JPH09125282A - Zincating agent onto aluminum and aluminum alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plating excellent in various plating appearances and adhesion by incorporating a specified reactant and its polymer by a specified amt. into the zincating bath for an aluminum alloy. SOLUTION: Zinc and zinc, iron, copper, cobalt or nickel are incorporated into a zincating bath for Al and an Al alloy. A reactant consisting of ammonia, aliphatic amine, polyamine, cyclic methylenepolyamine or amino alcohol, epichlorohydrin and dichlorohydrin and its polymer are incorporated by 0.001-50g/l into the bath. Consequently, a dense zincated film excellent in adhesion is formed.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a zinc (zinc alloy) displacement treatment bath as a pretreatment agent for plating on aluminum and aluminum alloys. More specifically, the present invention provides a zinc substitution treatment agent that has excellent adhesion, has the same performance as the conventional double zincate method in one substitution treatment, and has excellent plating appearance after zinc substitution. .

[0002]

2. Description of the Related Art For plating on Al and Al alloys, a predetermined plating has been conventionally performed after a zinc substitution treatment. This is because the natural oxide film exists on the Al surface, and thus the adhesion of the plating cannot be obtained as it is. Especially when adhesion is required, two-stage zinc substitution treatment called double zincate method is carried out. Once zinc substitution treatment is carried out, the film is stripped with nitric acid and then zinc substitution treatment is carried out again. By forming a zinc-substituted film, the adhesion of the plated film is enhanced. As the zinc substitution bath, zinc-iron system and zinc-copper system are selectively used depending on the type of post-plating and Al material, and cyan is used as the bath type.

The general zinc substitution bath composition and processing conditions are as follows. Non-cyan type zinc-iron system zinc oxide 10-40 g / l caustic soda 30-600 g / l Rochelle salt 20-30 g / l ferric chloride 3-15 g / l bath temperature 15 ° C-30 ° C treatment time 10 seconds-90 seconds nocyan Type Zinc-copper system Caustic soda 30-300 g / l Zinc oxide 10-30 g / l Rochelle salt 20-30 g / l Triethanolamine 3-15 g / l Ferric chloride 3-15 g / l Copper (II) sulfate 0-15 g / L Bath temperature 15 ° C to 30 ° C Treatment time 10 seconds to 90 seconds

At present, as a plating treatment method on Al,
Generally, the following steps are adopted. Degreasing → Etching → Smut removal → Zinc substitution (fast zincate) → Nitric acid film peeling → Zinc substitution (second zincate) → Various plating. → is washed with water In this way, the zinc substitution treatment is performed once after removing the coating with nitric acid, and then the zinc substitution treatment is performed again to increase the adhesion of the plating coating by generating a more dense zinc substitution coating, and at the same time, to improve the gloss of the plating. Is also improving. Therefore, it is very important and highly necessary to make the zinc substitution film dense by the double zincate method.

[0005]

However, the double zincate method has its limits, and stronger adhesion and excellent plating appearance (high gloss) are required.
Further, double zincate is wasteful in terms of resources because the film once subjected to displacement plating is dissolved and peeled off using nitric acid, and a large amount of cost is required for the waste liquid treatment, and the number of steps is still large, resulting in poor efficiency.

[0006]

The present inventor has conducted extensive studies in view of the problems of the conventional techniques as described above. As a result, the zinc (zinc alloy) substitution film produced by adding the following compounds in the following zinc substitution baths for general Al and Al alloys is more dense and has excellent adhesion. It has been found that this is excellent in various plating appearances after zinc substitution. If the compounding amount of each compound is 0.001 g / l or less, the effect is not remarkable and 10
If it is 0 g / l or more, a problem with adhesion tends to occur, so 0.01 to 50 g / l is preferable. Further, the strength of the adhesive force in the present invention is as strong as the double zincate of the conventional bath in the single treatment, and the conventional double zincate is not necessary and plating can be performed in the single treatment, which can solve the above problems. I found a thing. Further, it was also found that when the double zincate treatment was carried out in this invention bath, the maximum adhesion strength was increased as compared with the conventional one, and the present invention was completed here.

Ammonia, aliphatic amines, polyamines,
A zinc displacement treatment bath for aluminum and aluminum alloys, containing 0.001 to 50 g / l of a reaction product consisting of a cyclic methylene polyamine or amino alcohol and epichlorohydrin or dichlorohydrin and a polymer thereof.

Ammonia, aliphatic amines, polyamines,
A reaction product and a polymer thereof comprising cyclic methylene polyamine or amino alcohol and epichlorohydrin or dichlorohydrin, and further a halogenated alkyl compound,
It contains 0.001 to 50 g / l of a quaternary ammonium salt compound obtained by reacting an alkyl sulfate compound, monochloroacetic acid and its derivative, benzyl halide, and quaternary agent selected from sultone. A zinc substitution treatment agent for aluminum and aluminum alloys, which is characterized in that:

Polyethyleneimine alone or a compound obtained by quaternizing the nitrogen of polyalkyleneimine is added to 0.001-2.
A zinc substitution treatment agent for aluminum and aluminum alloys, characterized by containing 0 g / l.

A zinc substitution treating agent for aluminum and aluminum alloys, which contains 0.001 to 50 g / l of an aromatic aldehyde or a pyridine quaternary compound.

0.001 to 50 g of a compound obtained by quaternizing the internal nitrogen of imidazole and triazole compounds
A zinc substitution treatment agent for aluminum and aluminum alloys, which contains 1

A zinc substitution treatment agent for aluminum and aluminum alloys, characterized by containing 0.001 to 50 g / l of a reaction product comprising an imidazole or triazole compound and epichlorohydrin or dichlorohydrin and a polymer thereof.

0.001 to 20 g / of a quaternized polymerization condensate of an alkylene-based polyamine and a dihalopropanol
A zinc substitution treatment agent for aluminum and aluminum alloys, which contains 1

A reaction product comprising a nitrogen-quaternized compound of polyalkyleneimine, ammonia or an aliphatic amine or polyamine, a cyclic methylene polyamine or a compound of nitrogen atom of an aminoalcohol, and epichlorohydrin or dichlorohydrin, and its reaction product. A zinc substitution treatment agent for aluminum and aluminum alloys, containing 0.001 to 50 g / l of the coalescence.

[0015]

The present invention will be described in more detail with reference to the following examples.

Example: A zinc (zinc alloy) displacement bath having the following composition was prepared.

Bath of the present invention l Caustic soda 200 g / l Zinc oxide 20 g / l Rochelle salt 20 g / l Ferric chloride 10 g / l Ethylenediamine and epichlorohydrin reaction condensate 0.03 g / l

Inventive bath 2 Caustic soda 200 g / l Zinc oxide 30 g / l Rochelle salt 30 g / l Triethanolamine 15 g / l Copper (II) sulfate 15 g / l Ferric chloride 5 g / l Reaction condensate of ethylenediamine and epichlorohydrin 0 Compound obtained by quaternizing 10 g / l with methyl bromide

Inventive bath 3 caustic soda 150 g / l zinc oxide 18 g / l sodium gluconate 25 g / l ferric chloride 8 g / l EDTA 3 g / l polyethyleneimine 0.05 g / l

Inventive bath 4 caustic soda 150 g / l zinc oxide 18 g / l sodium gluconate 25 g / l ferric nitrate 10 g / l vanillin 3 g / l

Inventive bath 5 Caustic soda 120 g / l Zinc sulfate 20 g / l Sodium gluconate 25 g / l Ferric sulfate 8 g / l Vinylpyridine quaternary product 0.01 g / l

Bath 6 of the invention Caustic soda 250 g / l Zinc oxide 25 g / l Sodium gluconate 30 g / l Cobalt sulfate 10 g / l Imidazole quaternary product 0.08 g / l

Inventive bath 7 Caustic soda 250 g / l Zinc oxide 25 g / l Sodium gluconate 30 g / l Ferric sulfate 10 g / l Imidazole quaternary compound 0.04 g / l Reaction product of epichlorohydrin

Inventive bath 8 Caustic soda 250 g / l Zinc sulfate 25 g / l Sodium gluconate 30 g / l Cobalt sulfate 10 g / l Hexamine and dichloropropanol quaternized polymerization condensate 0.20 g / l

Inventive bath 9 Caustic soda 150 g / l Zinc oxide 20 g / l Citric acid 30 g / l Triethanolamine 15 g / l Copper (II) sulfate 7 g / l Cobalt sulfate 2 g / l Polyerylene imine quaternized product and epichlorohydrin Reaction product 1g / l

Bath of the present invention 10 Zinc sulfate 30 g / l Hydrofluoric acid 10 g / l Nickel sulfate 30 g / l Reaction product of polyethyleneimine quaternary product and epichlorohydrin 5 g / l

Comparative Example 1 Caustic soda 500 g / l Zinc oxide 40 g / l Rochelle salt 25 g / l Ferric chloride 8 g / l

Comparative Example 2 Caustic soda 150 g / l Zinc oxide 18 g / l Sodium gluconate 25 g / l Sodium cyanide 10 g / l Ferric chloride 8 g / l

Comparative Example 3 Caustic soda 150 g / l Zinc oxide 20 g / l Citric acid 30 g / l Triethanolamine 15 g / l Copper (II) sulphate 7 g / l Cobalt sulphate 2 g / l

Comparative Example 4 Zinc sulfate 30 g / l Hydrofluoric acid 10 g / l Nickel sulfate 30 g / l

Treatment step 1 (single zincate process) Using JIS A6063 material as an aluminum material in accordance with a conventional method, after degreasing → alkali etching → desmutting nitric acid, dipping in each of the above zincate solutions for 30 seconds (20 ° C.), water washing latter half gloss electric Nickel plating was applied to 2 to 50 μm.

Treatment Step 2 (Double Zincate Process) Using JIS A6063 material as an aluminum material in accordance with a conventional method, after degreasing → alkali etching → desmutting nitric acid, dipping in each of the above zincate solutions for 30 seconds (20 ° C.) and then nitric acid dipping. After the coating was peeled off, the sample was again immersed in each of the zincate solutions for 30 seconds (20 ° C.), and then semi-bright electrical nickel plating was applied for 2 to 50 μm.

The adhesion was judged by using a peeling test of 1 cm width for the presence or absence of peeling of the plating film due to bending and the strength. (Plating film thickness 50 μm) Regarding the plating appearance, the glossiness of the electroless nickel plating film thickness 2 μm was visually compared. The results are shown in Table 1 below.

[0034]

[Table 1] The test evaluation results are indicated by the following symbols.

[0035]

As is clear from the above results, when the zinc substitution bath of the present invention is used, it is possible to perform plating treatment on Al having very strong adhesion and excellent plating appearance, and it is necessary to use conventional double zincate. However, the single zincate treatment is also possible. This is because the solution of the present invention is accompanied by fine particles of zinc displacement plating, and thus it is possible to form a more precise zinc displacement film having excellent adhesion, and as a result, plating excellent in adhesion and excellent in various plating appearances. Processing is possible.

Claims (8)

[Claims] 1. As a pretreatment for plating aluminum and aluminum alloys, a zinc substitution bath for Al and Al alloys containing zinc and zinc, iron, copper, cobalt or nickel, ammonia, aliphatic amine, polyamine, A zinc substitution treatment agent for aluminum and aluminum alloys, containing 0.001 to 50 g / l of a reaction product consisting of cyclic methylene polyamine or amino alcohol and epichlorohydrin or dichlorohydrin, and a polymer thereof. 2. As a pretreatment for plating aluminum and aluminum alloys, ammonia, an aliphatic amine, a polyamine, and a zinc substitution bath for Al and Al alloys containing zinc and zinc, iron, copper, cobalt or nickel. A reaction product of a cyclic methylene polyamine or amino alcohol and epichlorohydrin or dichlorohydrin and a polymer thereof, and any one selected from halogenated alkyl compounds, alkyl sulfate ester compounds, monochloroacetic acid and its derivatives, benzyl halides and sultones. A zinc substitution treatment agent for aluminum and aluminum alloys, containing 0.001 to 50 g / l of a quaternary ammonium salt compound obtained by reacting a quaternizing agent. 3. As a pretreatment for plating aluminum and aluminum alloys, a zinc substitution bath for Al and Al alloys containing zinc and zinc, iron, copper, cobalt, or nickel is added with polyethyleneimine alone or polyalkyleneimine. 0.001 to quaternary nitrogen compounds
A zinc substitution treatment agent for aluminum and aluminum alloys, which contains 20 g / l. 4. As a pretreatment for plating aluminum and aluminum alloys, aromatic aldehyde or pyridine quaternization is applied to a zinc substitution bath for Al and Al alloys containing zinc and zinc, iron, copper, cobalt or nickel. A zinc substitution treatment agent for aluminum and aluminum alloys, which comprises 0.001 to 50 g / l of a compound. 5. As a pretreatment for plating aluminum and aluminum alloy, zinc substitution bath for Al and Al alloy containing zinc and zinc, iron, copper, cobalt or nickel, and intramolecular nitrogen of imidazole and triazole compounds. 0.001 to 50 g of a quaternized compound
A zinc substitution treatment agent for aluminum and aluminum alloys, characterized by containing 1 / l. 6. As a pretreatment for plating aluminum and aluminum alloys, alkylene-based polyamines and dihalopropanol are added to a zinc substitution bath for Al and Al alloys containing zinc and zinc, iron, copper, cobalt or nickel. 0.001-20g of quaternized polymerization condensate with
A zinc substitution treatment bath for aluminum and aluminum alloys, characterized in that 7. As a pretreatment for plating aluminum and aluminum alloys, a zinc substitution bath for Al and Al alloys containing zinc and zinc, iron, copper, cobalt or nickel is prepared from imidazole and triazole compounds and epichlorohydrin or dichlorohydrin. A zinc substitution treatment agent for aluminum and aluminum alloys, containing 0.001 to 50 g / l of the reaction product and its polymer. 8. As a pretreatment for plating aluminum and aluminum alloys, nitrogen of polyalkyleneimine is quaternary in a zinc substitution bath for Al and Al alloys containing zinc and zinc, iron, copper, cobalt or nickel. Containing a compound and an ammonia or an aliphatic amine or a polyamine or a cyclic methylene polyamine or a compound of a quaternary nitrogen atom of an aminoalcohol, and epichlorohydrin or dichlorohydrin, and a polymer thereof in an amount of 0.001 to 50 g / l A zinc displacement treatment bath for aluminum and aluminum alloys.