WO1991003583A1 - Procedes de depot de couches de couverture sur des substrats de metaux anodisables et produits obtenus - Google Patents

Procedes de depot de couches de couverture sur des substrats de metaux anodisables et produits obtenus Download PDF

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Publication number
WO1991003583A1
WO1991003583A1 PCT/CA1990/000287 CA9000287W WO9103583A1 WO 1991003583 A1 WO1991003583 A1 WO 1991003583A1 CA 9000287 W CA9000287 W CA 9000287W WO 9103583 A1 WO9103583 A1 WO 9103583A1
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Prior art keywords
metal
deposited
substrate
electroless
pore
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PCT/CA1990/000287
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English (en)
Inventor
Dan Fern
Christopher James Hanthorn
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Alcan International Limited
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Application filed by Alcan International Limited filed Critical Alcan International Limited
Priority to DE69008359T priority Critical patent/DE69008359T2/de
Priority to EP90912713A priority patent/EP0490914B1/fr
Priority to AT9090912713T priority patent/ATE104703T1/de
Publication of WO1991003583A1 publication Critical patent/WO1991003583A1/fr

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    • 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
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
    • C23C28/345—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one oxide layer
    • 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
    • C23C18/1653—Two or more layers with at least one layer obtained by electroless plating and one layer obtained by electroplating
    • 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
    • C23C18/18—Pretreatment of the material to be coated
    • C23C18/1803—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces
    • C23C18/1848—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces by electrochemical pretreatment
    • 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
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/32—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer
    • C23C28/322—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer only coatings of metal elements only
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
    • C25D11/08—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing inorganic acids
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/18—After-treatment, e.g. pore-sealing
    • C25D11/20—Electrolytic after-treatment
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/18—After-treatment, e.g. pore-sealing
    • C25D11/24—Chemical after-treatment
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/18—After-treatment, e.g. pore-sealing
    • C25D11/24—Chemical after-treatment
    • C25D11/246—Chemical after-treatment for sealing layers

Definitions

  • This invention is concerned with improvements in or relating to methods for depositing metal coatings on substrates of anodisable metals, such as aluminum and its anodisable alloys, and to the products of such methods.
  • anodisable metals such as aluminum and its anodisable alloys
  • Review of the Prior Art The deposition of metals on a substrate, usually steel or aluminum, is a well-developed art.
  • Plating on less easily oxidized metals such as steel is relatively routine, involving for example the deposition of a layer of copper directly on the steel substrate, followed in succession by a thick "semi-bright” nickel layer, a thinner "bright” nickel layer, and an even thinner finish layer of chromium; the chromium is semi-transparent and the bright appearance is actually provided by the bright nickel layer seen through the finish chromium layer.
  • Plating on anodisable metals, such as aluminum and its anodisable alloys is considerably more difficult owing to their relative ease of oxidation, and the consequent inevitable presence of an oxide coating which must be removed if adequate adhesion of the deposited layers to the underlying metal substrate is to be obtained.
  • the substrate surface is immersed in a suitable zincate or stannate solution, usually of the sodium salt, together with other additions that have been found in practice to increase the appearance and adhesion of the coatings.
  • the zinc or tin atoms respectively displace aluminum atoms at the surface, in the process removing the oxide layer, to result in an adherent zinc or tin layer on which other layers, for example copper followed by nickel and chromium can be deposited.
  • Both of these processes are relatively expensive and are therefore mainly used on expensive commodities.
  • the stannate immersion processes are reported to provide better anti-corrosion performance and adhesion of the resultant coatings, but are the more expensive of the two because of the more expensive components and longer processing times.
  • a new method of depositing metal on a surface of a substrate of an anodisable metal including the steps of: a) ano ising the substrate at the said surface to produce a porous anodised layer of thickness from about 0.5 to about 50 micrometres; b) electrolytically depositing pore-filling metal into the pores to adhere to the walls thereof; and c) continuing the deposition of pore-filling metal by electroless deposition to fill the pores to the required extent.
  • the electroless deposition is continued until a coating of metal of thickness in the range about 0.5 to 3 micrometres is deposited on the surface of the anodised layer.
  • new products comprising anodisable metal substrates of which a surface consists of a porous anodized layer of thickness of about 0.5 to about 50 micrometres, the porous layer having electrolytically deposited in the pores thereof pore-filling metal which adheres to the walls thereof, and having electroless deposited pore-filling metal deposited in the pores on the electrolytically deposited metal
  • Figure 1 is a cross-section through the surface and adjacent portion of an aluminum substrate, through the porous anodised layer formed thereon by sulfuric acid anodising, and through the various layers of metal that have been deposited on the anodised layer; ⁇
  • Figure 2 is a cross-section to a much enlarged scale of the small portion 2 of Figure 1, showing the anodised layer and the immediately adjacent metal layers;
  • Figure 3 is the same cross-section as that of Figure 2, through a substrate in which the anodised layer is formed by phosphoric acid anodising.
  • Figure 1 is a cross-section through an aluminum substrate 10 at the upper surface of which there has been formed by acid anodising a layer 12 of aluminum oxide, a portion of which, together with the immediately adjacent portions of the substrate and deposited metal layers, are shown to a larger scale in Figure 2.
  • This particular anodising employs sulfuric acid which produces elongated narrow pores 14 (not seen in Figure 1), and in accordance with this invention at least the bottom portions of the pore walls have had applied thereto by electrolytic deposition a layer of adherent pore-filling metal 16 (also not seen in Figure 1).
  • the electrolytically deposited metal is found initially to deposit principally at the bottoms of the pores and the immediately adjacent parts of the side walls, and the resultant coatings or layers then grown progressively in thickness upwards in the pores as more metal is deposited. It is also found initially that discontinuous patches 17 of the metal are deposited on the side walls in what appears at present to be a random manner. After sufficient metal has been electrolytically deposited the filling of the pores is continued using electroless deposited metal 18 until, in this embodiment, they are completely filled and a continuous support layer has been formed over the entire surface of the anodised layer 12. In this embodiment cobalt is used as the initial electrolytically deposited metal 16 and 17, while electroless nickel is employed for the metal 18. The deposition of metal layers is continued to provide a semi-bright nickel layer 20, a bright nickel layer 22 and a tri-chrome finish layer 24.
  • the invention thus employs the electrolytic deposition of pore filling metal to apply an initial "seed" coating to the bottom wall portion of each pore and to at least the lower portion of the side wall of each pore. It is found that such an electrolytically deposited metal coating adheres very well to the anodised material, and the subsequently electroless deposited metal adheres very well to the electrolytically deposited metal, whereas metals deposited by electroless processes directly on aluminum oxide do not adhere well and result in lower strength metal coatings.
  • Electroless coating processes have the advantage that they are more efficient than electrolytic processes in filling the pores and result in more dense or compact coatings, and the processes of the invention enable advantage to be taken of this property while overcoming the potential problem of insufficient adherence of the electroless deposited metal to the anodised layer.
  • the acid most widely used for anodising is sulfuric acid because of its ready availability and lower cost, although phosphoric, oxalic and chromic acids, and mixtures of these and other acids, can also be used.
  • the anodised layer is inherently porous in structure because of the manner of its formation, and a typical structure of a layer 12 obtained by sulfuric acid anodising of the aluminum substrate 10 is illustrated by Figure 2, while that obtained by anodising with phosphoric acid is illustrated by Figure 3.
  • the horizontal surfaces of the layers are shown as flat, but in practice they will be seen to be highly irregular even at quite low magnification.
  • Figure 1 illustrates an embodiment in which an anodised layer 12 of aluminum oxide (Al-O has been produced of about 5 micrometres (50,000 Angstroms) thickness, typically by use of sulfuric acid at about 20°C and of about 165g/litre or 15% by weight concentration, employing an anodising voltage of about 15-20 volts for 10 minutes.
  • Al-O aluminum oxide
  • the porous structure obtained is relatively uniform, although highly idealised as shown in Figure 1 for convenience in drawing, and typically the pores 14 will be found to average 0.015 micrometre (150 Angstroms) in transverse dimension, spaced on average about 0.024 micrometre (240 Angstroms) from one another.
  • the bottoms of the pores do not end at the surface of the aluminum substrate, but instead they are on average spaced about 0.015 micrometre (150 Angstroms) from that surface to form a continuous non-porous barrier layer 26 of the relatively non-conductive aluminum oxide, the thickness of this layer depending principally directly on the value of the anodising voltage. Usually with sulfuric acid anodising this thickness averages about 0.0010 to 0.0014 micrometre (10 to 14 Angstroms) per volt. It may be noted that references herein and in the literature to pore sizes, etc. are usually made in Angstroms, while references to thicknesses are made in micrometres, merely to avoid the need to refer to large numbers or small fractions, 1 micrometre being equal to 10,000 Angstroms.
  • Metal deposition processes may use either alternating current or direct current, or a combination thereof.
  • A.C. depostion is usually much slower than the equivalent D.C. current and D.C. is therefore preferred if speed is important.
  • D.C. has a greater tendency to cause disruption of the coating especially with the narrow pores characteristic of sulfuric acid anodising.
  • modified A.C preferably one in which a predetermined negative-going D.C. has been superimposed on the A.C.
  • Such a system avoids the disruption that would be produced by a pure D.C. current.
  • A.C. produces metal deposition owing to the rectification characteristic of the aluminum oxide, but as the thicknesses of the coatings increase such unmodified A.C.
  • deposition gives poorer pore penetration and slower deposition rates.
  • the D.C. component is therefore increased to the maximum level that does not cause disruption.
  • This method of deposition is disclosed for example in U.S. Patent No. 4,226,680, assigned to Alcan Research and Development Limited, the disclosure of which is incorporated by this reference; these processes have now become known as the Alcan "ANOLOK" (Trade Mark) processes.
  • Other modified A.C. systems are also possible; for example, another system offsets the A.C. waveform in a manner that will produce an effective negative bias, while a further way is to increase the amplitude of the negative portion of the waveform relative to that of the positive portion, which again has the same effect.
  • the processes of the invention are applicable generally to anodisable metals, their alloys and composites; whether rolled, pressed, cast or wrought.
  • Cast metals are generally less dense and more porous in structure than the corresponding rolled, pressed or wrought product.
  • Attempts to use only electroless deposition, or only electrolytic deposition, directly on the anodised surface of a cast material have not been as successful as the processes of the invention because of this higher porosity and because of the usual higher silicon content (e.g. 7-12%) of such metals.
  • the more porous metal structure results in anodised layers of lower strength and quality, and electrolytic deposits are more adversely affected by the anodic layer quality than are electroless layers, it is believed because of entrapment of some of the silicon in the barrier layer which interferes with the normal flow of electrons in the deposition current.
  • layers applied by direct electroless deposition are generally poorly adherent to the already lower strength anodised layer.
  • Suitable substrate metals in addition to aluminum and its anodisable alloys, are magnesium and its anodisable alloys.
  • Metals suitable for the electrolytic deposition of the initial "seed" layer are cobalt, nickel, zinc, copper, tin and palladium.
  • the substrate is aluminum or an alloy thereof cobalt has been found to be particularly suitable for electrolytic deposition and nickel for electroless deposition. It is found that as the thickness of the electrolytic layers within the pores increases a point may be reached at which the adhesion to the aluminum begins to decrease, and this then sets an upper limit at which the electrolytic deposition should be stopped and replaced by the electroless deposition.
  • the electrolytic deposition can be discontinued earlier depending upon the other parameters of the particular process. It is found that the thickness of the initial seed coatings, as measured from the bottom of the pores, correlates well with the apparent colour of the substrate surface as seen by an observer, and the table below shows a specific correlation that is obtained when the anodised layer has been produced by sulfuric acid anodising is 5 micrometres thick, and the electrodeposited metal being cobalt. The thickness of the electrolytically deposited metal is most expeditously expressed
  • each pore is about 30% filled in volume with the electrolytically deposited metal, leaving the remaining 70% to be filled with the electroless deposited metal.
  • Nickel is found to produce approximately the same colour correlation as cobalt. Copper produces a range of different colours extending from pink through light maroon and dark maroon to black. Tin requires a is obtained.
  • the table refers to sulfuric acid anodising; the same principle applies with phosphoric acid anodising but the colours obtained are slightly different.
  • the amount of electroless applied metal that is deposited in the pores will of course depend upon the required properties and intended use of the resultant product, and for some applications the pores may not need to be completely filled: from about 6% to about 60% of complete filling may be all that is required. Thus, while a useful range for the electrolytic deposition is about 3% to about 30%, a useful range for the electroless deposition is also from about 3% to the remainder required to fill the pores to the required extent.
  • the electroless deposition can simply be continued until a final layer (over the anodised layer) of adequate thickness is obtained, the usual range for such an application being from about 50 micrometres to about 75 micrometres. More usually the electroless deposition is continued until it forms a support layer of adequate thickness over the entire surface of the anodised layer, as illustrated by Figures 1 and 2, the usual values being from about 0.5 micrometres to about 3 micrometres, more preferably in the range 1-2 micrometres. Thereafter, a finish layer (for example chromium) may be applied over the support layer, with or without the provision of one or more intermediate layers between the support and finish layers.
  • a finish layer for example chromium
  • the invention is particularly applicable to substrates anodised with sulfuric acid and the like in that the compact deposition characteristic of the subsequent electroless deposition works well with the narrow pores obtained with this and similar systems, whereas the less dense deposition of the electrolytic methods works better with wider pores such as are obtained with phosphoric acid and similar systems. Nevertheless, the dual deposition processes of the invention can be applied to such large pore systems and Figure 3 shows an anodised layer 12 of aluminum oxide (Al-O- of about 2 micrometres (20,000 Angstroms) thickness that typically will be produced on substrate 10 using phosphoric acid at about 20°C and of about 109g/litre or 10% by weight concentration, employing an anodising voltage of about 50-60 volts for 10 minutes.
  • Al-O- aluminum oxide
  • the pores 14 themselves are of much larger transverse dimension to give a much lower length/width ratio (20:1 in this example), and they are much more widely spaced apart at an average value of about 0.07 micrometres (700 Angstroms).
  • the barrier layer is thicker because of the higher voltage used; e.g. 60 volts gives a layer of about 700 Angstroms thickness.
  • a phosphoric acid anodised layer is found to be particularily advantageous with cast materials, and it has been found for example that for cust aluminum such as is used for automotive wheels the adhesion of the final coating/s was increased by al least 50% upon use of phosphoric acid in place of sulfuric acid for the anodising.
  • a suitable test for adhesion is to cut the finished part throught the substrate and coatings and then to attempt to lift or peel the coating away from the substrate by use of a sharp knife edge; it was found possible with this test to peel the coatings from sulfuric acid anodised substrates with various degrees of difficulty depending on the processing conditions, but not possible to peel it from prosphoric acid anodised substrates.
  • anodised layer before plating introduces the possibility, if desired, of a reduction in the thickness of the subsequent plated layers with consequent cost savings.
  • the anodising processes described employing acid baths in the temperature range 20-35°C are usually characterised as “conventional” anodising, but “hard” anodising processes can also be employed for the invention, the usual bath temperature being in the range 3-7°C; such hard anodised layers are usually thicker than the conventional anodised layers. Further reductions in the subsequent layers therefore are possible by using a thicker and/or stronger anodic film such as that produced using these lower temperature anodising processes, particularly low temperature sulfuric acid anodising.
  • the electroless layer being the support layer for further deposits, which can be thinner than those normally previously used.
  • the anodised layer 10 can be of thickness in the range 0.5 - 50 micrometres, usually in the range 1-10 micrometres, preferably in the range 2-6 micrometres, and more preferably 3-5 micrometres, with a thickness of 5 micrometres being usually commercially suitable.
  • the electroless-deposited pore-filling material need not form a support coating of more than about 2 micrometres thickness and excellent results can be obtained with the application of a single thin finish coating of chromium over the support layer.
  • the preferred electroless deposited metal is nickel. Metals other than nickel, such as cobalt, tin or copper, can also be used. Because of the thin coatings that are employed it is preferred in some processes to pre-treat the surface of the anodisable metal to obtain a very smooth surface; this can be a "macro" treatment by buffing and/or a "micro” treatment of chemical or electro-brightening.
  • the finished chromium layer if provided preferably is of thickness in the range of 0.2-0.3 micrometres.
  • Example 1 The invention is further illustrated by the following specific examples: Example 1
  • the process is employed to provide a bright finishing procedure for articles such as cast aluminum automotive wheels, giving a simulation of the appearance of bright chrome or stainless steel, and includes the following steps. 1.
  • the aluminum substrate consisting for example of cast alloys A356 or A413, or forge grade material, is pre-treated by cleaning with appropriate alkaline and/or acid solutions, or is pretreated by mechanical buffing. 2.
  • the pretreated substrate is then subjected to a conventional sulfuric acid anodising treatment using acid of 15% concentration by weight at 21°C for 10 minutes and at 15 V.D.C.
  • the anodised substrate has the initial "seed” electrolytic coating of cobalt applied using a cobalt-based
  • ANOLOK (trade mark) electrolyte as disclosed in U.S. Patent No. 3,616,309 at 21°C and 12.5 V.A.C., with or without up to 4 V.D.C. bias.
  • the electrolytic deposition proceeds for a period of about 30 seconds to about 10 minutes, preferably for about 30-60 seconds, depending upon the colour to be obtained.
  • a pore-filling coating of nickel is then applied by immersion in an electroless nickel solution (Harshaw "Alpha 103B” - trade mark) for about 10-20 minutes at pH4.7 and temperature 93°C, thus completely filling the pores and forming a support coating of about 0.5 to about 3.0 micrometres thickness.
  • the support layer is coated with an electrolytically-deposited semi-bright layer of nickel of about
  • the semi-bright layer is coated with a bright layer of nickel of about 10 micrometres thickness using Harshaw "SUPREME” (trade mark) bright solution at pH4.0; temperature 66°C; current density 4A/dm and period 10 minutes.
  • the example is completed by electrolytically depositing a trichrome finish layer using Harshaw "TRI-CHROME
  • the substrate will be rinsed in known manner which need not be detailed here. It may be noted that in this and the other examples described a cyanide or hexavalent chromium bath is not used, which is environmentally desirable.
  • Example 1 In the process of Example 1 the cobalt-based electrolyte employed to deposit the initial layer is replaced with a copper-based electrolyte comprising for example 35g/l of CuS0 4 .5H 2 0; 20g/l MgS0 4 .7H 2 0 and 5g/l H 2 S0 4 at pH 1.3 and 21°C.
  • Example 3 In the process of Example 1 the cobalt-based electrolyte employed to deposit the initial layer is replaced with a tin-based electrolyte comprising for example lOg/1 of SuS0 4 and 20g/l of H 2 S0 4 at pH 1.3 and 21°C.
  • Example 4 In the process of Example 1 the cobalt-based electrolyte employed to deposit the initial layer is replaced with a conventional Watt's nickel-based electrolyte comprising for example 240g/l of NiS0 4 .6H 2 0; 60g/l of iCl 2 .6H 2 0 and 45g/l of H 3 B0 3 at pH 4.5 and 21°C.
  • a conventional Watt's nickel-based electrolyte comprising for example 240g/l of NiS0 4 .6H 2 0; 60g/l of iCl 2 .6H 2 0 and 45g/l of H 3 B0 3 at pH 4.5 and 21°C.
  • Example 5 Example 5
  • Example 1 the cobalt-based electrolyte employed to deposit the initial layer is replaced with a palladium-based electrolyte comprising for example a 10 ml/litre "PALLAMERSE” (trade mark) aqueous solution of Technic Inc.
  • PALLAMERSE trade mark
  • This process is particularly suited for articles with a simulated stainless look for exterior application and preferably employs alloy AA-7029 as the substrate.
  • Example 6
  • Example 8 To obtain articles with a simulated appearance of stainless steel and for interior applications a substrate of cast alloy AA-5657 or AA-6463, for example, is subjected to the processes of any one of examples 1 through 5 with the omission of the deposition of the semi-bright nickel layer.
  • Example 8 To obtain articles with a simulated appearance of stainless steel and for interior applications a substrate of cast alloy AA-5657 or AA-6463, for example, is subjected to the processes of any one of examples 1 through 5 with the omission of the deposition of the semi-bright nickel layer.
  • Example 8 To obtain articles with a simulated appearance of stainless steel and for interior applications a substrate of cast alloy AA-5657 or AA-6463, for example, is subjected to the processes of any one of examples 1 through 5 with the omission of the deposition of the semi-bright nickel layer.
  • Example 8 To obtain articles with a simulated appearance of stainless steel and for interior applications a substrate of cast alloy AA-5657 or AA
  • Example 9 To obtain machine parts and articles suitable for other engineering applications the anodising and electrolytic deposition steps of any one of examples 1 through 5 are followed by a nickel electroless deposition step in which the deposition period is about 30 minutes to about 120 minutes, as required, to give layers of about 10.0 micrometres to about 40.0 micrometres thickness.
  • Example 9 To obtain machine parts and articles suitable for other engineering applications the anodising and electrolytic deposition steps of any one of examples 1 through 5 are followed by a nickel electroless deposition step in which the deposition period is about 30 minutes to about 120 minutes, as required, to give layers of about 10.0 micrometres to about 40.0 micrometres thickness.
  • Example 9 Example 9
  • a substrate of an alloy such as AA-5005 is subjected to the anodising, initial electrolytic plating and electroless plating steps of any one of examples 1 through 5, followed by the deposition of semi-bright nickel for a reduced period of about 10 to about 20 minutes, and the deposition of black chrome by the step of example 6.
  • Example 10 Bright aluminum plated composite articles are prepared from a substrate of composite material AA-6061 (incorporating 10% by weight of aluminum oxide) using the plating procedure of any one of examples 1 through 5.
  • Example 11 A substrate of aluminum cast alloy A413 (including about 12% by weight silicon) is subjected to phosphoric acid anodising using acid of 109 g/L concentration (10%) at 21°C; the anodising is begun at 60 VDC for 30 minutes and is then ramped down to approximately 18 VDC for about 0.5 minutes.
  • the electrolytically deposited metal is cobalt using the composition of example 1 at 12.5 VAC for one minute. This is followed by electroless nickel deposition for 20 minutes, semi-bright nickel deposition for 30 minutes; bright nickel deposition for 10 minutes, and tri-chro e deposition for 5 minutes, again employing the materials, etc. of example 1.
  • the resultant bright inished product exhibited excellent adhesion to the castings.

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  • Engineering & Computer Science (AREA)
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  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrochemistry (AREA)
  • Inorganic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
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Abstract

On décrit de nouveaux procédés de dépôt de couches métalliques sur des substrats de métaux anodisables tels que l'aluminium et ses alliages. Les couches sont déposées directement sur une couche poreuse anodisée qui a été produite à la surface du substrat. Du métal bouche-pores est d'abord déposé par électrolyse dans les pores et le métal se dépose initialement sur le fond et les parties inférieures des parois latérales; normalement jusqu'à ce que les pores soient entre 3 % et 30 % remplis. Ensuite, le dépôt de métal est poursuivi par un procédé sans courant jusqu'à ce que les pores soient remplis au niveau souhaité, et normalement jusqu'à ce qu'une couche de support ait été déposée sur toute la surface de la couche anodisée. D'autres couches métalliques peuvent ensuite être déposées sur la couche de support, soit par des procédés sans courant soit par des procédés catalytiques. Des couches anélectrolytiques à épaisseur considérable (jusqu'à 75 micromètres) peuvent être déposées avec succès. Les nouveaux produits de ces procédés comprennent un substrat en métal anodisable dont l'épaisseur est comprise entre environ 0,5 et environ 50 micromètres; les pores de la couche anodisée contiennent un dépôt catalytique de métal bouche-pores, et un dépôt catalytique de métal bouche-pores déposé sur la couche de métal déposé par électrolyse. Le métal catalytique peut constituer la dernière couche, ou d'autres couches peuvent être déposées par dessus afin de former le produit final. Le métal à dépôt électrolytique interposé assure une adhésion améliorée au matériau anodisé par rapport au métal à dépôt catalytique direct.
PCT/CA1990/000287 1989-09-05 1990-09-05 Procedes de depot de couches de couverture sur des substrats de metaux anodisables et produits obtenus WO1991003583A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE69008359T DE69008359T2 (de) 1989-09-05 1990-09-05 Verfahren zur ablagerung von deckschichten auf anodisierbaren metallsubstraten und dadurch erhaltene produkte.
EP90912713A EP0490914B1 (fr) 1989-09-05 1990-09-05 Procedes de depot de couches de couverture sur des substrats de metaux anodisables et produits obtenus
AT9090912713T ATE104703T1 (de) 1989-09-05 1990-09-05 Verfahren zur ablagerung von deckschichten auf anodisierbaren metallsubstraten und dadurch erhaltene produkte.

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CA610,259 1989-09-05
CA000610259A CA1341327C (fr) 1989-09-05 1989-09-05 Methodes de deposition de revetements de finition sur des elements metalliques se pretant a l'anodisation, ainsi que les produits qui en derivent

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WO1991003583A1 true WO1991003583A1 (fr) 1991-03-21

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JP (1) JP2945472B2 (fr)
AU (1) AU6287090A (fr)
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DE (1) DE69008359T2 (fr)
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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2695653A1 (fr) * 1992-09-17 1994-03-18 Rieger Franz Metallveredelung Bain pour le prétraitement de métaux légers.
WO1999018635A1 (fr) * 1997-10-03 1999-04-15 Hirel Connectors Inc. Douille de connecteur electroconductrice et resistant a la corrosion
WO1999043869A2 (fr) * 1998-02-26 1999-09-02 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Procede pour produire un revetement de protection contre la corrosion et systeme en couches pour substrats en metal leger
DE19831370A1 (de) * 1998-07-13 2000-01-27 Fraunhofer Ges Forschung Verfahren zur Beschichtung von Körpern aus Leichtmetallen oder Leichtmetallegierungen mittels Plasmaunterstützung
EP1688683A1 (fr) * 2005-01-06 2006-08-09 Fenis Teknik Ürünler A.S. Collecteur solaire léger et de rendement élevé, fait de papier d'aluminium avec une surface selective
WO2009032567A3 (fr) * 2007-08-28 2009-11-12 Alcoa Inc. Substrats d'alliage d'aluminium résistants à la corrosion et leurs procédés de fabrication
US8309237B2 (en) 2007-08-28 2012-11-13 Alcoa Inc. Corrosion resistant aluminum alloy substrates and methods of producing the same
US8927392B2 (en) 2007-11-02 2015-01-06 Siva Power, Inc. Methods for forming crystalline thin-film photovoltaic structures
WO2016162201A1 (fr) * 2015-04-09 2016-10-13 Franz Rieger Metallveredlung Procédé de dépôt d'une couche protectrice sur des pièces en aluminium
CN115341169A (zh) * 2021-05-14 2022-11-15 北京小米移动软件有限公司 表面处理方法

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EP1914330A4 (fr) * 2005-06-17 2010-03-03 Univ Tohoku Structure de film de protection d élément métallique, composant métallique employant une structure de film de protection, et équipement de fabrication de semi-conducteur ou d'affichage à écran plat employant une structure de film de protection
KR101100858B1 (ko) 2009-09-28 2012-01-02 포항공과대학교 산학협력단 연료 전지용 세퍼레이터와 이의 제조 방법 및 이를 포함하는 연료 전지 스택
KR102502436B1 (ko) * 2016-08-17 2023-02-22 씨러스 매터리얼즈 사이언스 리미티드 경합금 상에 얇은 기능성 코팅을 생성하는 방법

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EP0215950A1 (fr) * 1985-02-06 1987-04-01 Fujitsu Limited Procede de formation d'une pellicule composite d'aluminium

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S. Wernick et al.: "The Surface Treatment of Aluminium and its Alloys", vol. 1, 5th edition, 1987, Finishing Publications Ltd, (Teddington, Middlesex, GB), pages 329-330 *

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2695653A1 (fr) * 1992-09-17 1994-03-18 Rieger Franz Metallveredelung Bain pour le prétraitement de métaux légers.
BE1008295A5 (fr) * 1992-09-17 1996-04-02 Rieger Franz Metallveredelung Bain pour le pretraitement de metaux legers.
WO1999018635A1 (fr) * 1997-10-03 1999-04-15 Hirel Connectors Inc. Douille de connecteur electroconductrice et resistant a la corrosion
US6217737B1 (en) 1997-10-03 2001-04-17 Hirel Connectors Inc. Method for forming a corrosion-resistant conductive connector shell
WO1999043869A3 (fr) * 1998-02-26 1999-12-29 Fraunhofer Ges Forschung Procede pour produire un revetement de protection contre la corrosion et systeme en couches pour substrats en metal leger
WO1999043869A2 (fr) * 1998-02-26 1999-09-02 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Procede pour produire un revetement de protection contre la corrosion et systeme en couches pour substrats en metal leger
US6703135B1 (en) 1998-02-26 2004-03-09 Fraunhofer-Gesellschaft Zur Fordering Der Angewandten Forschung E.V. Method for producing a corrosion protective coating and a coating system for substrates made of light metal
DE19831370A1 (de) * 1998-07-13 2000-01-27 Fraunhofer Ges Forschung Verfahren zur Beschichtung von Körpern aus Leichtmetallen oder Leichtmetallegierungen mittels Plasmaunterstützung
WO2000004209A2 (fr) * 1998-07-13 2000-01-27 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Procede pour le revetement de corps en metaux legers ou en alliages de metaux legers au moyen d'un procede active par un plasma
WO2000004209A3 (fr) * 1998-07-13 2000-04-27 Fraunhofer Ges Forschung Procede pour le revetement de corps en metaux legers ou en alliages de metaux legers au moyen d'un procede active par un plasma
EP1688683A1 (fr) * 2005-01-06 2006-08-09 Fenis Teknik Ürünler A.S. Collecteur solaire léger et de rendement élevé, fait de papier d'aluminium avec une surface selective
WO2009032567A3 (fr) * 2007-08-28 2009-11-12 Alcoa Inc. Substrats d'alliage d'aluminium résistants à la corrosion et leurs procédés de fabrication
US7732068B2 (en) 2007-08-28 2010-06-08 Alcoa Inc. Corrosion resistant aluminum alloy substrates and methods of producing the same
US8309237B2 (en) 2007-08-28 2012-11-13 Alcoa Inc. Corrosion resistant aluminum alloy substrates and methods of producing the same
US8927392B2 (en) 2007-11-02 2015-01-06 Siva Power, Inc. Methods for forming crystalline thin-film photovoltaic structures
WO2016162201A1 (fr) * 2015-04-09 2016-10-13 Franz Rieger Metallveredlung Procédé de dépôt d'une couche protectrice sur des pièces en aluminium
DE102015105449B4 (de) 2015-04-09 2019-01-17 Rieger Metallveredlung GmbH & Co. KG Verfahren zum Aufbringen einer Schutzschicht auf Aluminiumteile
CN115341169A (zh) * 2021-05-14 2022-11-15 北京小米移动软件有限公司 表面处理方法

Also Published As

Publication number Publication date
DE69008359T2 (de) 1994-08-04
EP0490914A1 (fr) 1992-06-24
DE69008359D1 (de) 1994-05-26
JP2945472B2 (ja) 1999-09-06
AU6287090A (en) 1991-04-08
EP0490914B1 (fr) 1994-04-20
JPH05503316A (ja) 1993-06-03
ES2052269T3 (es) 1994-07-01
CA1341327C (fr) 2001-12-18

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