JPH0277585A - Palladium/nickel alloy layer as intermediate between metal base material having no or almost no corrosion resistance - Google Patents

Abstract

PURPOSE: To improve the corrosion resistance and mechanical adhesive power of a film formed by a PVD method, by depositing a Pd/Ni alloy layer under specified conditions as an intermediate layer between a metallic base material having no corrosion resistance and this film.

CONSTITUTION: The Pd/Ni alloy layer is deposited as the intermediate layer on the metallic base material having no corrosion resistance or having substantially no corrosion resistance at the time of applying the film by the PVD method on the base material. The intermediate layer is deposited from an aq. electrolyte consisting of palladium amine and nickel amine contg. 2 to 20g/l Pd and 5 to 30g/l Ni adjusted in the Pd/Ni ratio to the extent of contg. 30 to 90% Pd and, in some cases, org. additives having a conductive salt and sulfur. The electrolyte components are so selected that the sulfur has bivalent or higher valence when the sulfur is deposited. The defect of the film to be formed is prevented by the formation of such intermediate layer.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the application of coatings produced by the PVD method to metal substrates.

PRIOR ART In the above-mentioned cases, industrial as well as decorative coatings are important. PVD stands for physical vapor deposition (physical vapor deposition).
vapor deposition).

In this case, the commonly used coating materials are metal borides, metal carbides, metals of the elements titanium, zirconium, hafnium or vanadium, niobium, tantalum or chromium, molybdenum, tungsten from subgroups 4 to 6 of the periodic table. It is a single substance or a combination of nitrides, metal oxides, and metal silicides. Of particular importance in this case are carbides, nitrides and oxides of elements of the fourth subgroup of the periodic table. This is because coating materials such as TiN (gold-colored) or TiC (charcoal-free), which can outperform hard chrome coatings by several times, apart from their high hardness and wear resistance, are This is because attractive decorative shades can also be achieved. Such coating materials may contain corresponding admixtures of other elements such as aluminium, cobalt, gold, carbon, copper, nickel, palladium and thus have a blue, brown, green, red or silver color. Decorative shades can also be obtained. Furthermore, metallic materials such as aluminium, titanium, zirconium, platinum or gold can also be deposited using the PVD method, so that layer combinations can also be obtained in corresponding equipment with multiple sputter sources. Titanium can, for example, be surface oxidized chemically or electrochemically after the fact, so the tint can be achieved in all ways of the spectrum. However, it is also possible, for example, to deposit amorphous and/or aphrite-like carbon by means of a PVD method in order to obtain a particularly abrasive and abrasive surface.

The PVD method has been found to be effective in many areas of industry (UK Patent No. 2,123,039) and is suitable for the substrate itself when the coated object is required to be corrosion resistant. The premise that the coating is sufficiently corrosion resistant leads to a remarkable improvement in the quality of the coated product. This applies, for example, to austenitic chromium/nickel steel or titanium itself as a substrate in the case of coatings applied by the PVD method, such as titanium carbide or titanium nitride. However, if the substrate is non-corrosion resistant or hardly corrosion resistant, depending on the respective corrosion resistance conditions, it may mimic corrosion phenomena later in actual use (for example, aluminum, lead, copper ,magnesium,
Nickel, silver, steel, zinc or numerous alloy materials based on these, such as brass, bronze, German silver, Monel metal,
This applies to metal substrates such as Alvaca, zinc sheet casting alloys, lead centrifugal casting alloys, etc. Corrosion phenomena can be caused by matte, dull, or currentless deposits on such substrates, either by additional plating or by currentless deposition.
The same thing happens if a bright, semi-gloss or dull gloss lower layer is provided as a chromium layer, a copper layer, a copper alloy layer, a nickel layer, a nickel alloy layer, a silver layer or a tin alloy layer or a layer system thereof. . The same is usually applied with currentless metallization followed by currentless deposited paulownia or nickel phosphorus or nickel boron with a bright copper layer and a bright or dull nickel layer and possibly a bright chrome coating. e.g. ABS (acrylonitrile-butadiene-styrene) or polycarbonate/
Copolymers from ABS (e.g. Bayb
This also applies to plated plastics such as Lend - Bayer, Leverkusen, polypropylene, etc.

Corrosion phenomena may occur because coatings applied by the PVD method are often porous or have microcracks within the customary layer thickness range of 0.3 to 1 μm, especially under low coating temperatures and non-pure air conditions. It is based on its ability to have pinhole density and extremely rich electrochemical possibilities. The reason for the high pinhole density is that the coating produced by the PVD method advantageously grows in the form of a rod perpendicular to the substrate surface, which at the same time has a sufficient thickness in terms of thickness. There is no growth and thus no closed homogeneous surface. Defects in this layer can indeed be reduced as the layer thickness grows, but such a method would already be too expensive in terms of equipment technology solely due to the very slow deposition rate of the PVD method. . Furthermore,
In many cases, especially plated plastics,
Extremely low PVD in the range of 100-120°C to ensure that the Vicat softening temperature of the plastic is not achieved
Only processing temperatures should be used. Despite that,
At such extremely low processing temperatures, it is often not possible to deposit a complete layer per se by the PVD method.

Disturbing corrosion phenomena can be considered to be adversely affected by an intermediate layer consisting of a very precious metal such as gold or platinum, which of course cannot be chromium-plated with at least an adhesive strength in the conventional plating process. It will not be possible to deposit on the surface. This is expensive on the one hand and on the other hand the intermediate layer, such as gold in particular, is very soft, which is very easy to do in the later stages of applying the coating by the PVD method. May cause damage. Furthermore, intermediate layers of low microhardness are often particularly disadvantageous below hard material covering layers. Additionally, testing has shown that interlayers such as gold cause adhesion problems when the PVD applied coating is mechanically subjected to shear stress.

OBJECTS TO BE SOLVED BY THE INVENTION Accordingly, an object of the present invention is to improve the corrosion resistance and mechanical properties of PVD coatings in the case of assemblies consisting of non-corrosion-resistant or hardly corrosion-resistant substrates and coatings applied by the PVD method. The objective is to improve the adhesion of the target.

Means for Solving the Problem The problem is achieved by adjusting the palladium/nickel ratio to such an extent that the alloy deposited by plating has a palladium content of 30 to 90% by weight within the range of 2 to 20 v/Q. palladium/nickel amine with a palladium content in the range from 5 to 30 g/12 and an aqueous electrolyte consisting of a nickel amine and optionally conductive salts and organic additives which may have sulfur. A nickel alloy layer is used as an intermediate layer between a non-corrosion-resistant or barely corrosion-resistant metal substrate and a coating applied by a PVD method, in which case the electrolyte components are co-deposited with sulfur. This is achieved in that the sulfur is selected to have a valence higher than divalence.

The electrolyte contains additives of aliphatic sulfonates, unsaturated sulfonates and/or heterocyclic sulfonates and optionally aromatic sulfonimides as tensile stress reducers or anti-corrosion additives and also non-ionogenic wetting agents. conductive salts selected from agents and/or anionically active wetting agents, and indeed in this case aliphatic sulfonates, unsaturated sulfonates and/or heterocyclic sulfonates. Additives include vinyl sulfonic acid,
Allylsulfonic acid, propionesulfonic acid, methallylsulfonic acid, N-benzylpyridinium-2-ethyl-sulfonic acid, N-pyridiniumpropylsulfobetaine,
It consists of N-pyridinium methylsulfobetaine or the alkali metal salts (especially the sodium salts) of a number of these substances.

The metal substrate is aluminum, lead, copper, magnesium, nickel, silver, steel, zinc or alloy materials based on these, such as brass, bronze, German silver, Monel metal, Alba, zinc plate casting alloy or lead centrifugal casting alloy. For example, these are commonly used in industrial practice. Depending on the substrate or the desired optical effect or industrial conditions, these materials can be coated with additional plating or currentless copper, copper alloy, nickel, nickel alloy, silver or tin alloy layers. These layer systems may also have a lower layer with a matte, glossy, semi-gloss or dull gloss appearance. The definition of nickel layer and nickel alloy layer should also encompass dispersion nickel coatings and N1-P or N1-B coatings. Also,
In the case of metal substrates, surface layers applied by plating on plateable plasti-vine components, in particular matte, bright, semi-bright or dull copper layers, copper alloy layers, nickel layers, A nickel alloy layer, a silver layer or a tin alloy layer, alone or in a layer combination, is of interest. It is self-evident that palladium/nickel alloys cannot be deposited with adhesion strength by conventional plating methods, at least on a chromium plating bottom layer.

Surprisingly, the palladium/nickel alloy layer constructed and produced in accordance with the method according to the invention does not suffer from any damage, and in fact this intermediate layer is applied very thinly. will not be damaged even if The much higher microhardness of the palladium/nickel layer resists damage expected during subsequent PVD coating methods better than in the case of a nearly comparable pure gold interlayer. Even in the case of substrates which normally exhibit significant corrosion problems during use, this problem disappears when implementing the method according to the invention. The palladium/nickel alloy layer used in a special manner according to the invention is known per se (DE 31 08 508 and DE 3 232 735). Also, if the coating applied by the PVD method is mechanically subjected to shear stress, the question of number of necks no longer arises.

According to advantageous features, the object of the invention is characterized in that:
P on a metal substrate that is not or barely corrosion resistant
This is a method of applying a VD coating, in which case the palladium content within the range of 2 to 209/Q,
Palladium amines and nickel amines with a nickel content in the range from 5 to 309/Q, and additives of aliphatic, unsaturated and/or heterocyclic sulfonates and optionally tensile stress reduction A conductive salt selected from aromatic sulfonimides (benzoic acid sulfonimide or penzole sulfonylurea) as agents or anti-corrosion additives and furthermore nonionic wetting agents and/or anionically active wetting agents, deposited by plating. intermediate consisting of a palladium/nickel alloy deposited from an aqueous electrolyte in which the palladium/nickel ratio is adjusted to such an extent that the alloy has a palladium content of 30 to 90% by weight, preferably 60 to 85% by weight; layer, the additives being aliphatic sulfonates, unsaturated sulfonates and/or heterocyclic sulfonates as alkali metal salts, such as especially vinylsulfonic acid, allylsulfonic acid, propionic sulfonates, etc. Sulfonic acid, methallylsulfonic acid, N-benzylpyridinium-
2-ethyl-sulfonic acid, N-pyridiniumpropylsulfobetaine, N-pyridiniummethylsulfobetaine or the sodium salts of a number of these substances.

Known coatings that can be applied by the PVD method have already been mentioned above. In the case of coatings applied by the PVD method within the scope of the present invention, metal borides, metal carbides, metal nitrides, metal oxides of elements in subgroups 4 to 6 of the periodic table, Metal silicides can be of interest alone or in combination. In particular, carbides of elements of subgroup 4 of the periodic table,
Nitrides and oxides, such as TjO or YiC, or mixtures of various substances are of interest, which may also contain mixtures of aluminium, cobalt, gold, carbon, copper, nickel, palladium. but,
The PVD coating may have metallic properties such as aluminum, titanium, zirconium, gold, platinum, etc. Moreover, the coating can be amorphous carbon and/or aphrite-related carbon.

Before applying the palladium/nickel interlayer depending on the type of substrate, e.g. to ensure perfect adhesion of the palladium/nickel layer or to achieve a particularly dull gloss surface effect or in the case of plastics. Achieving temperature exchange stability in the composite plastic coating by means of a copper lower layer as thick as possible, another lower layer to be applied by plating to improve the roughness of the substrate by a flattened layer. is self-evident.

For this purpose, dispersion nickel coatings, N1-P coatings or N1
-B coating is mentioned. Furthermore, it is self-evident that when using plated plastics, the material type should be adapted to the processing temperature of the PVD method in relation to the Vicat softening temperature. A palladium/nickel layer cannot be applied on a chromium-plated lower layer by conventional plating methods, at least because of insufficient adhesion.

According to the invention, for the production of a non-porous or at least substantially porous palladium/nickel interlayer, this interlayer, in terms of its layer thickness, can be applied to the substrate and/or to the lower layer deposited by plating on it. Compatible with layer roughness and 0.1μm
has a minimum thickness of The layer thickness can be adapted to the roughness of the substrate or of the underlying layer deposited thereon.

In other words, the palladium/nickel interlayer has to be deposited thicker and thicker the rougher the substrate. The average layer thickness is in the range from 0.5 to 5 μm. The coating applied by Ij V D method has 0,1
5 μm, in particular 0.3 to 1 μm. PVD? It is self-evident that the processing parameters of the membrane should be adjusted in such a way that the coating has as low a layer defect density as possible (porosity, microcracks and pinholes).

EXAMPLES The invention and the advantages obtained will now be explained in more detail by means of examples.

A thin brass sheet M s 58 is precleaned according to the known rules for plating, electrolytically degreased, pickled, copper plated in a copper cyanide electrolyte to a thickness of about 1 μm and then copper plated to a thickness of about 7 μm. Bright nickel plated, and about 0.3μ in chromium sulfate electrolyte
Bright chrome plated with m.

For the PVD coating, the sheet is then precleaned under the action of ultrasound in emulsifier-containing Freon (product TWD 602 from Du Pont) and subsequently coated by the PVD method to a thickness of approx. 1”i of 5μm
Post-clean in Freon (Preor+) TF and ultrasound before applying the N-layer. Therefore, I] Cleaning in the Freon product prior to VD coating is desirable in order to attempt to remove all contaminants and finger prints when securing the PVD coating to a special transport frame.

Subsequently, test sheets of this type were each subjected to a dew point corrosion test (Schvitzv) in an SO7-containing atmosphere for 72 hours.
asser-rechselklisa) S F W
2. Various corrosion tests are carried out such as OD I N 50018 or Acetic Acid-Salt Spray Test ESS DIN 50021. Severe pitting with approximately 2-3 holes/cm2 can be seen on the test sheet. Such a test sheet can be corroded and perforated in a regular manner in parts.

Example 2 On the test sheets described in Example 1, only the bright chrome coating is replaced (without changing the layer structure) by an interlayer of a palladium/nickel alloy according to the invention with a thickness of 1 to 1.5 μm.

Incidentally, the corrosion tests described, each lasting 72 hours, are satisfactory.

The palladium/nickel electrolyte according to the invention can have the following composition: Palladium as [Pd(N113)4]CI2
69, nickel as [N1(NH3)[i]SO+ 9 g, (NH+hSO4 tLT, cD conductive salt tooy, sodium allylsulfonate 2.59 optionally additionally: benzoic acid sulfonimide, Na salt 1 g or 2 g of penzol sulfonylurea, and as a wetting agent, nonylfe/-ruet beef sill) (23EO) 0.52
．． 1) F (NH4OH to adjust the value 8-8.5.

Water for bath of Iσ, electrolyte temperature 25-30℃, easy product transfer, cathode current density IA/dm2, exposure time 4-6
Anode: Platinized titanium or graphite.

Instead of non-ionogenic wetting agents it is also possible to use selected anionically active surfactants based on alkyl sulfonates and alkylaryl ether sulfonates, for example: H3C-(CH2)12/14-0-
(CH2-CH2-0-) n -CI 2-C412
-CH2-3O3K ly/Q However, n = 11
.

Since such wetting agents have no clouding point, electrolyte temperatures of, for example, 40-50° C. can now be used.

At the same time the gloss of the deposit is still improved.

Example 3 The base material according to Examples 1 and 2 was made of steel C45WN 1.0
Replaced by 503. Similar results, i.e. Pd/N
It turns out that the i-interlayer is necessary for corrosion protection reasons.

Example 4 Addition of 0 on a titanium nitride layer applied by PVD
．． Sputter 1 μm of 23et-gold/nickel. The corrosion susceptibility according to Example 1 is even further enhanced, with Example 2 using a Pd/Ni interlayer instead of a bright chrome coating.
According to this, no corrosion phenomenon occurs at all.

Example 5 Titanium nitride can be replaced by titanium carbide, titanium-aluminum-carbon nitride, or metallic titanium. Again similar corrosion differences between Examples 1 and 2 can be observed.

7X, @fjA+ 6 Bayblend T 45 M
The test plates from N were first plated with nickel using a conventional plating method without electric current, and the N1-P layer deposited without electric current was pre-strengthened by electrolysis in a Watts electrolyte and then in a sulfuric acid electrolyte. Bright copper plating is carried out in a thickness of 20 to 30 .mu.m, followed by nickel plating with a dull luster of 10 .mu.m. Directly on top of this dull shiny nickel layer? ! When the ff1 layer was applied by the PVD method, no corrosion resistance was obtained according to the test of Example 1. However, the corrosion resistance is immediately given again when the intermediate layer is made of palladium/nickel in Example 2.

Instead of the 0.3 μm thick glossy chrome film according to Example 1, a 0.1 μm thick pure gold film was applied by electrolysis from a commercially available electrolyte, and a coating layer was applied on top of it by the PVD method. Rub.

When the wear behavior was tested using the drum polishing method and a commercially available polishing body, leaving aside the fact that the corrosion resistance was poor, it was found that the hard material coating layer regularly moved downward from the entire intermediate layer. do. When using the radium/nickel interlayer according to the invention, the PVD coating layer is significantly adhered, ie the entire interlayer is extremely sensitive to shear stresses.

EXAMPLE 8 Aliphatic sulfonates, unsaturated sulfones, etc. can be used without special requirements for a significantly higher decorative gloss of the radium/nickel interlayer, especially for many industrial applications. Palladium/di-Tschel electrolytes can be used as well without acid salts and/or heterocyclic sulfonates and without aromatic sulfonimides. The radium/nickel interlayer also provides the necessary corrosion resistance and also provides the sulfur when it is co-deposited.
If it is ensured that the valence is higher than the valence, this also results in better adhesion of the subsequently applied PVD coating. Composition of electrolyte: Radium as [Pd(NH3)4]C12
6g, [N1(NH3)[i]SO4 or (H2N
Nickel as SO3)2Ni・4H20
10g, (NI+4)2SO4 or 82
Conductive salt as NS03NH4
50-100 g, optionally additionally as wetting agent: II 3 cm (c H2) 12/14-0-(CH
2-CH2-0-)n -CH2-CH2-CH2-3
O3K Iy However, n=11゜p N H4o H1 to adjust the H value 8 to 8,5
Water for bath of Iσ, electrolyte temperature 40-50℃, easy product transfer, cathode current density IA/dm2, exposure time 4-6
Anode: Platinized titanium or graphite.

Test run as in Example 2. The corrosion test described in Example 2 was constructed.

Agent: Patent Attorney 1) Osamu Kuro

Claims (1)

[Scope of Claims] 1. Palladium content in the range of 2 to 20 g/l, where the palladium/nickel ratio is adjusted to such an extent that the alloy deposited by plating has a palladium content of 30 to 90% by weight; A palladium/nickel alloy layer deposited from an aqueous electrolyte consisting of palladium and nickel amines with a nickel content in the range from 5 to 30 g/l and optionally conductive salts and organic additives which may have sulfur. , as an interlayer between a non-corrosion-resistant or poorly corrosion-resistant metal substrate and a coating applied by a PVD process, where the electrolyte component is such that the sulfur is present when the sulfur is co-deposited. Palladium/nickel alloy layer, characterized in that it is selected to have a valence higher than divalence. 2. The electrolyte contains additives of aliphatic sulfonates, unsaturated sulfonates and/or heterocyclic sulfonates and optionally aromatic sulfonimides as tensile stress reducers or anti-corrosion additives and also non-ionogens. conductive salts selected from wetting agents and/or anionically active wetting agents, with additives of aliphatic sulfonates, unsaturated sulfonates and/or heterocyclic sulfonates including vinyl sulfonic acid, allyl sulfonic acid, propionosulfonic acid, methallylsulfonic acid, N-benzylpyridinium-2-ethyl-sulfonic acid, N-pyridiniumpropylsulfobetaine, N-pyridiniummethylsulfobetaine or a number of the alkali metal salts of these substances, especially palladium according to claim 1, consisting of a sodium salt)
Nickel alloy layer. 3. Metal base material is aluminum, lead, copper, magnesium,
Nickel, silver, steel, zinc or alloy materials based on these materials, which can be coated with copper layers, copper alloy layers, nickel layers, nickel alloy layers, by additional plating or without electric current.
3. The palladium/nickel alloy layer as claimed in claim 1, which may be provided with a matte, glossy, semi-gloss or dull luster lower layer as a silver layer or a tin alloy layer or a layer system thereof. 4. In the case of metal substrates, surface layers applied by plating on plateable plastic components, in particular matte, bright, semi-bright or dull copper layers, copper alloy layers, nickel layers; Palladium/nickel alloy layer according to claim 1 or 2, in which a nickel alloy layer, a silver layer or a tin alloy layer is important alone or in a layer combination. 5. In the case of coatings applied by the PVD method, metal borides, metal carbides, metal nitrides, metal oxides, and metal silicides of elements in subgroups 4 to 6 of the periodic table are used. Palladium/nickel alloy layer according to any one of claims 1 to 4, in which the following substances are important alone or in combination. 6. Palladium/nickel alloy layer according to claim 5, wherein the coating applied by the PVD method may additionally contain corresponding mixtures of aluminum, cobalt, gold, carbon, copper, nickel, palladium. . 7. Claims 1 to 4, wherein the coating applied by the PVD method is made of metal aluminum, titanium, zirconium or tantalum, which may be surface oxidized afterwards chemically or electrochemically. The palladium/nickel alloy layer according to any one of the above. 8. Claim 1, wherein the coating applied by the PVD method is made of amorphous carbon and/or diamond-related carbon.
The palladium/nickel alloy layer according to any one of 4 to 4. 9. For the production of a nonporous or at least substantially porous palladium/nickel interlayer, which in terms of layer thickness is adapted to the roughness of the substrate and/or of the lower layer deposited on it by plating. Palladium/nickel alloy layer according to any one of claims 1 to 8, wherein the palladium/nickel alloy layer has a minimum thickness of 0.1 μm. 10. The average layer thickness of the palladium/nickel intermediate layer is 0.
Palladium/nickel alloy layer according to claim 9, which is in the range of 5 to 5 μm. 11. The film applied by PVD method has a thickness of 0.1 to 5 μm.
Palladium/nickel alloy layer according to any one of claims 1 to 10, having a thickness in the range of from 0.3 to 1 μm. 12, particularly in the case of industrially functional layer systems, palladium/
12. Palladium/nickel alloy layer according to claim 1, wherein a combination of a nickel intermediate layer and a PVD-applied coating layer replaces the hard chromium coating.