JPS6233315B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to portable exterior parts.

[Prior Art] Conventionally, gold plating has been commonly used as a surface treatment for gold-colored portable exterior parts. On the other hand, due to recent advances in ion plating technology, the golden titanium nitride coating, which is hard and has excellent wear resistance, is attracting attention as a new coating that can replace gold plating.

[Problems to be solved by the invention] However, since conventional gold plating has a low hardness of around HV150, it is easily worn out, and it is necessary to use gold plating to prevent the appearance quality from deteriorating when carried for a long period of time. Although it is necessary to increase the thickness of the plating layer, guaranteeing the above-mentioned quality has the serious drawback of making the cost of gold plating extremely high due to the recent rise in the price of gold. On the other hand, the titanium nitride coating produced by the ion plating method uses titanium, which is much cheaper than gold, as the main raw material, and therefore can significantly reduce manufacturing costs. However, although the color tone is golden, it is not completely the same as the color tone of gold or gold alloy, and the commercial value is low, especially in the case of portable exterior parts such as watches, where the commercial value is influenced by the appearance. It has not yet become a substitute for gold plating.

SUMMARY OF THE INVENTION The present invention is intended to solve these conventional problems, and its purpose is to provide a gold-colored portable exterior component that is low in cost and has excellent durability.

[Means for Solving the Problems] The portable exterior component of the present invention includes at least a titanium nitride layer formed as a base layer by an ion plating method on the surface of the base material of the exterior component, and a titanium nitride layer formed on the base layer by an ion plating method. It is characterized by comprising a nickel layer as an intermediate layer, a gold layer formed on the intermediate layer, and a gold-nickel-indium alloy layer as a finishing layer formed on the gold layer.

[Function] Titanium nitride, which is formed as the base layer of the exterior component base material, has Hv2000, which is much harder than gold, and its wear resistance is extremely superior to gold and gold alloys.
When gold or gold alloy is plated on this titanium nitride layer, the wear resistance of these plated layers is influenced by the underlying layer, making it difficult for scratches to occur, and the wear resistance is improved. However, the adhesion between the titanium nitride layer and the gold plating layer is poor, and these layers tend to peel off easily, making it impractical. In order to improve the adhesion between the titanium nitride layer and the gold layer, it is necessary to provide an intermediate layer with excellent adhesion to each of these two layers. Titanium nitride and gold have a small chemical affinity, but
Titanium nitride and nickel are compatible and have extremely strong chemical bonding strength. Nickel and gold form a solid solution with each other, and their chemical bonding strength is also extremely strong. For this reason, nickel is suitable for the intermediate layer. By using nickel as the intermediate layer, we were able to create a gold-colored exterior component that does not deteriorate in appearance quality even when carried for long periods of time. Moreover, the gold alloy layer as a finishing layer not only has good adhesion to the gold layer, but also has higher hardness and wear resistance than the gold layer, and can produce a golden color tone that is excellent in terms of design. That is, the present invention eliminates the drawbacks of the prior art by forming the surface coating of the exterior part into four layers of titanium nitride, nickel, gold, and gold-nickel-indium alloy, without losing any of the characteristics of the titanium nitride film, and The object of the present invention is to provide an exterior part having an appearance completely equivalent to that of gold plating.

Here, the ion plating method and its effects will be briefly explained. The ion plating method is a method in which the substrate is used as a cathode and the evaporation source is used as an anode in a reduced pressure gas atmosphere of about 10 ^-3 to ^{10 -5} torr, and a high voltage is applied between them to generate a glow discharge, that is, to ionize the gas. Make it into a plasma state. When the object to be treated is connected to the cathode and the coating material is heated and evaporated from the evaporation source,
The evaporated coating material is ionized by the plasma generated in the vacuum chamber, accelerated by the electric field, and deposited on the surface of the workpiece. The evaporated coating material has a short mean free distance and repeatedly collides with each other and deposits on the object to be treated. Therefore, the coating material is deposited on the sides, back surface, and holes of the object to be treated, resulting in extremely good coverage of complex shapes. Also,
Since the kinetic energy of the evaporated material is very high, a dense film can be obtained and its adhesion is also good. Furthermore, as other effects, a reaction ion plating effect in which ionized gases react with each other and a sputtering effect in which the adhesion of the ionized gases is improved are added. Furthermore, since the coating material is evaporated and supplied, the deposition rate is fast and a thick coating can be formed in a short time. In this way, the ion plating method has many advantages over the conventional gas phase coating method.

[Example] A detailed explanation will be given below with reference to examples.

FIG. 1 is an example of an ion plating apparatus for surface-treating exterior parts of the present invention. Vacuum chamber 1
After evacuating the inside using the exhaust system 2, argon gas is introduced from the gas inlet 3 to maintain the vacuum chamber 1 at around 2×10 ^-4 torr, and the ionization electrode 6 is heated to +30 to
+60V is applied, and a voltage of -400 to -1200V is applied to the board 5 with a stainless steel watch case attached to the power supply K.
After applying nitrogen gas, nitrogen gas is introduced from the gas inlet 3 to maintain the degree of vacuum in the vacuum chamber 1 at 6×10 ^-4 torr, and the evaporation source 4 into which titanium is inserted is heated by the power source B to evaporate the titanium. Nitrogen and titanium are reacted to generate titanium nitride, and titanium nitride is vapor-deposited on the surface of the watch case while accelerating the generated titanium nitride using an electric field. Reactive ion plating was performed for 20 minutes at a production rate of 1 to 50 Å/sec to form a titanium nitride layer with a thickness of 0.1 to 6 μm and Hv = 2000. As a result, a watch case with a bright golden color was obtained. Next, this titanium nitride coating was immersed in sulfuric acid containing 15% hydrofluoric acid for 3 minutes to perform an activation treatment, followed by nickel sulfate 30g/, sodium hypophosphite 20g/, and sodium acetate 14g/
, sodium citrate 24g/, ammonium chloride 5g/, lactic acid 0.5g/ in a 40℃ composition bath.
Electroless plating was performed by dipping for 30 seconds to form a nickel layer of approximately 3000 Å on the titanium nitride layer.

Furthermore, gold potassium cyanide 2g/, ammonium chloride 75g/, sodium oxalate 50g/
Approx.
A 1500 Å 24k gold layer was formed on top of the nickel layer. followed by gold potassium cyanide as a finishing layer
10g/, citric acid 90g/, nickel cyanide
0.5g/, indium cyanide 15g/45℃
A strike layer of gold-nickel-indium alloy was formed on the gold layer by electroplating in a composition bath.

The main points regarding the characteristic evaluation of the present invention will be specifically described below. The surface-treated watch case has a golden appearance and does not change color in a corrosion resistance test of immersion in artificial sweat and artificial seawater for 24 hours, and even in a thermal shock test of constant rapid cooling from 30°C and a bending test of 90°C, it remains nitrided. No peeling occurs between the titanium layer and the nickel layer, and between the nickel layer and the gold layer. In addition, in wear resistance tests, the gold layer and the gold-nickel-indium alloy layer can withstand at least 3,000 wears, and the titanium nitride layer as the base layer can withstand 30,000 wears without exposing the base material at all. The appearance was the golden color of titanium nitride and there were no problems at all.

[Effects of the Invention] The present invention provides a gold-colored exterior component with low cost and excellent durability by using a four-layer structure of surface treatment: a titanium nitride layer, a nickel layer, a gold layer, and a gold-nickel-indium alloy layer. made possible. The titanium nitride layer as the base layer is not only golden in color and has excellent wear resistance, but also improves the durability of the gold layer and gold alloy layer. Provides durability equal to or greater than conventional products. The intermediate layer and the nickel layer enhance the adhesion between the titanium nitride layer and the gold layer. The gold layer functions as an intermediate layer between the nickel and the gold alloy layer, and also provides high commercial value to portable exterior parts due to the excellent corrosion resistance and color tone that gold itself inherently has. Next, the gold-nickel-indium alloy layer as a finishing layer is harder than the gold layer and has excellent abrasion resistance, as well as excellent corrosion resistance and a rich variety of elegant color tones, which together with the gold layer make it suitable for mobile exteriors. Add high commercial value to parts. As described above, the portable exterior parts according to the present invention are gold-plated exterior parts that have the same appearance as the conventional expensive gold-plated exterior parts, and have excellent hardness, corrosion resistance, and wear resistance by using a titanium nitride layer as the base layer. has become possible to provide at low cost. The present invention is a new technology that can replace conventional general gold plating, and has extremely large industrial value.

[Brief explanation of the drawing]

FIG. 1 is a simple cross-sectional view of an ion plating apparatus for providing the exterior parts of the present invention. 1... Vacuum chamber, 2... Exhaust system, 3... Gas inlet, 4... Evaporation source, 5... Board (watch case).

Claims (1)

[Claims] 1 At least a titanium nitride layer formed as a base layer on the surface of the exterior component base material by ion plating, a nickel layer as an intermediate layer formed on the base layer, and a nickel layer formed on the intermediate layer. A portable exterior component comprising a gold layer and a gold-nickel-indium alloy layer as a finishing layer formed on the gold layer.