JPH02185993A - Covering of finishing metal layer on surface of anode-treating metal base - Google Patents

Abstract

PURPOSE: To form a homogeneous layer having excellent adhesiveness to a base body by packing and depositing a metal into the pores of an anodically treated layer formed on the base to form a continuous supporting layer, then coating the layer with a finishing metal.

CONSTITUTION: The porous anodically treated layer having about 0.5 to 50μm thickness and about 0.005 to 0.10μm size in a transverse direction is formed on the surface of the Al (alloy) base body by subjecting this surface to an anodic treatment. The metal selected from Ni, Co, Cu, Sn and their mixtures is deposited in the pores by an AC deposition method or corrected AC deposition method so as to be completely packed therein, by which the continuous supporting layer having about 0.5 to 3μm thickness is formed on the surface of the anodically treated layer. The supporting layer is subjected to the finish metallic coating, of semi-bright Ni layer, bright Ni layer, Cr finishing layer, etc.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for applying a finish coating to a substrate made of anodizable metals such as aluminum and anodizable alloys of the metals, and to the results obtained by the method. The present invention relates to techniques for plating finished coatings of chromium on products made of aluminum, particularly aluminum and its alloys.

(Prior art and problems to be solved by the invention) Substrate (sub-5) usually made of steel or aluminum
The technology for depositing chromium and other metals suitable for finish coatings is well developed. Plating on metals that do not easily oxidize, such as steel, is relatively It is a routine operation, for example depositing a layer of steel directly on a steel substrate and then
Thick "semi-bright")
Nickel layer and thin “bright”
”) A layer of nickel and a thinner finish layer of chrome are deposited in sequence. In this case, the chrome is translucent and the shiny appearance is actually visible through the chrome finish layer. This is achieved by a shiny nickel layer.

anodizable like aluminum
Plating on el metal and anodically treatable alloys of the metal is as follows:
These metals and alloys oxidize relatively easily, resulting in the inevitable formation of an oxide layer that must be removed if the deposited layer is to adhere satisfactorily to the underlying metal substrate. Therefore, it is quite difficult. This technology is currently practiced primarily by two methods of preparing the substrate surface: zincate and stannate immersion.

That is, in such methods, the substrate surface is treated with a suitable zincate or stannate solution, usually a sodium salt, containing other additives known to enhance the appearance and adhesion of the coating. immersed. Zinc or tin atoms replace aluminum atoms at the substrate surface in the process of removing the oxide layer and provide support for other layers, for example copper and nickel forming the finishing layer or receiving a finishing layer of chromium, for example. An adhesive zinc or tin layer is deposited to form the structure. Both of these methods are relatively expensive and are therefore primarily implemented on expensive items. The stannate dipping method is reported to have good corrosion resistance and adhesion in the resulting coatings, but is expensive due to the expensive materials used and long processing times.

Furthermore, the adhesive metal coating can be applied directly to the surface of the aluminum or aluminum alloy substrate by forming a porous anodized layer on the surface of the substrate, to which the metal layer is subsequently applied. Also proposed, this anodized layer incorporates the oxide layer present on the substrate surface. Published in June 1985 [
Brating and Surface Finishing J
f”Plating &5surface Finis
"Plating on Alumin, a Review J ("Plating on Aluminium") published by D.N.S. Rushmore on pages 36 to 39 of "Hing").
um, aReview") that the anodized coating must have pores of minimum size that allow the subsequently formed coating to be mechanically "locked" or "key"l, thus ,0
．． The study reportedly found that the use of electrolytes that produce pores as large as 0.07 microns (700 angstroms) is limited. Experiments have shown that sulfuric acid or oxalic acid is often mixed with phosphoric acid, which has been found to give good results.Furthermore, the paper states that adhesion of the subsequently formed coating is primarily mechanical. , it is stated that since the cohesive strength of porous oxide coatings on metal substrates is the limiting factor, anodization should be improved to increase this cohesive strength and the strength of the oxide layer itself.Furthermore, This paper reports that the local turbulence or electrochemical potential changes assumed in the anodizing bath cause pore bifurcation, and when such a phenomenon occurs, the mechanical adhesion becomes even stronger. Although scale acid anodization/coating processes have been developed for more than 50 years, they have not been widely adopted commercially because their adhesion and gloss are about 2. it is conceivable that.

U.S. Patent No. 4.111.763 and U.S. Patent No. 4.163
．． No. 083 describes the method of anodizing the surface of aluminum or its alloy to be plated in an acid bath.
-zingl, the anodized layer is impregnated with a chemical that can pyrolyze to form an electronically conductive oxide, and the surface is heated to pyrolyze the chemical and oxidize into the pores of the anodized layer. A method of plating chromium on aluminum or its alloys in a configuration that provides an anodic coating with high ionic resistance that forms a continuous barrier layer with excellent corrosion resistance that allows the metal layers to be plated in succession by forming an object. is disclosed. The proposed chemicals are stannous chloride and orthobutyl titanate, which are associated with stannous oxide and conductive titanium oxide (Tt20a), respectively.
The surface can be further treated with titanium after plating the final coating to convert the Tl2O3 to insulating titanium dioxide (Ti203).

The object of the invention is to provide a new method for plating metal layers on substrates made of aluminum or its alloys.

SUMMARY OF THE INVENTION According to the present invention, a method is provided for applying a finishing metal layer to the surface of a substrate made of an anodizable metal. This method of depositing a finishing metal layer on the surface of an anodizable metal substrate includes: (a) anodizing the surface of the substrate to give a
It has a thickness of about 0.005 to 0.000 microns.
Transverse dimension of 10 microns
(b) forming a porous anodized layer with pores of 1.5 to 3.3 mm dimension); (C) depositing a filler metal into the holes and continuing to deposit the hole filler metal to form a continuous support layer on the surface of the anodized layer with a thickness in the range of about 0.5 to 3 microns; forming at least one finish metal coating on the support layer.

The invention further provides a method of applying a finishing metal layer to the surface of a substrate made of an anodizable metal.

This method of applying a finished metal layer to the surface of an anodizable metal substrate includes: (a) first anodizing the surface of said substrate to form a portion of a large-hole anodized layer having large pores opening to the free surface; and then anodizing to form a small pore anodized layer portion having small pores communicating with the large pores of the large pore layer portion between the large pore layer portion and the remainder of the substrate. (b) depositing a pore-filling metal on the porous anodization layer to fill the pores and supporting the pore-filling metal thereon; (c) forming at least one finish metal layer on the support layer.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described with reference to the methods of depositing various metal layers on anodized substrates and the products obtained by such methods, and with reference to the accompanying drawings, which illustrate the invention.

Sulfuric acid is the most widely used acid for porous anodizing due to its ease of labor and low cost, but phosphoric acid, oxalic acid and chromic acid and mixtures of these and other acids are also used. can also be used. Due to the manner in which it is formed, the anodized layer is inherently porous in structure;
FIG. 1 shows the general structure of a layer obtained by anodizing an aluminum substrate with sulfuric acid. In FIG. 1, the layer and the aluminum substrate each have the reference numeral 10.
and 12. In the drawings, the surfaces of the layers are shown to be flat for the sake of illustration, but in reality, even at very low magnification, these surfaces are observed to be irregular.

FIG. 1 shows an anodized layer 10 of aluminum oxide [A1.03+] approximately 5 microns (50,000 angstroms) thick. This oxide layer was formed using sulfuric acid at a concentration of about 165 g/I or 15% by weight at a temperature of about 20° C. and an anodizing voltage of about 15 to 20 volts.
This can be obtained by applying the voltage for 0 minutes. The porous structure thus obtained, although highly idealized in FIG. 1 for illustration purposes, is relatively uniform, with the pores often having an average lateral dimension of 0.05 mm. 0.015 microns (150 angstroms) and are spaced an average of about 0.024 microns (240 angstroms) apart from each other. The pores do not terminate at the surface of the aluminum substrate, but are separated from the surface by an average of about 0.015 microns (150 angstroms) and are relatively non-conductive continuous non-porous particles.
forms a barrier layer. The thickness of this layer is primarily directly influenced by the value of the anodizing voltage. For normal sulfuric acid anodization, this thickness averages about 0 per volt.
．． 0010 to 0.0014 microns (10 to 14 angstroms). In this specification and in the literature, pore sizes are typically expressed in Angstroms, while thicknesses are expressed in small fractions.
To avoid the need to mention onj, it is usually expressed in microns (fmicrometer). 1 micron is equal to 10,000 Angstroms.

Previous commercial scale implementations have shown that it is possible to form deposited metal coatings of sufficient strength and stability up to approximately 5 microns in thickness; Beyond this value, they are long and thin (i.e. with a length to width ratio of approximately 330:1 in the example shown).
Hydrogen generated in the pores tends to cause spalling of the coating, compromising its strength to the extent that it is insufficient to receive and hold a subsequently deposited metal layer. Another problem is that it is difficult to deposit hole-filling metal into elongated holes using conventional DC plating methods. Thus, the plating process creates a physical discontinuation of the anodized layer.
ption) and therefore the plated metal layer has poor adhesion.

Figure 2 shows that the temperature is about 20°C and the concentration is about 100g/! 2
anodization of aluminum oxide (AIJ3) approximately 2 microns (20,000 angstroms) thick, typically obtained by using 10% by weight phosphoric acid and applying an anodizing voltage of approximately 50 to 60 volts for 10 minutes. Layer 10 is shown. The holes themselves are significantly larger in lateral dimension and have a significantly smaller length to width ratio (20:1 in this example). Also, the average hole size is 0.
．． They are formed separated from each other by a significantly large distance of 0.7 microns (700 angstroms).

The barrier layer is thick due to the high voltage applied; for example, applying 60 volts can result in a layer approximately 700 angstroms thick. This significantly increased hole size makes it easier to plate using DC current. However, despite considerable efforts with this type of anodization, it has not been implemented on a commercial scale due to problems with adhesion and the poor appearance of the resulting coatings.

FIG. 3 shows an aluminum substrate 12 on the surface of which is formed an anodized layer 10 of aluminum oxide according to the present invention.
FIG. 4 is a cross-sectional view of FIG. A pore-filling metal, in this case semi-bright nickel, is deposited on the anodized layer to form the support layer 14;
Furthermore, layer 15 is applied to the desired thickness. In FIG. 3, layer 15 is also semi-bright nickel. A bright nickel layer 16 and a thin finishing layer 18 of chromium are applied in succession to this semi-bright nickel layer 15. Metals other than nickel can also be used, such as cobalt, tin or copper.

Referring to FIGS. 4 and 5, layer 10 includes substrate 1
2 is applied by a first anodizing step to form a first layer portion having holes 20 of relatively large lateral dimension opening into the free surface of the substrate. This first step is stopped when the corresponding layer section has reached a sufficient thickness, and then a second anodizing step is performed, in which the large holes 20
A second layer portion is formed having a hole 22 of relatively small lateral dimension opening therein, and a barrier layer 24 is formed between the second layer portion and the substrate 12 . In the example shown in FIGS. 4 and 5, the hole 20 has a lateral dimension of zero.
．． They are approximately 1.5 microns (15,000 angstroms) deep and spaced apart by a distance of approximately 0.07 microns. On the other hand, the small holes 22 in the second layer communicating with the large holes 20 have lateral dimensions of 0.015 microns (150 angstroms) and approximately 2.5 microns (25,0 angstroms).
They have a depth of 0.000 angstroms and are spaced apart from each other by a distance of approximately 0.0024 microns (240 angstroms). Such composite structures include
layer 14 without disrupting the pores and/or barrier layer.
of metal and still provide the required good adhesion between layers 10 and 14 as well as provide the required strength layer.

A preferred method of depositing the pore fill metal of layer 14 into the composite pores 20 and 22 without damaging the barrier layer is a predetermined negative-going method.
iB) Modified AC currents (modified A, C) where the DC current is preferably superimposed on the AC current.

The present invention uses one of the known systems described herein and in the claims. Such a system avoids disruption of the barrier layer caused by pure C current. However, the rectifying properties of aluminum oxide allow only AC current to deposit the metal and form a support layer sufficient for a relatively thin, e.g., 2 micron, anodic coating. For thicker coatings, such unmodified AC deposition does not provide sufficient pore penetration and the deposition rate to deposit the support layer is significantly lower. The speed and thickness are
It can be enhanced by increasing the DC component to the maximum level that does not cause discontinuation. This deposition method is used, for example, by Alkane Research and Development.
Limited (Alcan Research and
U.S. Patent No. 4. , 226.680. Other modified ACJ systems are also possible.

For example, superimposed D
The C component is obtained by negative bias for -M,
This can be increased as required, while the same effect can be obtained by reducing the positive bias. There are other systems that offset the AC waveform in a manner that provides an effective negative bias.

Yet another method of increasing the magnitude of the negative portion of the waveform relative to the positive portion has the same effect.

In a preferred method, the substrate is first anodized with phosphoric acid, with the applied anodizing voltage starting at a value typically in the high range for phosphoric acid. The anodizing voltage is reduced in this step so that at the end of the phosphoric acid anodizing a range of low values suitable for sulfuric acid anodizing is reached. This results in
Prevents the sudden application of electrical potentials that could have an adverse effect on the coating during electrolyte exchange, which is usually carried out by transferring the object from a phosphoric acid bath to a sulfuric acid bath, followed by thorough rinsing with water. can do.

Prior to plating, anodic film
The use of l allows the thickness of subsequently deposited plating layers to be reduced, if desired, resulting in cost reduction. The wall thickness is - layer thickness and/or as obtained by lowering the temperature of the sulfuric acid anodization.
or can be made even smaller by using stronger anode films. In this industry, cost reductions are particularly important for relatively expensive corrosion-resistant metals used in intermediate and final coatings. Therefore, it has become a commercially important issue to reduce the wall thickness as much as possible to obtain equivalent corrosion resistance and/or appearance.

In the method of the invention, the anodized layer 10 has a thickness in the range of 0.5 to 50 microns, usually in the range of 1 to 10 microns, preferably in the range of 2 to 6 microns, more preferably in the range of 3 to 5 microns. Wall thicknesses of 5 microns are usually suitable commercially. The pore-filling metal need not form a support coating thicker than about 2 microns, and excellent results can be obtained by forming a thin single finishing layer of chromium over the pore-filling metal layer. A preferred pore-filling metal is nickel. Since it is a thin coating layer that is employed, it may be preferable to pre-treat the surface of the anodizable metal in order to obtain a particularly smooth surface, this being done by a "macro" treatment by puff polishing and/or It can be a "macro" treatment by chemical or electronic polishing. The wall thickness of the support layer of pore-filling metal preferably ranges from 0.3 to 5 microns, preferably from 1 to 2 microns. The thickness of the chromium layer is preferably 2 to 3 microns.

This anodizing method, which uses an acid bath in the temperature range of 20 to 35° C., is usually characterized as "conventional" anodizing, although "hard" anodizing methods are also used in the present invention. The bath temperature is typically in the range of 3 to 7° C. This hard anodized layer is generally thicker than a conventional anodized layer.

Such a hard layer forms the basis of a nickel or cobalt pore-filling metal deposit, which can serve as a support layer for a further deposit, which is previously It can be made thinner than the one used.

In accordance with another aspect of the invention, a single stage sulfuric acid anodization of the surface of an anodizable substrate is followed by an AC current superimposed with a DC current or other AC deposition current to completely fill the pores with metal. A deposition process is provided in which the step of filling the anodized layer is continued until a layer of pore-filling metal of no more than about 2 microns is formed on the surface of the anodized layer. In addition to the above-mentioned U.S. Pat. No. 4,226,680, conventional methods are described in, for example, U.S. Pat. A slight partial filling of the holes with metal is then performed to obtain the desired color.

The present invention will be further explained below with reference to Examples.

In a particular embodiment of the method of the present invention, the blood vessels are pretreated, usually by cleaning with a suitable alkaline and/or acid solution, and then at a concentration of 10% by weight at a temperature of 21°C. Anodization was performed using phosphoric acid. Voltage 60V for 2 minutes
Hold at DC, then increase to 1.5 V over a period of 3 minutes.
0 to DC and held at 15VDC for 2 minutes.
The object was then rinsed with water and transferred to a sulfuric acid anodizing bath with a concentration of 15% by weight and a temperature of 21° C. and held at 15 VDC for 5 minutes. Next, for example, 240 g/β of nickel sulfate (NiSO, 7)120) and 60 g/12
of nickel chloride (NiC1□6H201, 45 g
/ (W) containing boric acid (H3BO,)
atts) The holes were deposited with nickel using a nickel bath. The bath was maintained at a pH of 4.5 and a temperature of 21°C. Using this bath and AC current, increase the voltage to 12 VAC over 1 minute, hold the voltage at 12 VAC for 2 minutes, then bias the voltage to 12 VDC and
The main deposition current was obtained by holding at 2 VAC for 8 minutes. next,
The nickel and chromium layers were deposited by any suitable conventional method.

In another method, the temperature of the phosphoric acid electrolyte is between 21 and 3
The temperature can be in the range of 5° C. and the ramp up time to 60 VDC can be in the range of 2 to 5 minutes.

Real JmJLλ Type AA6463, which is widely used in architecture.
A substrate obtained by mechanically puffing aluminum of
Anodization was carried out using wt% phosphoric acid. voltage 2
It was held at 60 VDC for minutes, then gradually decreased to 15 VDC over a period of 3 minutes, and held at 15 VDC for 2 minutes.

The object was then rinsed with water and transferred to a sulfuric acid anodization bath with a concentration of 15% by weight and a temperature of 21° C. and held at 15 VDC for 5 minutes. After a supporting layer of nickel was deposited using the bath of Example 9 below and according to the electrical specifications of Example 10, a 25 micron thick layer of electroless nickel was deposited by the method described in Example 5. It was covered.

Example 3 Type A, which is widely used in automobile bumpers
A substrate obtained by mechanically puff polishing A7029 aluminum was pretreated and anodized in the same manner as in Example 2. The nickel support layers were deposited as in Example 1O below, followed by a 40 micron thick semi-bright nickel layer, a 15 micron thick bright nickel layer and a 2 micron thick chromium layer. The layers were deposited using conventional plating techniques. The resulting product had a shiny "chrome" finish, which is desirable for such automotive applications.

1 Seed ■A Type A, as widely used in non-decorative architecture.
A substrate obtained by mechanically puff polishing A6063 aluminum was pretreated and anodized in the same manner as in Example 2. The nickel support layer was deposited as in Example 10 below, followed by a 15 micron thick bright nickel layer and a 2 micron thick chromium layer using conventional plating techniques. I arrived. The resulting product had a shiny "chrome" finish.

Example 5 A porous anodized layer IO with pore-filling metal and support layer was obtained as described in Example 1 and then subjected to electroless deposition, the metals being nickel, cobalt and copper. I chose. Electroless compositions suitable for this purpose include, for example, the Metal Finishing Tools First Guidebook and Directory Issue (Met
alFinishing, 51st Guideb
ook and Directory Issue) No. 8
N. Fieldstein, Vol. 1, 1983, pp. 468-476.

Elect
role(Autocatalyticl Pla
There are a number of them, as disclosed in the paper entitled ting'l. Because the anodized layer has greater strength and adhesion, the pore-filling metal can be formed much thicker than previously possible, up to about 25 microns, and has a specular luster suitable for decorative applications. I was able to get the finish.

Type AA6 is a general-purpose extruded material such as actual JUIDan machine material.
063 aluminum mechanically puffed substrates were pretreated with appropriate alkaline and acid cleaning solutions. Next, anodization was carried out using phosphoric acid at a concentration of io wt % and a temperature of 21 °C, and the voltage was held at 60 VDC for 2 minutes, then gradually lowered to 20 VDC over 3 minutes, and then further It was held at 20VDC for 2 minutes. Next, the object was rinsed with water and transferred to a sulfuric acid bath with a concentration of 15% by weight and a temperature of 5°C for hard anodization (hardanodis
ed), but the voltage was held at 20 VDC for 5 minutes. A support layer of nickel and a 25 micron electroless nickel layer were deposited as described in Examples 2 and 5. The resulting product had a "stainless steel" appearance and good wear resistance and was eminently suitable for engineering applications requiring hard surfaces.

After pretreatment of the aluminum substrate, it was anodized using a sulfuric acid bath with a concentration of 15% by weight and a temperature of 21'C at a voltage of 15VDC for 10 minutes to form a wall thickness of approximately 5 microns. An anodized layer was obtained. Next, this was added with the Wachnickel plating bath described in Example 1 or 100 g/ff of cobalt sulfate FCO3O-/7H20) and 40 g/1
2 c7) Boric acid (H, BO41 and 150g/f2 magnesium sulfate (MgSO4・7H20) are combined,
Plating was performed using a cobalt plating bath with a pH of 4.4. The temperature of the bath was 16°C.

Type AA5657 bright rolled aluminum substrates, such as those used commercially for glossy automotive trim, are pretreated with suitable alkaline and acid cleaning solutions before using phosphoric acid based solutions. Next, using sulfuric acid with a concentration of 15% by weight (165g/f2) and a temperature of 20'C (7), the voltage was set to 15VDC.
Anodization was carried out by holding for 4% of the time to obtain a porous anodized layer with a thickness of 2 microns. After thorough rinsing, the pores were coated with cobalt using the electrolyte of Example 6 and an AC current of 12% VAC for 5 minutes. A thin 2 micron layer of chrome was then deposited using conventional plating techniques. The resulting product had an appearance typical of stainless steel.

A type AA5252 bright rolled aluminum substrate, also used commercially for glossy automotive trim, was anodized as described in Example 8 to a thickness of 2 microns. After thorough rinsing, with the same electrical specifications as Example 8, 240g/J2 of nickel sulfate)'v
(NiS04・7H20+, 60 g/[ of nickel chloride (NiC126H2o) and 45 g/ρ of boric acid [H
Nickel was deposited in the pores using a Wachnickel bath consisting of 3BO41, pH held at 4.5 and temperature held at 21°C. Next, by conventional plating technology, 2
A micron-thin chromium layer was deposited. The obtained product is
It had an appearance that symbolized stainless steel.

1 plate±↓ Type AA6463, which is widely used in architecture.
A mechanically puffed aluminum substrate was anodized as described in Example 7 to a thickness of 5 microns for 10 minutes. After rinsing thoroughly,
The holes were deposited with nickel using a Watnickel bath as described in Example 8. An AC current is applied by increasing the voltage to 1.2 VAC over 1 minute, and this voltage is increased to 2 VAC.
hold for a minute, then negative 2VDC shift
was superimposed on the above AC voltage for 8 minutes. Additionally, a 5 micron layer of electroless nickel was deposited using conventional electroless plating techniques. The resulting product had an appearance characteristic of polished stainless steel.

A Bright Rolled Aluminum substrate of ``Futin'' LL Upper Type 5657 was bright anodized as described in Example 8 to a thickness of 5 microns for 10 minutes. After thorough rinsing, the holes were nickel deposited using a Wachnickel bath as described in Example 9.

The AC voltage is initially 1 with a negative 2VDC bias.
Set at 2HVAc, the current was gradually increased to this level over 1 minute and held at this level for 10 minutes. A 5 micron thick layer of electroless nickel was then deposited using conventional electroless plating techniques. The product obtained had the same appearance as that obtained in Example 10.

The method of the present invention is not limited to architectural, automotive, and decorative finishing applications; for example, the present invention applies a black chrome finish layer to a nickel support layer to absorb solar radiant energy. It can also be used in absorbers that selectively absorb. The method of the invention can also be used in the manufacture of magnetic disks, in which case also the nickel support layer is formed before the chromium layer is formed.

(Effects) As described above, according to the present invention, it is possible to apply the finishing layer inexpensively and easily, and since the layer is applied homogeneously without any discontinuity, the final finishing layer is It can have excellent adhesive properties.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view showing the surface and adjacent portions of an aluminum substrate and a porous anodized layer deposited on the substrate by sulfuric acid anodization, and FIG. 2 shows the porous anodized layer formed on the anodized substrate by phosphoric acid anodization. FIG. 3 is a partial cross-sectional view similar to FIG. 1 showing a porous anodized layer formed in accordance with the present invention on and adjacent to the surface of an aluminum substrate and a porous anodized layer formed in accordance with the present invention and deposited on the anodized layer. FIG. 4 is an enlarged cross-sectional view of portion 4 of FIG. 3 showing the anodized layer and its adjacent metal layer; FIG.
The figure is an enlarged cross-sectional view similar to FIG. 4. 10... Anodized layer, 12... Aluminum substrate,
14... Semi-bright nickel support layer, 15... Semi-bright nickel layer, 16... Bright nickel layer, 18... Chrome finishing layer, 20... Large pore, 22... Small pore, 24 ...barrier layer. FIG.4

Claims (27)

[Claims] (1) A method of depositing a finishing metal layer on the surface of a substrate made of an anodizable metal, wherein the surface of the substrate is anodized to have a thickness of about 0.5 to 50 microns and about 0.005 to 50 microns. forming a porous anodized layer with pores with lateral dimensions of 0.10 microns and completely filling the pores with metal up to the surface of the anodized layer by AC deposition or modified AC deposition; depositing a pore-filling metal into the pores so as to continue depositing the pore-filling metal to form a continuous support layer having a thickness in the range of about 0.5 to 3 microns on the surface of the anodized layer; . forming at least one finish metal coating on the support layer. 2. The method of claim 1, wherein the anodizable metal is selected from the group consisting of aluminum and anodizable aluminum alloys. 3. A method according to claim 1 or 2, characterized in that the pore-filling metal is selected from the group consisting of nickel, cobalt, copper, tin and mixtures thereof. (4) The method according to any one of claims 1 to 3, wherein the finishing metal is chromium. 5. The method of claim 4, wherein the layer of chrome-finished metal has a thickness of about 1 to 5 microns. (6) A method according to any one of claims 1 to 3, characterized in that the finishing metal is electrolessly plated onto the support layer. 7. The method of claim 1, wherein the finish metal is electrolessly plated onto the support layer to a thickness of about 10 to 25 microns. 8. The method of claim 1, wherein the finishing metal is nickel electrolessly plated onto the support layer to a thickness of about 10 to 25 microns. (9) The substrate is first surface anodized to form a large pore anodized layer portion with large pores opening into the free surface, and then between the large pore layer portion and the remainder of the substrate. 9. A method according to any one of claims 1 to 8, characterized in that the anodization is performed to form a small pore anodized layer section having small pores communicating with large pores of the large pore layer section. (10) The first anodization that forms large pores is acid anodization using phosphoric acid, and the subsequent anodization that forms small pores is selected from the group consisting of sulfuric acid, chromic acid, oxalic acid, and mixtures thereof. 10. The method according to claim 9, characterized in that it is acid anodization using an acid. (11) The substrate is first anodized with phosphoric acid to form a large-pore anodized layer portion and then anodized with sulfuric acid to form a small-pore anodized layer portion.
The method described in. (12) The base body has a lateral dimension of approximately 0.07 to 0.07 mm.
Anodized to form a large pore anodized layer section with pores as large as 1 micron, then approximately 0.01 to 0.0
10. A method according to claim 9, characterized in that it is anodized to form a small hole anodized layer section with a corresponding lateral dimension of 2 microns. (13) The substrate is first anodized to form a large pore anodized layer portion having large pores with a lateral dimension of about 0.09 microns, and then a corresponding lateral dimension of about 0.015 microns. 10. The method of claim 9, wherein the method is anodized to form a small hole anodized layer portion. (14) The substrate is first anodized with phosphoric acid while increasing the anodizing voltage from the value for sulfuric acid anodization to the maximum value for phosphoric acid anodization and then decreased to said value for sulfuric acid anodization; 14. A method according to any one of claims 9 to 13, characterized in that the sulfuric acid anodization is carried out while maintaining the anodic treatment value. (15) In a method of depositing a finishing metal layer on the surface of a substrate made of an anodizable metal, the surface of the substrate is first formed with a portion of a large-hole anodized layer having large holes opening to the free surface. and then anodizing to form a small pore anodized layer portion between the large pore layer portion and the remainder of the substrate having small pores communicating with the large pores of the large pore layer portion. a step of anodizing the surface of the substrate to form a porous anodized layer; depositing a pore-filling metal on the porous anodizing layer to fill the pores; and supporting the pore-filling metal thereon. 1. A method of applying a finish metal layer to a surface of an anodizable metal substrate, the method comprising the steps of: forming a layer; and forming at least one finish metal layer on a support layer. (16) The first anodization that forms large pores is acid anodization using phosphoric acid, and the subsequent anodization that forms small pores is selected from the group consisting of sulfuric acid, chromic acid, oxalic acid, and mixtures thereof. 16. The method according to claim 15, characterized in that it is acid anodization using an acid. (17) The substrate is first anodized with phosphoric acid to form a large-pore anodized layer portion and then anodized with sulfuric acid to form a small-pore anodized layer portion.
The method described in 5. (18) The base body has a lateral dimension of approximately 0.07 to 0.07 mm.
Anodized to form a large pore anodized layer section with pores as large as 1 micron, then approximately 0.01 to 0.0
16. A method according to claim 15, characterized in that it is anodized to form a small hole anodized layer section with a corresponding lateral dimension of 2 microns. (19) The substrate is first anodized to form a large pore anodized layer portion having large pores with a lateral dimension of about 0.09 microns, and then a corresponding lateral dimension of about 0.015 microns. Claim 1 characterized in that the anodized layer is anodized to form a small pore anodized layer portion having small pores.
The method described in 5. (20) The substrate is first anodized with phosphoric acid while increasing the anodizing voltage from the value for sulfuric acid anodization to the maximum value for phosphoric acid anodization and then decreased to the said value for sulfuric acid anodization; Claims 15 to 19 characterized in that the sulfuric acid anodization is performed while maintaining the value of anodization.
The method described in any of the above. 21. The method of claim 15, wherein the anodized layer has a thickness of about 1 to 10 microns. 22. The method of claim 15, wherein the support layer has a thickness of about 0.5 to 3 microns. 23. The method of claim 15, wherein the finishing layer has a thickness of about 1 to 5 microns. (24) A method according to any of claims 15 to 23, characterized in that the finishing metal is electrolessly plated onto the support layer. (25) Claim 1, wherein the finishing metal is electrolessly plated onto the support layer to a thickness of about 10 to 25 microns.
24. The method according to any one of 5 to 23. 26. The method of claim 15, wherein the finishing metal is nickel electrolessly plated onto the support layer to a thickness of about 10 to 25 microns. (27) The hole-filling metal is deposited by a DC-superimposed AC deposition method so as to completely fill the holes and form a support layer. the method of.