JPS5824516B2 - Composite plating method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a composite plating method.

More specifically, the present invention relates to a composite plating method in which a specific surfactant is added to a plating bath in composite plating using boron nitride as a composite material.

In the N1-BN composite plating method, in which boron nitride (hereinafter referred to as BN) is suspended in a nickel sulfamate bath and air is stirred, the specific gravity of BN is not much different from the specific gravity of the plating solution, and the surface tension of BN may be the cause. Therefore, BN is poorly compatible with the plating bath, and even if BN is added while air agitating the plating bath, some of the BN floats up together with air bubbles, forming a creamy layer on the surface of the plating solution.

Then, when putting the workpiece in and out of the plating bath, the BN
was adhered to the workpiece, significantly worsening workability.

The present invention aims to provide a composite plating method that does not have the above-mentioned drawbacks, and the method improves the dispersion of BN in the N1-BN composite plating bath by adding a specific amount of a specific surfactant to the N1-BN composite plating bath. However, it eliminates floating of BN on the plating liquid surface and foaming, improving workability, and does not have any adverse effect on the physical properties of the formed composite plating.

The surfactant used in the present invention is the sodium salt of formaldehyde condensate of β-naphthalene sulfonic acid (hereinafter referred to as N
(abbreviated as 5FNa), and its structural formula is shown below.

(Here, n represents an integer of 1 or more.) When this surfactant N5FNa is added to an N1-BN composite plating bath, it disperses BN well in the plating solution and causes foaming even when air agitation is performed. There is no adverse effect on the physical properties of the composite plating film.

In order for the surfactant N5FNa to have the above advantages and to have no effect on the internal stress of the plating solution due to the addition of the surfactant, the amount added should be 0 to the N1-BN composite plating bath. A suitable amount is .01 to 0.5% by weight.

There is no effect of addition below 0.01 wt%, 0.5 wt%
Even if you add more than that, the effect will not change.

The timing of injecting the N SF Na into the plating bath may be before, after, or simultaneously with the injection of BN into the plating solution, and the timing does not matter.

Example Nickel sulfamate bath 1 according to the conventional method! ! 20 to 25 g of BN was added to the plating bath, and the plating bath was air-stirred, but a part of the BN was not suspended in the plating bath, and a creamy foamed layer was formed on the bath surface.

Therefore, when the surfactant N5FNa was injected into the plating bath in an amount of 0% by weight, the foam layer on the bath surface disappeared after 5 minutes.
All of the BN became completely suspended.

Furthermore, since the above-mentioned N5FNa was used as a surfactant, the internal stress of the obtained plating layer was low, the adhesion was good, and no cracking or peeling occurred.

Here, we conducted a foaming comparison test on a composite plating bath in which 20 g of boron nitride and the surfactants shown in the table below were added at a ratio of 0.1 wt% to nickel sulfamate bath 11, and the following results were obtained. I got it.

As is clear from the above table, boron nitride (hereinafter abbreviated as BN).

) suspended in various plating baths, BSF
When surfactants other than Na are used, the height of the bubbles is extremely high, and these surfactants make plating work difficult.

Furthermore, it was investigated whether BN could be uniformly suspended in the plating bath when the surfactants shown in the above table were used.

After stirring the plating bath containing BN with a rotor,
When left standing, BN floats on the surface of the liquid when using surfactants other than BSFNa and FX-161.

Further, even after being left for a long period of time, BN is well maintained in a uniformly suspended state in the plating bath.

In the plated layer of N1-BN composite plating using BSFNa, the internal stress is close to zero and shows only a slight tensile stress.

This point differs from the fact that other anionic surfactants exhibit large internal stresses.

Therefore, since the internal stress is small, the plating film according to the present invention has the effect of not causing cracking or peeling.

Claims (1)

[Claims] 1. In composite plating in which boron nitride is suspended in a nickel sulfamate bath and air is stirred, 0.01 to 0.5% by weight of a formaldehyde condensate of β-naphthalene sulfonic acid is added to the composite plating bath. A composite plating method characterized by adding l-IJium salt.