JPS6217040B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in eyeglass frames made of metal members.

Many eyeglass frames use metal members depending on their function and structure. Gold, gold alloys,
Many of them perform electroplating of precious metals such as rhodium and palladium. Of course, as a condition for electroplating, it goes without saying that the base material must be electrically conductive. Titanium and titanium alloys are lightweight, strong, protected by a strong oxide film on the surface, and have good corrosion resistance, making them extremely excellent materials for use as metal members for eyeglass frames. However, even though titanium and titanium alloys are conductive materials, an oxide film quickly forms on the surface during electroplating. This oxide film is not easy to activate and therefore has poor adhesion even when electroplated.
Or the plating peels off due to bending stress during wear.
Unable to maintain beauty. For this reason, eyeglass frames made of titanium and titanium alloy parts can be colored by polishing alone, or if colored, by applying the interference color of an oxide film or painting with paint to obtain a color tone other than that of each white metal. was. However, eyeglass frames made of materials that are difficult to wet plate, such as titanium, titanium alloys, aluminum, stainless steel, and magnesium, cannot be plated with gold, gold alloys, rhodium, palladium, etc., which are normally formed on the base material by wet plating. Therefore, the beautiful color tones characteristic of these precious metals cannot be obtained.

The purpose of the present invention is to overcome the above-mentioned drawbacks and to
To provide an eyeglass frame made of a material that is difficult to wet plate, such as a titanium alloy, by wet plating the surface of the frame with a noble metal, and having good adhesion, excellent corrosion resistance, and the beautiful luster of a noble metal.

Therefore, the present invention provides a
A conductive thin film of TiN, TiC or CrN is attached by dry plating.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 Temples 1 and 1', bridges 2, rims 3 and 3', and butterfly legs 4 and 4' of the eyeglass frame shown in Fig. 1 were made using JIS/H46070 titanium wire TW35, mirror-polished. It was set on a rotating body in a vacuum container with a nitrogen gas atmosphere reduced to 2×10 ^-4 mmHg, and a negative DC voltage was applied to ionize nitrogen by glow discharge, while simultaneously converting titanium into electrical resistance heat in the vacuum container. It was then heated to evaporate and combined with ionized nitrogen to form titanium nitride (TiN) with a thickness of 2 μm over the entire surface of the titanium frame. The electrical resistivity of titanium nitride thin film is 25μΩ. Since it has a conductivity of cm, electroplating is possible using titanium nitride as an electrode. Next, a palladium-nickel (Pd-Ni) alloy was formed to a thickness of 2 μm on the TiN thin film fixed to the titanium frame by the already known electroplating method, and gold plating was further applied to a thickness of 2 μm. A cross section of the temple 1 of the frame thus obtained is shown in FIG. Nickel-Ni is on the titanium base material, palladium-nickel alloy Pd-Ni is on the nickel-nickel, and gold-Au is on the palladium-nickel alloy Pd-Ni. The temple of the eyeglass frame obtained in this way
A 90 degree bending test was performed, but the plating film did not peel off, and even after a 16-hour chass test according to the chass test method in the appendix of JIS.H8617, no discoloration, pitting, or peeling occurred. It had good adhesion and maintained a beautiful golden luster. Furthermore, even when placed in a highly corrosive environment, there was no occurrence of patina or red rust, making it suitable for frames where aesthetics are important.

In addition, to produce a titanium carbide (TiC) thin film on the surface of a titanium frame by vacuum deposition,
It is sufficient to change the nitrogen gas atmosphere in Example 1 to a methane gas atmosphere, and titanium carbide has a low electrical resistivity.
52.5μΩ. cm, the electroplating method similar to Example 1 was performed using titanium carbide as an electrode.
In order to be able to plate precious metals and to generate chromium nitride (CrN) by vacuum deposition on the surface of a titanium frame, titanium was heated in a vacuum container using electrical resistance heat as in Example 1. In contrast to heating and evaporating chromium using electrical resistance heat, chromium nitride can be heated and evaporated using electrical resistance heat, and since chromium nitride has the same electrical resistivity as titanium nitride, it can be plated using chromium nitride as an electrode.

Although vacuum deposition has been described above as an example of dry plating, it goes without saying that various activation reaction deposition methods such as sputtering and ion plating can be used.

The electroplating in the example is gold, but the thin film obtained by dry plating on the surface of the titanium frame is conductive, and activation during electroplating is easier than titanium, and it is suitable for use on eyeglass frames. The noble metal used for plating may be any of gold alloys, platinum, platinum alloys, rhodium, palladium, palladium alloys, etc., and it is of course possible to plate multiple layers of these noble metals if necessary.

Although it is possible to directly plate precious metals on titanium frames by vacuum deposition, it is necessary to plate glasses frames thickly to prevent the base material from being exposed due to wear during wear. Since the shape of the eyeglass frame has a large amount of space, most of the evaporated precious metal adheres to places other than the eyeglass frame, which is economically disadvantageous compared to electroplating.
Moreover, since it is a precious metal, it cannot be dissolved and is not easily recovered.

TiN, TiC, and CrN have good corrosion resistance and a Vickers hardness of about 2000, which is extremely hard, so even if the precious metal film obtained by electroplating is soft, scratches will not spread easily and will not cause scratches. It is not noticeable because it does not reach the base material. Dry plating such as vacuum deposition has good adhesion because the base material is deposited in an activated state, especially when TiN and TiC are deposited.
A solid solution layer of Ti-N or Ti and C is formed under TiN or TiC, which has the advantage of improving adhesion.

In addition, in the example, palladium nickel (Pd
-Ni) alloy was used, but this layer may be omitted.

As described above, according to the present invention, it is possible to perform precious metal plating on a titanium eyeglass frame that cannot be obtained by electroplating alone, and it is possible to obtain a titanium eyeglass frame that is lightweight and maintains the beauty, corrosion resistance, and durability of a precious metal.

The film thickness of titanium nitride, titanium carbide, and chromium nitride is
The thickness is preferably from 0.1 μm to 3 μm, and if it is less than 0.1 μm, it is unstable, and if it is more than 3 μm, the material is brittle, so there is a risk of cracks occurring in eyeglass frames when bending.

Even if the titanium frame is a titanium alloy frame, the purpose can be achieved. titanium nitride, titanium carbide,
After chromium nitride is vacuum-deposited, a nickel film may be obtained by vacuum evaporation on top of the chromium nitride, and the precious metal may be electroplated using the nickel film as an electrode. In this case, activation during electroplating is easier.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a frame, and FIG. 2 is a sectional view of a temple according to a first embodiment of the present invention. Explanation of the symbols of the main parts, 1, 1'...Temple, 2, 2'...Bridge, 3, 3'...Rim,
4,4'...Butterfly foot.

Claims (1)

[Claims] 1. In an eyeglass frame made of titanium or a titanium alloy material, a conductive thin film selected from TiN, TiC, and CrN is formed on the surface of the eyeglass frame, and wet plating is performed on the conductive thin film. Eyeglass frames characterized by being plated with precious metals. 2. Claim 1, characterized in that the noble metal is one layer or multiple layers of one of gold, gold alloy, platinum, platinum alloy, rhodium, rhodium alloy, palladium, palladium alloy, silver, and silver alloy. Eyeglass frames as described in section.