electrodes to generate a plasma. The plasma expands through the jetting device into a chamber at a reduced pressure maintained by a vacuum pump thus forming a plasma jet. The nozzle-i nozzle device is heated to approximately 200 ° C to prevent condensation of high boiling point organ reagents. The substrate to be coated is supported on the jet axis by means of a metal stage at a suitable working distance "for example" of approximately 15 to 70 cm from the anode. A retractable obturator is used to regulate the exposure of the substrate to the plasma. In a typical deposition procedure, the argon plasma is established with the obturator in place between the substrate and the injector nozzle device 11. Oxygen is introduced to the injector nozzle device 11 to produce an oxygen / argon plasma. The obturator was retracted and the substrate exposed to the oxygen / argon plasma for a short time before reagent containing silicon was introduced downstream from the oxygen injection site to initiate deposition. In Table 1, the effects of the nozzle-injector device on the coating area, deposition rate and Taber abrasion resistance of the coating are compared. The coatings were approximately 2 microns thick. It was found that a conical nozzle-injector device (G273, T241) is more effective for large area coatings. Without said nozzle-and-nozzle device, powder or powder coatings were generally obtained.

TABLE 1 Effect of the nozzle-injector device on the performance of the coating G273 G241 G187 G204 G147 G123 Type of injector I eat conical-conical nozzle-like "easy-to-eat" Angle diver40 40 25 25 33 50 people (grade) Sect. 1.1 3.0 cylindrical (cm) Total length 16 16 21 13.5 13.5 9.5 nozzle (crn) Alignment position 0.5 0.5 4.5 Oxygen concentration13 (cm) Siloxane feed position * 3 (cm) Distance of 25.5 25.5 33 23 38 38 work0 (c) Substrate MR7 Glass MR7-MR- PC MR5- Reacti o de Si "3 D4 TMDSO TMDSO TMDSO HMDSO HMDSO Speed of 1.0 1.0 1.5 1.5 2.0 2.0 flow of argon (1 / min) Speed of 0.8 0.8 0.8 OB 0.06-0.6 0-0.93 flow of oxygen (1 / m Speed of 0.27 O. IB O.18 O.18 0.11 0.18 flow if loxane (l / mi) 5 Position of 0.15 O.15 0.15 0.15 O.18 0.22 chamber (torr) Speed of 29 9 10 10 4 IO deposition (μm / min) Coating area 43 43 15 7.5 10 7.5 10 clear course (cm dia) \ turbidity at 3 - 7 3 6 10 1 »000 cycles (%) -15 * conical »conical-indian-conic-1-cylindrical» or conical-indian-1-arc distance to the anode ° distance between the substrate and the anode < aD4 = octameti 1 ci clotetrasi 1 oxano »TMDSO = tetramethi disiloxane» HMDSO = hexamethyl siloxane '20 • polycarbonate with hard silicone coating The working distance is the distance from the anode to the substrate D4 the flow rate was controlled keeping the temperature of the liquid constant at 80 ° C. In the particular experiments described above »the nozzle-injector device comprises a main body with two shower head type injection rings» an adapter for mounting the nozzle-injector device to the anode and injecting oxygen into the plasma »and an extended portion that expands towards the substrate. The second stage of 25 ° is a nozzle 1 injector device with an anode adapter injector that expands from 4 to 11 mm »followed by a cylindrical section with a diameter of 11 mm» and a main body that expands to 25 °. The conical section of 25 ° -10.16 cm is a nozzle device 1 the injector that expands to an angle of 25 ° completely »with an oxygen injection adapter» and a conical extension of 10.16 cm in length. The 40 ° -10.16 cm conical nozzle is a nozzle nozzle device that expands to 40 ° completely »with an anode adapter with oxygen injection and a conical extension of 10.16 cm in length. The 40 ° -10.16 cm trombone injector is a nozzle-injector device similar to the 10.16 cm and 40 ° conical except that the extension widens further using a 10.16 cm section cut from the bell of a trombone structure.

Claims (6)

NOVELTY OF THE INVENTION CLAIMS

1. - A unitary nozzle 1 device for an arc plasma deposition apparatus comprising an arc plasma generator having a plasma gas inlet, at least one cathode, an anode having an arc channel, divergent plasma, a nozzle 1 injector device mounted on the anode, said nozzle 1 injector device having a divergent channel extending from the anode, an oxygen injector for injecting oxygen into the plasma in the vicinity * of the anode , at least one reagent injector for injecting reactive gases into the plasma as the plasma expands to the divergent channel.

2. An apparatus for surface treatment and deposition of an optically clear adherent coating on a substrate surface by reagents injected into the plasma comprising a plasma generator having one or more cathodes and at least one anode, a chamber of operable treatment at subatmospheric pressures, substrate support means located within the treatment chamber to support the substrate »vacuum pump means communicating with the treatment chamber to evacuate the subatmospheric pressure treatment chamber» a nozzle device Injector mounted on the anode end of the plasma generator to direct the plasma jet to the substrate and deliver the reactants to the plasma within the boiler 1 in-jet device.

3. The apparatus according to claim 2 wherein the nozzle-injector device comprises reagent delivery means for injecting reagents into the plasma as the plasma emerges from the plasma generator.

4. The apparatus according to claim 2 »further characterized in that the injector nozzle device is conical with the wide end facing the substrate.

5. The apparatus according to claim 2 wherein the reagent supply means for injecting reagents into the plasma are located at the narrow end of the nozzle-injector device and includes at least two separate and average injection conduits. of annular distribution for uniform introduction of the reactants to the plasma.

6. The apparatus according to claim 2, wherein the nozzle-injector device extends from the anode end of the plasma generator to the treatment chamber. IB - R-E-S-U-M-E-N- ^ D-E - LA - I-NV-E-NC ___ I_Ó__N_ A nozzle 11 injector device was designed and fabricated for deposition of thin film coatings by plasma using an arc torch stabilized on its wall as the plasma generator; the design of the nozzle-i nozzle device controls the injection »ionization and reaction of the reagents, and these functions in turn determine the rate of deposition of the coating» coating area, coating composition and coating quality. JJ / ehp * elt P98 / 429