JPS5928593A - Golden color plating method for rhodium - Google Patents

Abstract

PURPOSE:To obtain a golden color watch case having high hardness, high corrosion resistance and excellent chemical resistance, by applying alternating electrolysis to a decorative member having a silver color Rh surface in an aqueous sulfuric acid solution or an aqueous KOH solution respectively having a predetermined concn. to convert the Rh surface to a golden color. CONSTITUTION:The surface of a decorative member having plating (including sputtering and vacuum vapor deposition) applied thereto and an Rh surface such as a wristwatch case is changed to a golden color from a silver color. That is, this decorative member is especially immersed in 5-50% aqueous sulfuric acid or 50-300g/l KOH aqueous solution. In this state, alternating electrolysis of 1-1,000Hz (sufficient at 50 or 60Hz) is applied to said aqueous solution and the Rh surface is changed to a golden color by utilizing an electro-chromic phenomenon due to oxide film of Rh. The golden color rhodium product fabricated by this method can by widely used in a watch case, a band, a crown or a dial.

Description

[Detailed Description of the Invention] The present invention includes a rhodium surface obtained by plating (including sputtering, vacuum deposition, etc.). This relates to changing the color of the decorative part f3 of a watch case, etc., to gold.
5-50 sulfuric acid bath solution or 50-300 g/i
Immersed in KOH water bath solution -1 to 1 [100 Hz father flow [
14 (so or [6 UHz is sufficient), the rhodium table [III? It has the characteristic of changing the color to gold. Conventional gold plating methods include gold plating, thin plating, and titanium nitride using ion routing, but each of them has some drawbacks. S, gold plating is hard Vickers hard 111
00 to 200) have problems, and scratches, nicks, and thin spots can be treated as small materials due to poor corrosion resistance. Furthermore, since titanium nitride requires vacuum equipment, it is costly, and it is generally not possible to thicken it to a thickness of 17J or 1 or more (even if it is possible, it will be expensive. There are many dense layer defects), so it is not suitable for use as a base metal. The present invention 1-1, in which the corrosion resistance is not completely satisfied in the case of corrosion resistance and corrosion resistance. c) By eliminating such drawbacks, the present invention provides a Vickers rupture Hv 8
Rhodium metal has a value of 00 to 10 [ ] 0 and has excellent corrosion resistance and chemical resistance, and by making the surface gold, it shows a new gold color and can be used for watch cases, bands, lye cakes, etc. It became a practical ETt plating for paulownia wood.

The change in rhodium plating from silver to gold due to uninvention is 2 (lTf--'120.0H7O+20...
・・・・・・・・・・・・(117)0102 (
hydrogen ) +H20+ 2 e ” Rh2
03 fhydrouθ)+20H−・・・・・・(2
1 2Rho 2(hydr+)us l →Rh, 0.
3 f hydr, rous l→-V2O2-・-・t
A 3+ reaction can be considered.

That is, this is an electrochromic tga phenomenon of rhodium oxide, in which Rh(tVlffi compound is reduced to Rh(Iff) oxide by electrons obtained by Equation 11).

Dark conditions were used to cause the color to change to gold. In the case of a drunken bath - (lift concentration is preferably 5 to 50, preferably about 15 to 30%. If it is less than 5%, the BC phenomenon will not occur or it will be extremely slow. Also, if it is more than 50 It is not suitable for high-temperature use as it may cause rhodium peeling if high current is applied.

Further, in the case of K and OH, it is 30 to 300 y/l, preferably 50 to 100 f//l. A sword that does not cause KO phenomenon even if it is below 501//l or above 3110 Fl/1) It is extremely slow and impractical, 1! Solution method & J1-1000H2 exchange (50 father f16
0H2 is sufficient), 1 to 2 UV of tonden or 0.05
~10A tonryu hanike is used. In general, 11 comparisons and 1 low voltage rule are sufficient. (0.5~5V) The following will be explained with reference to examples. Example 1 A brass watch case (surface area 27 crA) was coated with Hi + Pd-Ni +Rk+ by a redundant method.
plating? The rice was immersed in a 20% sulfuric acid water bath solution, and a case was placed on both electrodes using a platinum jig. , AC 5 A/d
Electricity was applied for 5 minutes at m2, and when the case turned golden, it was taken out and dried after washing with water. Example Plated case k of Example 1, in which a gold plating with good properties (corrosion resistance, dense layering, etc.) was obtained when applied to a watch case.8. m Titanium platinum jig immersed in 1o% water bath solution? I used it to hang the case.

It was run for 10 minutes at AC 2 A/am, and the end point was when it turned golden, and JI2υ was calculated. etc.).

Example 3 Ni + Pct -Th1i-IR was applied to a watch case (surface area: 29C) made of Ni+Pct-Th1i-IR by the method described above.
It was plated, immersed in a 5011/l KOH water bath, and set in a case using a platinum jig for both electrodes. Electricity was applied at AC 2 A/cm for 5 minutes, and when the case turned gold, it was taken out, washed with water, and dried, resulting in a new gold plating. The mechanical properties such as corrosion resistance, layer density, and appearance were also sufficient.

EXAMPLE The plated case of Example 3 was immersed in 8011/l NFLOH water bath solution and hung using a thymine jig.

Electricity was applied at AC 2 A/ca for 3 minutes, and when a golden star was reached, the terminal point was taken out. Everything you need for 11 wrist cases!
It had excellent durability (corrosion resistance - multilayer properties, stability, etc.).

As explained above in Examples 1 to 4, as shown in Example 4, NaOH aqueous solution also contains 20 to 20 U.
///I tested the fruit by changing it to 1--same result as KOH? Obtained. , Also, regarding good resistance, it was soaked in artificial sweat for 48 hours,
I've finished the exam, and I've passed the exam.In terms of density, I got 11 out of 90 seats.

The golden cesium products created by this method are 11 for time g1,
It is possible to use a wide variety of things such as bands, crowns, letters, etc.

If this method is used, it will have high hardness, high surface resistance, and chemical resistance.

It meets the conditions required for watch case plating, such as adhesion, and can be easily applied with gold plating, so it can be used for applications other than watch case plating, and has industrial value. big.

that's all Applicant: Suwa Kozukosha Co., Ltd. Agent: Patent Attorney Mogami

Claims (1)

[Claims] Decorative parts with a rhodium surface are immersed in a sulfuric acid #5 to 50 water bath solution or a 30 to 500 g/JKOH water bath solution and subjected to AC electrolysis. A golden rhodium plating method characterized by 1ζ plating.