GB2455359A - Ni-PTFE composite coatings with sprayed PTFE - Google Patents
Ni-PTFE composite coatings with sprayed PTFE Download PDFInfo
- Publication number
- GB2455359A GB2455359A GB0724033A GB0724033A GB2455359A GB 2455359 A GB2455359 A GB 2455359A GB 0724033 A GB0724033 A GB 0724033A GB 0724033 A GB0724033 A GB 0724033A GB 2455359 A GB2455359 A GB 2455359A
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- Prior art keywords
- ptfe
- composite coatings
- sprayed
- nickel
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- 229920001343 polytetrafluoroethylene Polymers 0.000 title claims abstract description 145
- 239000004810 polytetrafluoroethylene Substances 0.000 title claims abstract description 142
- 238000000576 coating method Methods 0.000 title claims abstract description 89
- 239000002131 composite material Substances 0.000 title claims abstract description 80
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 180
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 91
- 239000010935 stainless steel Substances 0.000 claims abstract 3
- 229910001220 stainless steel Inorganic materials 0.000 claims abstract 3
- 239000000758 substrate Substances 0.000 claims description 38
- 238000007747 plating Methods 0.000 claims description 26
- 238000009792 diffusion process Methods 0.000 claims description 8
- 239000011159 matrix material Substances 0.000 claims description 8
- 229910000838 Al alloy Inorganic materials 0.000 claims 8
- 239000000203 mixture Substances 0.000 claims 4
- 239000000843 powder Substances 0.000 claims 4
- 229910001369 Brass Inorganic materials 0.000 claims 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims 2
- 229910000831 Steel Inorganic materials 0.000 claims 2
- 229910045601 alloy Inorganic materials 0.000 claims 2
- 239000000956 alloy Substances 0.000 claims 2
- 239000010951 brass Substances 0.000 claims 2
- 229910052804 chromium Inorganic materials 0.000 claims 2
- 239000011651 chromium Substances 0.000 claims 2
- 239000010949 copper Substances 0.000 claims 2
- 229910052802 copper Inorganic materials 0.000 claims 2
- 239000010959 steel Substances 0.000 claims 2
- 238000010438 heat treatment Methods 0.000 abstract description 9
- 239000004411 aluminium Substances 0.000 abstract description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 5
- 229910052782 aluminium Inorganic materials 0.000 abstract description 5
- 239000011248 coating agent Substances 0.000 description 10
- 239000002245 particle Substances 0.000 description 10
- 238000010348 incorporation Methods 0.000 description 8
- 238000000034 method Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000000151 deposition Methods 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 4
- 238000011068 loading method Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000004881 precipitation hardening Methods 0.000 description 4
- 238000004506 ultrasonic cleaning Methods 0.000 description 4
- XSTXAVWGXDQKEL-UHFFFAOYSA-N Trichloroethylene Chemical group ClC=C(Cl)Cl XSTXAVWGXDQKEL-UHFFFAOYSA-N 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- 238000001246 colloidal dispersion Methods 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 150000002815 nickel Chemical class 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- UBOXGVDOUJQMTN-UHFFFAOYSA-N trichloroethylene Natural products ClCC(Cl)Cl UBOXGVDOUJQMTN-UHFFFAOYSA-N 0.000 description 2
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
- B05D5/08—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain an anti-friction or anti-adhesive surface
- B05D5/083—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain an anti-friction or anti-adhesive surface involving the use of fluoropolymers
- B05D5/086—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain an anti-friction or anti-adhesive surface involving the use of fluoropolymers having an anchoring layer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
- B05D5/08—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain an anti-friction or anti-adhesive surface
- B05D5/083—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain an anti-friction or anti-adhesive surface involving the use of fluoropolymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
- B05D5/02—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain a matt or rough surface
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
-
- 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
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/1601—Process or apparatus
- C23C18/1633—Process of electroless plating
- C23C18/1646—Characteristics of the product obtained
- C23C18/165—Multilayered product
-
- 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
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/1601—Process or apparatus
- C23C18/1633—Process of electroless plating
- C23C18/1689—After-treatment
- C23C18/1692—Heat-treatment
-
- 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
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/31—Coating with metals
- C23C18/32—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2202/00—Metallic substrate
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2202/00—Metallic substrate
- B05D2202/10—Metallic substrate based on Fe
- B05D2202/15—Stainless steel
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2202/00—Metallic substrate
- B05D2202/20—Metallic substrate based on light metals
- B05D2202/25—Metallic substrate based on light metals based on Al
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2350/00—Pretreatment of the substrate
- B05D2350/60—Adding a layer before coating
- B05D2350/65—Adding a layer before coating metal layer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2506/00—Halogenated polymers
- B05D2506/10—Fluorinated polymers
- B05D2506/15—Polytetrafluoroethylene [PTFE]
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
- B05D3/0254—After-treatment
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Electrochemistry (AREA)
- Chemically Coating (AREA)
Abstract
Nickel-PTFE composite coatings have been produced using sprayed polytetraflouroethylene (PTFE). The heat treatment at 400{C with the sprayed PTFE layer on top of electroless nickel plated aluminium or stainless steel has been used to achieve Ni-PTFE composite coatings. These coatings have a microhardness value of 800 HV. Composite coatings having similar hardness values have also been produced using electroplated nickel in place of electroless nickel.
Description
Ni-PTFE COMPOSITE COATINGS WITH SPRAYED PTFE
Field of the invention
This invention relates to the use of sprayed PTFE with electroless as well as electroplated nickel to produce Ni-PTFE composite coatings.
Background
Ni-PTFE composite coatings have thus far been produced by dispersing fine PTFE particles in electroless nickel plating bath and sometimes agitating them using ultrasonic energy for a uniform dispersion. The PTFE particles get embedded in the nickel plating during the plating process and subsequent heat treatment, to below PTFE decomposition temperatures, produces Ni-PTFE composite coatings with some PTFE diffused into the nickel matrix.
Use of sprayed PTFE In the present invention, we use an alternative method of supplying PTFE for incorporation into nickel to form the composite coatings. The PTFE used in this invention, is supplied by a sprayed layer of PTFE deposited on top of the electroless nickel plating on a suitable substrate.
The advantage of a sprayed layer is the relative ease of availability of uniformly distributed PTFE material over the entire surface of the electroless nickel for incorporation into the composite coatings. This avoids the need of arduous fine tuning of the bath formula and the plating conditions with the contents of the PTFE and surfactants.
This also avoids the need of an ultrasonic agitation system which is sometimes employed to improve the uniformity of dispersion of the PTFE particles in the plating bath.
One further advantage while using wet sprayed PTFE is the access to finer particle size in the colloidal dispersion of the material as compared to the particles which are dispersed in a plating bath.
Ni-PTFE composite coatings and method of producing the same There is provided, in accordance with the present invention, a substrate onto which Ni-PTFE composite coatings are deposited. This substrate may, conveniently, be aluminium.
The substrate is cleaned using a solvent based ultrasonic cleaning system. A thin layer of nickel is then deposited onto this clean substrate using electroless nickel plating.
This electroless nickel layer may, conveniently, be 10 im thick.
On top of this nickel layer, a thin layer of PTFE is deposited by wet spraying.
The substrate is then heated to 100-120°C to dry off the PTFE.
The substrate is finally taken to 400°C and held at this temperature for some time.
This time may, conveniently, be 15 minutes.
Using electroless nickel for Ni-PTFE composite coatings As deposited electroless nickel is an amorphous coating. The heat treatment at 400°C causes its complete crystallisation and the formation of Ni-PTFE composite coating as a result of the creation of a diffusion layer where some PTFE diffuses into the nickel matrix. The creation of this diffusion layer considerably improves the friction and wear properties of the composite coatings as has been observed with the Ni-PTFE composite coatings produced using plating bath dispersed PTFE.
In comparison with the as deposited electroless nickel coating, this heat treatment at 400°C also increases the microhardness of composite coatings mainly as a result of the precipitation hardening of nickel.
The microhardness of these Ni-PTFE composite coatings using sprayed PTFE has been measured using Shimadzu HMV2 microhardness tester at 25 gm load and 10 seconds loading time. This has been found to match the microhardness reported in case of composite coatings produced using plating bath dispersed PTFE.
Using electroplated nickel for Ni-PTFIE composite coatings The present invention also encompasses the formation ofNi-PTFE composite coatings with sprayed PTFE using electroplated nickel in place of the electroless nickel. The thickness of the electroplated nickel may conveniently be the same as that of the electroless nickel.
The electroplated nickel is a crystalline coating. Therefore, the heat treatment at 400°C produces a diffusion layer of PTFE into the nickel matrix and the precipitation hardening of the composite coatings as in case of the electroless nickel.
The microhardness of the Ni-PTFE composite coatings using electroplated nickel with sprayed PTFE has been measured as described above and found to be the same as the microhardness of the Ni-PTFE composite coatings using electroless nickel.
Example
In one embodiment of this invention, which is given by way of example, a quantity of 10 off aluminium 6082 16 substrates (40 mm long, 25 mm wide and 5 mm thick) were cleaned using trichloroethylene based ultrasonic cleaning system. Half of these substrates were coated with 10 im thickness of electroless nickel. The balance were coated with 10 tm thickness of electroplated nickel.
All of these substrates were wet sprayed with a thin layer of PTFE and dried off at 120°C in a preheated hot air oven. The substrates are then transferred to a hot air furnace and heated up to 400°C and held at this temperature for 15 minutes. With the furnace switched off, the substrates are now allowed to cool in the furnace for a minimum of 8 hours and a further 4 hours outside the furnace at the ambient temperature.
The microhardness of composite coatings in these two batches containing 5 substrates per batch is then measured using Shimadzu HMV2 microhardness tester at 25 gin load and seconds loading time. The average value of the microhardness for each batch is taken to be the value of the microhardness for that type of coating.
The microhardness of Ni-PTFE composite coatings using electroless nickel is found to be 800 HVIO.25N.
The microhardness of the Ni-PTFE composite coatings using electroplated nickel is found to be 805 HV/0.25N. This value is practically the same as its counterpart for the Ni-PTFE composite coatings with electroless nickel. This is to be expected as at 400°C the as deposited amorphous electroless nickel is completely converted into a crystalline structure. Therefore from the point of view of producing Ni-PTFE composite coatings with sprayed PTFE there is no real difference in using electroless nickel or electroplated nickel.
With the Ni-PTFE composite coatings produced using plating bath dispersed PTFE, the PTFE content of the coatings comes from the incorporation of the PTFE in the slowly depositing electroless nickel layer. Whereas the fast depositing electroplated nickel does not encourage the incorporation of enough PTFE to produce Ni-PTFE composite coatings. But with the sprayed PTFE, the electroplated nickel can also be used to produce Ni-PTFE composite coatings.
Ni-PTFE COMPOSITE COATINGS WITH SPRAYED PTFE
Field of the invention
This invention relates to the use of sprayed PTFE with electroless as well as electroplated nickel to produce Ni-PTFE composite coatings.
Background
Ni-PTFE composite coatings have thus far been produced by dispersing fine PTFE particles in electroless nickel plating bath and sometimes agitating them using ultrasonic energy for a uniform dispersion. The PTFE particles get embedded in the nickel plating during the plating process and subsequent heat treatment, to below PTFE decomposition temperatures, produces Ni-PTFE composite coatings with some PTFE diffused into the nickel matrix.
Use of sprayed PTFE In the present invention, we use an alternative method of supplying PTFE for incorporation into nickel to form the composite coatings. The PTFE used in this invention, is supplied by a sprayed layer of PTFE deposited on top of the electroless nickel plating on a suitable substrate.
The advantage of a sprayed layer is the relative ease of availability of uniformly distributed PTFE material over the entire surface of the electroless nickel for incorporation into the composite coatings. This avoids the need of arduous fine tuning of the bath formula and the plating conditions with the contents of the PTFE and surfactants.
This also avoids the need of an ultrasonic agitation system which is sometimes employed to improve the uniformity of dispersion of the PTFE particles in the plating bath.
One further advantage while using wet sprayed PTFE is the access to finer particle size in the colloidal dispersion of the material as compared to the particles which are dispersed in a plating bath.
Ni-PTFE composite coatings and method of producing the same There is provided, in accordance with the present invention, a substrate onto which Ni-PTFE composite coatings are deposited. This substrate may, conveniently, be aluminium.
The substrate is cleaned using a solvent based ultrasonic cleaning system. A thin layer of nickel is then deposited onto this clean substrate using electroless nickel plating.
This electroless nickel layer may, conveniently, be 10 im thick.
On top of this nickel layer, a thin layer of PTFE is deposited by wet spraying.
The substrate is then heated to 100-120°C to dry off the PTFE.
The substrate is finally taken to 400°C and held at this temperature for some time.
This time may, conveniently, be 15 minutes.
Using electroless nickel for Ni-PTFE composite coatings As deposited electroless nickel is an amorphous coating. The heat treatment at 400°C causes its complete crystallisation and the formation of Ni-PTFE composite coating as a result of the creation of a diffusion layer where some PTFE diffuses into the nickel matrix. The creation of this diffusion layer considerably improves the friction and wear properties of the composite coatings as has been observed with the Ni-PTFE composite coatings produced using plating bath dispersed PTFE.
In comparison with the as deposited electroless nickel coating, this heat treatment at 400°C also increases the microhardness of composite coatings mainly as a result of the precipitation hardening of nickel.
The microhardness of these Ni-PTFE composite coatings using sprayed PTFE has been measured using Shimadzu HMV2 microhardness tester at 25 gm load and 10 seconds loading time. This has been found to match the microhardness reported in case of composite coatings produced using plating bath dispersed PTFE.
Using electroplated nickel for Ni-PTFIE composite coatings The present invention also encompasses the formation ofNi-PTFE composite coatings with sprayed PTFE using electroplated nickel in place of the electroless nickel. The thickness of the electroplated nickel may conveniently be the same as that of the electroless nickel.
The electroplated nickel is a crystalline coating. Therefore, the heat treatment at 400°C produces a diffusion layer of PTFE into the nickel matrix and the precipitation hardening of the composite coatings as in case of the electroless nickel.
The microhardness of the Ni-PTFE composite coatings using electroplated nickel with sprayed PTFE has been measured as described above and found to be the same as the microhardness of the Ni-PTFE composite coatings using electroless nickel.
Example
In one embodiment of this invention, which is given by way of example, a quantity of 10 off aluminium 6082 16 substrates (40 mm long, 25 mm wide and 5 mm thick) were cleaned using trichloroethylene based ultrasonic cleaning system. Half of these substrates were coated with 10 im thickness of electroless nickel. The balance were coated with 10 tm thickness of electroplated nickel.
All of these substrates were wet sprayed with a thin layer of PTFE and dried off at 120°C in a preheated hot air oven. The substrates are then transferred to a hot air furnace and heated up to 400°C and held at this temperature for 15 minutes. With the furnace switched off, the substrates are now allowed to cool in the furnace for a minimum of 8 hours and a further 4 hours outside the furnace at the ambient temperature.
The microhardness of composite coatings in these two batches containing 5 substrates per batch is then measured using Shimadzu HMV2 microhardness tester at 25 gin load and seconds loading time. The average value of the microhardness for each batch is taken to be the value of the microhardness for that type of coating.
The microhardness of Ni-PTFE composite coatings using electroless nickel is found to be 800 HVIO.25N.
The microhardness of the Ni-PTFE composite coatings using electroplated nickel is found to be 805 HV/0.25N. This value is practically the same as its counterpart for the Ni-PTFE composite coatings with electroless nickel. This is to be expected as at 400°C the as deposited amorphous electroless nickel is completely converted into a crystalline structure. Therefore from the point of view of producing Ni-PTFE composite coatings with sprayed PTFE there is no real difference in using electroless nickel or electroplated nickel.
With the Ni-PTFE composite coatings produced using plating bath dispersed PTFE, the PTFE content of the coatings comes from the incorporation of the PTFE in the slowly depositing electroless nickel layer. Whereas the fast depositing electroplated nickel does not encourage the incorporation of enough PTFE to produce Ni-PTFE composite coatings. But with the sprayed PTFE, the electroplated nickel can also be used to produce Ni-PTFE composite coatings.
Claims (5)
- LI-Claims 1. Ni-PTFE composite coatings produced using PTFE, wet sprayed and then dried, on top of electroless nickel plating on aluminium alloy substrate which is subsequently heat treated to 400°C.2. Ni-PTFE composite coatings as claimed in claim I in which electrostatically sprayed PTFE powder is used in place of wet sprayed PTFE.3. Ni-PTFE composite coatings as claimed in claims I and 2 in which a blend of fluorocarbons is used instead of PTFE on its own.4. Ni-PTFE composite coatings as claimed in claims 1, 2 and 3 in which steel, stainless steel or other metallic substrates are used in place of aluminium alloy substrate.5. Ni-PTFE composite coatings as claimed in claims 1, 2, 3, and 4 in which electroplated nickel is used in place of electroless nickel. - 5 V..Amendments to the Claims have been filed as follows Amended Cjaims 1. Ni-PTFE composite coatings produced using PTFE, wet sprayed and then dried, on top of electroless nickel plating on aluminium alloy substrate which is subsequently heat treated to 400°C creating a diffusion layer where PTFE diffuses interstitially into the nickel atomic matrix.2. Ni-PTFE composite coatings as claimed in claim 1 in which electrostatically sprayed PTFE powder is used in place of wet sprayed PTFE.3. Ni-PTFE composite coatings as claimed in claims I and 2 in which a blend of fluorocarbons is used instead of PTFE on its own.4. Ni-PTFE composite coatings as claimed in claims 1, 2 and 3 in which metallic substrates like copper, brass, chromium or their alloys are used in place of aluminium alloy substrate.5. Ni-PTFE composite coatings as claimed in claims 1, 2, 3, and 4 in which a continuous film of electroplated nickel free from porosity, pinholes or cracks is used in place of electroless nickel. * *S 1 S * S. * 0 * SSS I S. S S.. IS S.. *.S. * S. S. SS SS* * ,LI-Claims 1. Ni-PTFE composite coatings produced using PTFE, wet sprayed and then dried, on top of electroless nickel plating on aluminium alloy substrate which is subsequently heat treated to 400°C.
- 2. Ni-PTFE composite coatings as claimed in claim I in which electrostatically sprayed PTFE powder is used in place of wet sprayed PTFE.
- 3. Ni-PTFE composite coatings as claimed in claims I and 2 in which a blend of fluorocarbons is used instead of PTFE on its own.
- 4. Ni-PTFE composite coatings as claimed in claims 1, 2 and 3 in which steel, stainless steel or other metallic substrates are used in place of aluminium alloy substrate.
- 5. Ni-PTFE composite coatings as claimed in claims 1, 2, 3, and 4 in which a continuous film of electroplated nickel free from porosity, pinholes or cracks is used in place of electroless nickel. * *S 1 S * S. * 0 * SSS I S. S S.. IS S.. *.S. * S. S. SS SS* * ,5. Ni-PTFE composite coatings as claimed in claims 1, 2, 3, and 4 in which electroplated nickel is used in place of electroless nickel. - 5 V..Amendments to the Claims have been filed as follows Amended Cjaims 1. Ni-PTFE composite coatings produced using PTFE, wet sprayed and then dried, on top of electroless nickel plating on aluminium alloy substrate which is subsequently heat treated to 400°C creating a diffusion layer where PTFE diffuses interstitially into the nickel atomic matrix.2. Ni-PTFE composite coatings as claimed in claim 1 in which electrostatically sprayed PTFE powder is used in place of wet sprayed PTFE.3. Ni-PTFE composite coatings as claimed in claims I and 2 in which a blend of fluorocarbons is used instead of PTFE on its own.4. Ni-PTFE composite coatings as claimed in claims 1, 2 and 3 in which metallic substrates like copper, brass, chromium or their alloys are used in place of aluminium alloy substrate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0724033A GB2455359B (en) | 2007-12-07 | 2007-12-07 | Ni-PTFE composite coatings with sprayed PTFE |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0724033A GB2455359B (en) | 2007-12-07 | 2007-12-07 | Ni-PTFE composite coatings with sprayed PTFE |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0724033D0 GB0724033D0 (en) | 2008-01-16 |
| GB2455359A true GB2455359A (en) | 2009-06-10 |
| GB2455359B GB2455359B (en) | 2011-09-07 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0724033A Active GB2455359B (en) | 2007-12-07 | 2007-12-07 | Ni-PTFE composite coatings with sprayed PTFE |
Country Status (1)
| Country | Link |
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| GB (1) | GB2455359B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103225098A (en) * | 2013-05-28 | 2013-07-31 | 模德模具(东莞)有限公司 | Preparation method of nickel-polytetrafluoroethylene coating |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL27209A (en) * | 1966-02-02 | 1971-01-28 | Kidde & Co Walter | Fluorocarbon coated metal surfaces |
| JPS5753277A (en) * | 1980-09-17 | 1982-03-30 | Nikken Toso Kogyo Kk | Fluororesin filmformation on surface of iron or iron alloy |
| JPS582396A (en) * | 1981-06-29 | 1983-01-07 | Seiko Epson Corp | Analog-display wrist watch |
| JPS62158026A (en) * | 1986-01-07 | 1987-07-14 | Toray Ind Inc | Heating of film made of thermoplastic resin |
| DE4215594A1 (en) * | 1991-05-16 | 1992-11-19 | Tsai Tung Hung | METHOD FOR COATING METAL COOKING UTENSILS |
| US6213168B1 (en) * | 1997-03-31 | 2001-04-10 | Therics, Inc. | Apparatus and method for dispensing of powders |
| JP3343676B2 (en) * | 1998-12-24 | 2002-11-11 | 日建塗装工業株式会社 | Composite coating of plating and fluororesin and method of forming |
| KR100468859B1 (en) * | 2002-12-05 | 2005-01-29 | 삼성전자주식회사 | Monolithic inkjet printhead and method of manufacturing thereof |
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2007
- 2007-12-07 GB GB0724033A patent/GB2455359B/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103225098A (en) * | 2013-05-28 | 2013-07-31 | 模德模具(东莞)有限公司 | Preparation method of nickel-polytetrafluoroethylene coating |
| CN103225098B (en) * | 2013-05-28 | 2015-10-28 | 模德模具(东莞)有限公司 | A kind of preparation method of nickel-polytetrafluorethylecoatings coatings |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2455359B (en) | 2011-09-07 |
| GB0724033D0 (en) | 2008-01-16 |
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