JPS5834554B2 - Golden watch case, band and network chain - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gold-colored watch case or band or neck chain.

The purpose of the present invention is to provide a watch case, band, or neck chain that is comparable in corrosion resistance, abrasion resistance, etc. to a gold-plated watch case, and whose cost is about 1/3 to 115 times lower than that of gold-plated watches. be.

Conventionally, gold-colored watch cases, bands, or neck chains have often been plated with gold or 18-23 Karat gold alloy to a thickness of 3-10μ.

In order to improve the corrosion resistance and abrasion resistance of the gold plating on the case and band, it is better to use thicker gold plating, but due to cost constraints, it has been done within the above range.

Due to the recent rise in gold prices, the cost of gold plating has increased,
The plating for one wristwatch case is 500 yen to 700 yen if the plating thickness is 5μ, and since the area of the band is large, the plating per watch case is 600 yen to 1,000 yen for a 3μ plating.
It cost about 00 yen.

However, it has been practically impossible to further reduce the thickness of the gold plating in order to reduce costs, as this would impair corrosion resistance, reduce abrasion resistance, and make the gold plating more likely to peel off.

For example, if the thickness of the gold plating is reduced to 7 lashes (less than 0.1μ) or around 1μ, the plating cost will be significantly lower, but
Thin plating like this is easily corroded by sweat, etc., and a patina can be removed from the base brass, deteriorating the appearance.

In addition, the base metal is exposed due to wear due to use, which corrodes and deteriorates the appearance, making it unsuitable for practical use.

In particular, neck chains for bands and pendants are prone to wear due to friction with the skin.

Therefore, thin plating is easy to peel off. The present invention seeks to overcome these obstacles and provide gold watch cases, bands, and neck chains that are low cost, corrosion resistant, and wear resistant.

That is, the present invention replaces only conventional gold or gold alloy plating,
A low-cost, corrosion-resistant golden copper-zinc-tin alloy plating is applied to the base, and gold or gold alloy plating is applied on top of this to create a low-cost, corrosion-resistant gold watch case, band, and neck chain. It is something.

Hereinafter, description will be made according to examples.

Example 1 Cupric cyanide CuCN Zinc cyanide Zn(CN)2 Sodium stannate Na25n03*an20 Free sodium cyanide NaCN Caustic soda Rochelle salt PH12,0 Bath temperature 50°C Current density 1-3A/drr+2 Under the above electrolytic conditions Brass watch case and pan 25g
/1 10g/1 75j! /11 20g/1 59/1 5(H!/1 5μ plating was applied to the chain and neck chain.

The appearance of this plating is close to gold.

Furthermore, 0.5 μm of gold plating was applied thereon.

In this plating solution, the composition of the precipitates changes depending on the electrolytic conditions, but for example, as the current density increases, the amount of copper deposited decreases.

Furthermore, as the amount of free sodium in the plating solution increased, the copper precipitation rate decreased, and as the amount of caustic soda increased, the copper deposition rate decreased.

Example 2 Copper cupric CuCN, 30g/l!
.

Back ratio Zinc Zn(CN)2 10 g/l Sodium stannate Na25n03-3H201009/l Free sodium cyanide NaCN 15 g/l Sodium carbonate Na2CO330g/l Sodium arsenite Na3 As03 19/
1PHIO~105 Temperature 55°C Current density 0.5~3 A/dm2 Addition of Na3As03 acts as a brightener
increase the precipitation of n.

The appearance of this plating was similar to that of 18 Karat gold alloy plating.

The watch case, band, and neck chain were plated with 5 microns of the above plating, and then gold-copper-cadmium 18 Karat ternary alloy plating was further applied as a final plating.

Example 3 Copper cupric CuCN 50g/l Zinc cyanide Zn(CN)2 10jj/12 Sodium stannate Na25n03-3H201009/1 Free potassium cyanide KCN 109/10 Tsusiel salt 459/l Caustic potassium KOH
59/1 Thiourea 1g/11PH1
0.5 to 12.0 Temperature: 60°C Current density: 1 to 5 A/drT12 A watch case, band, and neck chain were plated with 10 μm under the above conditions.

The exterior is bright gold.

23 Karat gold-nickel plating was applied thereon.

When the corrosion resistance was tested by varying the plating thickness using the plating solution with the above composition, the results shown in the following table were obtained.

(1) CAST Test The C'ASS test uses a liquid with the following composition, and the temperature is 3℃ for 24 hours.
Time went.

NaCl 5% cupric chloride o, 26.9/l acetic acid
0.1~0.3CC remaining
Water P H3,0 Table 1 CASS test results (24 hours) Table 3 Artificial sweat immersion results (3) Ammonia aeration test 2 on top of concentrated ammonia water Table 4 Table 4 Results of time exposure (4) Nitric acid aeration test The results of a sample plated on concentrated nitric acid are shown in Table 5 below.

Table 5: As a result of a corrosion resistance test lasting more than 2 hours, those that had been plated with a copper-zinc-tin tin ternary alloy plating of 5 microns and a final gold plating of 0.5 microns were easily comparable to those that had only gold plating of 3 microns or more applied. death,
Similarly, it was found that the corrosion resistance of the copper-zinc-tin tin ternary alloy plated with 5 μm or more and 1 μm final gold plating was comparable to that of the gold plated with 5 μm or more of gold plating, and it was found to be fully usable for practical use. .

Moreover, since the plating cost for these is 1/3 to 115 times that of gold plating alone, there is a great advantage in cost reduction.

However, since the color of the underlying copper-zinc-tin alloy plating is close to gold, there is no problem in terms of appearance even if some of the finishing gold plating is worn away, and the corrosion resistance of the underlying plating itself is also low. Because of this, it is also stronger than copper and brass, so there is almost no problem in practical use.

Therefore, the present invention has great practical benefits.

Claims (1)

[Claims] 1 Copper in a range that exhibits a color close to gold as a base plating.
A gold watch case, a band, and a neck chain, characterized in that they are coated with a zinc-tin ternary alloy plating of 5μ or more, and are further plated with gold or gold alloy plating of 0.5μ or more as a final plating.