JPS6075571A - External parts for timepiece having golden crystal pattern - Google Patents

Abstract

PURPOSE:To form simultaneously a golden hard nitride layer and a crystal pattern on the surface of each of external parts for a timepiece made of Ti or a Ti alloy by heating the parts to a specified temp. in a gaseous nitrogen atmosphere under high pressure. CONSTITUTION:External parts for a timepiece are made of Ti or a Ti alloy such as a Ti-Mo alloy, they are put in a pressure vessel, and gaseous nitrogen is introduced into the vessel. The parts are held under >=1,000kgf/cm<2> high pressure for >=3hr while heating the parts to the transformation point of the metal or above at 500 deg.C/hr heating rate. A golden hard nitride layer and an iris crystal pattern are formed on the surface of the metal, and fine external parts for a timepiece are obtd. The parts are not corroded by sweat, etc. and are not scratched by contact with other material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exterior part for a watch using titanium or a block titanium alloy having a golden crystal pattern.

In addition, by inserting a watch exterior part previously processed from titanium or titanium alloy into a high-pressure nitrogen gas container,
This invention relates to an exterior part for a watch, characterized in that a golden hardened layer and a crystalline pattern are simultaneously formed on one surface by heating above the transformation point and applying pressure.

Conventionally, exterior parts for watches have mainly been plated stainless steel, brass, nickel silver, etc., and other case materials include cemented carbide, plastic, etc.

Aluminum, titanium, etc. are used in some parts of lightweight alloys and L7, but aluminum has problems such as corrosion resistance, and recently titanium has begun to be mined as a promising lightweight alloy. However, titanium and titanium alloys have poor processability, especially machinability, low hardness and are easily scratched, and even have poor color tone. Despite their excellent chemical properties, they have poor mechanical properties. However, there were problems in terms of decoration, which put a brake on expanding its use.

The present invention was made in view of these drawbacks, and is required for decorative parts such as exterior parts for watches.

(1) The surface must be beautiful (2) It must not be corroded by sweat etc. during use (5) During use,
The object of the present invention is to provide a new titanium or titanium alloy exterior part that satisfies the main characteristics of not causing scratches on the surface due to contact with hard objects and has excellent peg decorative properties.

Next, to explain the present invention in detail, when a thionic titanium alloy is heated above its transformation point, crystal grains coarsen and corrosion occurs at the grain boundaries and within the grains, and first, clear crystal grains appear on the surface. As a result, grooves with a certain depth and width are formed in one direction within the grain.

These grooves act as a type of diffraction grating, and the direction of the grooves differs depending on the direction of the crystal, so when the material is observed from a certain direction, the crystals emit an iris. It is also possible to produce a titanium exterior part having an iris crystal pattern using such a simple method. However, with this alone, the surface is not hard enough to withstand practical use, and it is easily scratched and scratched during use, reducing the decorative effect of the cut corners.

Therefore, the present invention heat-treats titanium or a titanium alloy in a high-pressure container in a nitrogen atmosphere, thereby promoting the reaction between titanium or titanium alloy and nitrogen gas, and forming an ultra-hard gold-colored nitride layer on the surface. It made things possible.

The high-pressure processing technology used in the present invention is often used for pressure sintering of powder materials, removal of internal defects in sintered crystals and forged products, etc., and has already achieved great results. The use of this method to form a nitride layer and to simultaneously form a decorative gold color and a crystal pattern is completely new, and many effects not previously available can be expected.

Next, we will discuss the high-pressure processing conditions used in the present invention: Belt pressure: De I, Te: H: 100 Kq, f/Crn: 2 or more, Desir: L < f
d 100GK9f/Cm 2 or more is effective. 1
Although a gold-colored nitride layer is formed even at 00 Ky f/am2 or less, the nitride φ layer is thin and cannot satisfy the characteristics required as an exterior part for a watch. Regarding the temperature, it is desirable to crystallize at a temperature above the transformation point of the titanium or titanium alloy used as the material and below 1300°C.
If the temperature exceeds 0°C, the crystal grains will become too coarse and the strength will become brittle, making it impossible to meet the required standards for exterior parts for watches.

The present invention will be described in detail below with reference to Examples.

Example-1 A watch case and dial made of pure titanium were placed in a high-pressure container, and then nitrogen gas was inserted and heated for 50 minutes.
The temperature was raised at a heating rate of 0°C/h, and the temperature was 1000"C, FE
Jll 500 Ky When I got to 2nd floor, I stayed on my back for 3 hours. Thereafter, it is cooled to room temperature, the pressure is released, and the sample is taken out from the high-pressure container. The pure titanium case and dial treated in this way have a golden hard nitride film layer of 3 to 5 microns on the surface, and a crystal pattern with an average grain size of 1 to 21 m is formed at the same time, creating an unprecedented decoration. It was effective. In addition, the surface hardness is extremely hard with Hν (over 300), and in terms of functionality and quality, it exhibits excellent properties that cannot be obtained with conventional pure titanium.Furthermore, the surfaces of both the case and dial are polished by 2 to 3 μm to eliminate the recesses. The golden crystals and the titanium colored crystals on the protrusions are naturally combined to create an even more decorative effect.

Example-2 Preliminarily containing 30% molybdenum at 1% weight = 5
- A watch case made of titanium and molybdenum alloy is placed in a high-pressure container, and after 17 hours, it is heated for 60 hours while nitrogen gas is inserted.
The temperature is increased at a heating rate of 0°C/h, and the temperature is 1050°C and the pressure is 1.
It will last for 4 hours when it reaches 500KI if 76m2.

Thereafter, it is cooled to room temperature, the pressure is released, and the sample is taken out.

In the titanium alloy case treated in this way, a hard golden nitride film layer of 3 to 5 microns is formed on the surface as in Example-1, and at the same time a crystal pattern with a grain size of 2 to 3 +o+ appears. Dekifc.

The titanium alloy case completed in this way has a new and unprecedented decorative feature that takes full advantage of the material's excellent corrosion resistance.

In the above examples, only pure titanium and titanium-molydene alloys were described, but similar effects can be obtained with other titanium alloys, and by changing the processing conditions, the crystal grains can be freely selected. Therefore, the present invention has succeeded in significantly expanding the application of titanium alloys to exterior parts for watches17.

In addition, an all-titanium watch using titanium in the band as well as the case and dial is manufactured according to the present invention, and
R has also made it possible to provide a watch that is lightweight, scratch-resistant, and highly decorative, and can be used in a wide range of applications, including sports watches. In addition to watches, it can also be used for decorative items such as eyeglass frames, cufflinks, lighters, etc. to achieve the same effect as watches.

From then on, soil Applicant: Suwa Seikodai Co., Ltd. Agent Patent Attorney Mogami 7- 397-

Claims (1)

[Claims] A golden crystal in an exterior part for a watch using titanium or a titanium alloy as a material, the titanium or titanium alloy being heated above its transformation point and pressurized in a high-pressure container in a nitrogen gas atmosphere. Exterior parts for watches with patterns.