JPS5937756B2 - Plating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for plating soldered parts, and its features include copper, copper alloys and copper plating, or nickel, nickel alloys and electroless nickel plating on nickel plating. Plating is performed to a thickness of 5μ or more, and then glossy tin plating or glossy solder plating is applied to the required thickness.

Conventionally, soldered parts have been manufactured using bright tin plating, bright solder plating, silver plating directly on copper, copper alloys and copper plating, or nickel, nickel alloys and nickel plating.
He was doing gold plating.

Methods using silver plating or gold plating become expensive when the product is large, and cannot be used for general products and are limited to special uses. On the other hand, the method using gloss tin plating and gloss solder plating uses a soldering temperature range (180 to 250'
When O is used, an intermetallic compound is formed with copper or nickel metal, and the plating film tends to peel off.

This invention aims to improve the problems in the conventional plating method for soldered parts, and uses an electroless nickel plating film as a barrier film to prevent the formation of intermetallic compounds, thereby achieving a bright tin plating or glossy finish. This paper proposes a plating method that prevents peeling of the solder plating film. below,
The invention will be explained with reference to figures.

Figure 1 shows a cross section of the plated object, where 1 is the base material, 2
is a copper or nickel plating film, which is unnecessary if the base material 1 is copper, copper alloy, nickel, or nickel alloy.

3 is an electroless nickel layer, and 4 is a bright tin-plated or bright solder-plated layer.
This prevents n5, cu3sn, Ni3sn4, etc. from being generated in the soldering temperature range (180 to 250°C).

The above method is explained in an easy-to-understand manner in FIG. 2, which shows the plating process.

In Figure 2, the base material is prepared (A), copper or nickel plating is performed (B), and then electroless nickel plating of 5μ or more is performed (C), and then polished tin plate is applied. Performing soldering or bright soldering (D)O Next, examples will be shown regarding the adhesion test results of the plating film in the soldering temperature range according to the present invention.

Example I Aluminum alloy 5052 material was degreased with trichlor ethylene vapor at a temperature of 87 to 90°C for 60 to 90 seconds,
Bright tin plating was applied according to the conventional method shown below.

(C) Alkaline washing sodium hydroxide (10-20%wt%), temperature 40-
It was immersed for 10-20 seconds at 60°C.

(2) Wash in running water for 20-30 seconds (3) Pickling-I It was immersed in nitric acid (specific gravity 1.38) for 5 to 15 seconds at room temperature.

(4) Washing in running water for 20-30 seconds (5) Pickling mononitric acid (specific gravity 1.38) 3v01, hydrofluoric acid (50% VOl)
1v01, immersed for 10-20 seconds at room temperature (6) Rinse in running water for 20-30 seconds (7) Zinc-substituted sodium hydroxide 50 g/l, zinc oxide 5 g/1, Rothsiel salt 50 g/i) Ferric chloride 2 g/ Immerse in a solution of 50% VOl of nitric acid (specific gravity 1.38) for 40 to 60 seconds at room temperature (self) rinse with water for 20 to 30 seconds (9).
Immersion for 5 seconds AO) In rinsing water, 20-30 seconds aυ Same as zinc replacement (7), 20-30 seconds in AO washing water A3) Copper strike plating Cuprous cyanide 40g/l, Sodium cyanide 45g/l A current of 3 A/D77 l' was applied to a solution containing 12 g/l of sodium carbonate and 55 g/l of Rothsiel's salt at a temperature of 25 to 35°C.
Electricity was applied for 5 minutes to plate a metallic copper film with a thickness of about 1 μm.

A゜Water wash for 20-30 seconds Qω Copper plating copper sulfate 100g/l, sulfuric acid 200g/l, photoselector 10r
n1! A current of 2A/D7Fl' was applied to a solution of 2A/D7Fl' for 60 minutes at a temperature of 20 to 30C to plate a metal copper film with a thickness of 15μ.

Ae water washing aη 40 g/l of bright tinned stannous sulfate, 150 g/l of sulfuric acid, 30 m1/l of starter culmo (product of Matsukuzu Schrezter Co., Ltd., West Germany) at a temperature of 15 to 25°C with IA/Dm.
A current of 15 μm was applied for 60 minutes to plate a metal tin film with a thickness of 15 μm.

After plating the sample obtained by washing with water and processing for 20 to 30 seconds or more in running water, the above sample was baked at a temperature of 220°C for 30 minutes, although there was no abnormality in the 180° bending test until it broke. However, the plating film peeled off in the 180° bending test described above.

Example Steps (1) to (1e) of Example I above were carried out,
The following treatments were performed.

Afr) Nickel plating nickel sulfate 240g/l, nickel chloride 45g/l)
3A/l in a solution of boric acid 30g/l, saccharin 2g/1,1.4 butynediol 0.2g/l at a temperature of 40 to 60°C.
A current of D77l'' was applied for 30 minutes to plate a metal nickel film with a thickness of 10 μm.

Positive water washing Under running water for 20-30 seconds A9 glossy tin plating Same as step a'r) of Example I above.

After plating the thus obtained tamped sample in C2l water washing water for 20 to 30 seconds, the sample was baked at a temperature of 220°C for 30 minutes until it broke, although there was no abnormality in the 180° bending test.
In the above-mentioned 180° bending test, the plating film peeled off.

Example □ The steps of Example I above (from C to Qe) were carried out, and the following treatments were carried out.

Ar) Electroless nickel plating blue schema (manufactured by Nippon Kanigen Co., Ltd.) was immersed in a 5-fold diluted solution at a temperature of 90 to 95° C. for 15 minutes.

A ladder water washing Under running water for 20-30 seconds Q9) Glossy tin plating Same as step aη of Example I above.

(To) Rinse in running water for 20 to 30 seconds After plating the thus obtained sample and baking at 220℃ for 30 minutes, 180℃ until it breaks.
In the bending test at °, there was no peeling of the plating film and no abnormality.

Example copper plate was heated with trichlorethylene vapor at a temperature of 87 to 90.
Degreasing was carried out at 60 to 90 seconds at 0.degree. C., and gloss tin plating was applied according to the conventional method shown below.

(C) Alkali defatting sodium carbonate 70 g/l, sodium Ξ phosphate 15 g/l) Immersed at a temperature of 50 to 70°C for 10 minutes.

(2) Washing in running water for 20-30 seconds (3) Pickling sulfuric acid (specific gravity 1.84) 3v01, nitric acid (specific gravity 1.38)
1v01 mixture for 10 minutes at room temperature (4) Rinse with water for 20-30 seconds (5) Immerse in a solution containing 40 g/l of neutralized sodium cyanide for 10 seconds at room temperature (6) Rinse with water for 20-30 seconds Second (7) Copper strike plating Same as step A of Example I above.

(8) Washing with water Under running water for 20-30 seconds (9) Glossy tin plating Steps of Example I above aω washing with water Under running water for 20-30 seconds Same as aη.

After plating the plated sample thus obtained, there was no abnormality in the 180° bending test until it broke, but the sample was baked at a temperature of 220° for 30 minutes, and in the 180° bending test described above, the plated film did not show any abnormality. peeled off.

The following table shows experimental results when the above plating method was changed.

In this table, poor adhesion occurs at the boundary of intermetallic compounds, that is, Cu
It occurs between 6sn5 and Cu3sn.

As described above, by applying electroless nickel plating of 5μ or more between the copper or nickel plating film and the bright tin plating, diffusion between copper or nickel and tin can be prevented,
Furthermore, it is possible to prevent poor adhesion of the plating film within the soldering temperature range. Note that this plating method can also be applied to glossy solder plating.

According to this invention, it is possible to prevent poor adhesion of the plating film during soldering of bright tin or bright solder-plated soldered parts and to manufacture a product that can withstand impact after soldering. .

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the plating film according to the present invention, and FIG. 2 is a diagram showing the plating process of the present invention, where 1 is a base material, 2 is a copper or nickel plating layer, and 3 is an electroless nickel layer. , 4 are glossy tin or glossy solder plating layers.

Claims (1)

[Claims] 1 Copper, copper alloy, copper plating, or electroless nickel plating on nickel, nickel alloy, nickel plating of 5μ or more, and a gloss of the required thickness for the purpose of soldering on this electroless nickel plating layer. A plating method characterized by performing tin plating or glossy solder plating.