JPS6152389A - Method for carrying out direct bright plating of titanium or titanium alloy with noble metal - Google Patents

Abstract

PURPOSE:To carry out the direct bright plating of a Ti or Ti alloy material with a noble metal by heat treating the material under oxidation, treating it with a treating soln. contg. a reducing agent and soluble Ti salt as principal components, and plating the treated material. CONSTITUTION:A Ti or Ti alloy material is heat treated at 100-600 deg.C for >=about 5min in the air or an oxidizing atmosphere. The surface of the heat treated material is degreased, washed, and activated with a treating soln. of <=10.0pH contg. a water soluble reducing agent and a soluble Ti salt as principal components by immersion or electrolysis. The activated material is directly plated with a noble metal to form lustrous and fine noble metallic plating having high adhesion and maintaining its appearance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to decorative products such as metal eyeglass frames, pendants, watch cases, and bands made of titanium or titanium alloy. This relates to a method of directly applying precious metal plating.

[Conventional technology]

Titanium or titanium alloy itself is a material that is lightweight and has excellent corrosion resistance, but when precious metal plating is applied to titanium or titanium alloy material, not only the appearance is damaged but also the adhesion of the precious metal plating is incomplete. .

Therefore, in the past, instead of directly applying cladding materials to titanium or titanium alloy materials, cladding materials of metals that can be plated, such as nickel or copper, were manufactured on titanium-nickel cladding materials and titanium-copper cladding materials (hereinafter referred to as titanium-copper cladding materials). Products were processed using titanium-clad material (known as titanium-clad material) and plated with precious metals.

[Problem to be solved by the invention 0 As mentioned above, when titanium or titanium alloy materials are directly plated with precious metals, the appearance is impaired and the adhesion of the precious metal plating is incomplete. It has not been possible to apply precious metal plating, which has a specular luster, an elegant appearance, and perfect adhesion and is rich in practicality, onto the material.

In addition, when titanium clad material is used as a material, extremely high processing costs are required to manufacture the titanium clad material itself, and in addition, the raw material of titanium or titanium alloy is required at the processing stage to prepare the manufacturing mold. There was also a problem in that the nickel and copper covered in the material would disappear locally due to wear and other factors.

The object of the present invention is to provide an elegant noble metal plating method that does not impair the appearance of titanium or titanium alloy materials even when the material is directly plated with noble metals and has a glossy appearance.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention provides a first treatment for products made of titanium or titanium alloy.
Heat treatment is performed for 5 minutes or more in the air or in an oxidizing atmosphere at a temperature of 00°C.

Next, as a second treatment, the surface of the heat-treated material is degreased and cleaned, and activated by immersion or electrolysis in a treatment solution containing a water-soluble reducing agent and a soluble salt of titanium as the main components. Next, the activated material was plated with precious metals.

〔Example〕

The first to fourth embodiments of this invention will be described below with reference to FIGS. 1 and 2.

Figure 1 is a diagram showing the state of adhesion of the plating layer in the outside air and temperature changes, and Figure 2 is a chart showing the state of adhesion of the plating layer in the presence or absence of and changes in the content of water-soluble reducing agent and soluble titanium salt. be.

The first example is a titanium alloy plate (first type, 50×100
×1.01all) is subjected to a heat treatment for 10 minutes in the atmosphere at a temperature of 200° C. as a first treatment.

Next, as a second treatment, the surface of the heat-treated titanium alloy plate is degreased and cleaned by a known method, and the degreased titanium alloy plate is treated with 10 mt/l of formalin, 10 t/l of acidic ammonium fluoride, and gluconic acid. ) IJum 3 Q
Activation is performed by immersing in a solution of fil for 25 minutes at room temperature. Subsequently, after washing the activated titanium alloy plate with water, P(3CNH5)IIc1220y/l, NHu
C7100y/l, NiC726H2O30y/L
and a solution of brightener 10y7t with NH4OH p) (8
Using a known palladium alloy plating bath adjusted to
After plating for a few minutes, an elegant white palladium alloy plating with a glossy appearance was obtained. Further, when the titanium alloy plate plated with palladium alloy was bent at 90°, no abnormality was observed in adhesion.

The second example is an eyeglass frame made of titanium.
As a first treatment, heat treatment is performed in the atmosphere at a temperature of 250° C. for 20 minutes. Next, as a second treatment, the surface of the heat-treated titanium alloy plate was degreased and cleaned by a known method, and then treated with 5 y/l of hydrazine, 10 y/l of sodium fluoride, and 50 y/l of sodium citrate. IA/ using the solution of /1
Activation is carried out by electrolysis for 2 minutes under the conditions of dj'n. Next, eyeglass frames made of activated titanium are plated with palladium alloy using a palladium alloy plating bath in the same manner as in the first embodiment.

Furthermore, a solution of KALI (CN) 210 fiA and ammonium citrate 100 y/l was diluted with citric acid to pH 4.
Using a known gold plating solution adjusted to 0.0 and added with a brightener of 0.5 f/l, eyeglass frames plated with palladium alloy were plated for 15 minutes at a temperature of 60°C, 0, and 51 v'dm. When tested, no abnormalities in gloss or adhesion were observed even after 2 years.

In the third example, the same titanium alloy plate as in the first example is used, and activation is performed in the same manner as in the first example through the first treatment and the second treatment. Next, the activated titanium alloy plate was
Using the same gold plating solution as in the second example, the temperature was 60°C.
When plating was carried out for 20 minutes under conditions of , Q, 5 A/dj'rL, a gold plating with an elegant appearance was obtained and the adhesion was perfect.

The fourth example uses the same titanium alloy plate as the first example, performs the first treatment under the conditions shown in Figure 1, and then performs the second treatment.
As a treatment, a heat-treated titanium alloy plate was treated with 10 fil of acidic ammonium fluoride and 10 fil of sodium hypophosphite.
Activation is performed by cathodic electrolysis using a solution of fi and 30 fil of sodium citrate at a temperature of 40° C. and 0.5 fi, /dyn for 3 minutes. Subsequently, the activated titanium alloy plate was plated for 20 minutes under the condition of 2 A/dnL using the same palladium alloy plating bath as in the first example, and as shown in FIG. In the case of ゜, the adhesion of the plating layer was poor when the heating time was 2 minutes or when it was heated in a non-oxidizing atmosphere, but under other conditions, the palladium alloy plating had excellent adhesion and appearance. Obtained.

The activation liquid used in the second strip in the first to fourth examples described above was tested under the conditions shown in FIG. As a result, if an activation solution is used that does not contain either a water-soluble reducing agent or a soluble salt of titanium, the activation effect of titanium will be lost, resulting in incomplete adhesion. Obtained.

In addition, sodium hypophosphite and sodium borohydride, which are used in electroless plating, can be used as water-soluble reducing agents, and although they are effective even when added in a small amount of 0.5 W/l, electrolysis or The immersion treatment time is too long, which is not economical, and is preferably 5% or more.

Further, the soluble salts are preferably sodium fluoride, acidic ammonium fluoride, sodium borofluoride, etc., and even a small amount of 0.0 to 1 f/l is effective, but the treatment time is longer, so preferably 1.0 f/l is added. , Ot/ or more is better. or,
There are conditions under which good results can be obtained using sulfuric acid, hydrochloric acid, etc., but this is not preferable because the titanium oxide will not be eluted unless the treatment temperature is high and the treatment time is not long.

〔Effect of the invention〕

As explained in detail above, the present invention applies a heat treatment to a product made of titanium or a titanium alloy in the air or in an oxidizing atmosphere at a temperature of 100 to 600°C to form a multistable oxide film on titanium. Or made on the surface of titanium alloy,
Furthermore, by removing the oxide film with a treatment solution containing 1.0 f/ or more of a water-soluble reducing agent and a soluble salt of titanium and having a pH of 10.0 or less, the adhesion is perfect and the gloss is improved. Noble metal plating can be performed.

Further, it is possible to provide a noble metal decorative product with an elegant appearance, excellent gloss, color tone, and conductivity at a low cost without impairing the corrosion resistance and lightness of titanium materials.

[Brief explanation of the drawing]

Claims (1)

[Claims] A titanium or titanium alloy material is heat-treated in the air or an oxidizing atmosphere at a temperature of 100 to 600°C, and the heat-treated material contains a water-soluble reducing agent and a soluble salt of titanium as the main components. A direct bright noble metal plating method for titanium or titanium alloy, characterized in that the noble metal is plated directly on the titanium or titanium alloy material after immersion or electrolysis using a treatment solution with a pH of 10.0 or less.