JPH0534310B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a decorative golden member formed by applying a coating layer containing titanium nitride as a main component to the surface of a ceramic body.

Since ancient times, humans have prized gold as the most noble thing. It exhibits a brilliant golden color, does not rust even when left in the air for a long time, is highly chemical resistant, and maintains its golden color forever, so it is used as ornaments and coins. has been used.

However, such gold is extremely expensive because it is produced in small quantities, and it also has the disadvantage of being prone to wear due to its high specific gravity and low hardness.

In order to avoid this situation, it has been a practice since ancient times, especially for decorative items, to form the base from other inexpensive metal materials and then apply gold plating or gold plating to the surface to give it the same appearance as gold products. With this, we have met the desires of most people.

However, since these gold-plated or gold-plated products still use gold, they are not only expensive, but also cause pollution when gold-plated and cause scratches on the gold-plated parts that reach the base metal. If the gold plating layer is worn away at the edges, the base metal will be exposed and the appearance will become unsightly and the decorativeness will be lost. Corrosion of the bare metal is accelerated by the contact potential difference between the gold plating layer and the gold plating layer, which eventually peels off.

Such occurrence of scratches and wear on the gold plating layer is due to the fact that gold itself is a soft material, and can be said to be the fate of gold.

Therefore, among metal nitrides and metal carbides, which emit a brilliant color tone equivalent to gold, have high corrosion resistance and great abrasion resistance, and are processed using non-polluting technology and are inexpensive, Bitker is a particularly brilliant golden color. Titanium nitride (hereinafter referred to as TiN) with a hardness of 2450 (hereinafter referred to as HV) is sintered into the desired shape,
Efforts have been made to polish the surface and make decorative items.

However, TiN alone does not sinter, and TiN
The powder is usually mixed with 10 to 20% of other raw materials as sintering aids, and the powder is press-molded into the desired decorative shape. After sintering in a vacuum or nitrogen gas atmosphere at approximately 1800°C, the surface is mirror-finished. It is manufactured by polishing, but the hardness must be around HV1500 due to the addition of sintering aids. Since it is a sintered body containing a mixture of high-hardness TiN particles and relatively low-hardness additives, it is extremely difficult to polish the surface to a mirror finish. In addition, TiN is about 10 times more expensive than the commonly used alumina ceramic raw material, and requires the use of a special vacuum furnace for sintering, making the final product cheaper than gold. Although it is a metal, it does not have many merits, such as having a product price comparable to silver, so its uses have been severely limited.

Therefore, in order to make effective use of TiN, which has a golden color, without using any gold, we created the desired ornament shape from stainless steel, etc., and applied it to the surface.
A coating layer of TiN has been deposited by ion plating. This in-on plating method is a type of physical vapor deposition method, which allows the TiN layer to be deposited on the deposition surface at a high speed, allows the thickness of the TiN layer to be freely controlled, and introduces a reactive gas when depositing TiN. By controlling the partial pressure of nitrogen gas, it is possible to freely obtain a whitish golden color, a bluish golden color, a yellowish golden color, etc. by controlling the partial pressure of nitrogen gas. . In addition, although the TiN coating layer has a high hardness of HV2.200, which is close to the original hardness of TiN, the most ideal coating layer is one made by improving the hardness by applying optimal heat treatment to the corrosion-resistant stainless steel that is currently considered the most ideal base. but
It has a hardness of about HV450, which is much lower than a TiN coating layer, and decorative items coated with a hard TiN coating layer on this base have high durability against scratches, but are weak against bruises and easily get dented. There is a high possibility that the coating layer will continuously peel off due to some of the dents.

In addition, as long as the TiN coating layer exhibits a golden color, it is preferable that it be as thin as possible in order to shorten the deposition processing time and save raw materials.
As the TiN coating layer is thinner, the color of the underlying metal may change due to transmission or reflection.
This will bring about a subtle influence and change in the golden color of the TiN coating layer.

The present invention is a decorative golden member developed in view of the above circumstances, and embodiments of the present invention will be described in detail.

The present invention is a decorative golden member characterized in that a coating layer mainly composed of TiN is coated on the surface 2 of an alumina (Al ₂ O ₃ ) ceramic body 1, as shown in a partial cross section in the figure. The ceramic body 1 forming the base is prepared by mixing and stirring a small amount of a caking agent, a binder, a sintering aid, etc. into a raw material fine powder mainly composed of alumina, and then forming the mixture into a desired shape. For example, according to the dry pressure molding method, raw materials are filled into a mold, pressure is applied from the top and bottom or from only one direction, and the molded product is fired in an oxidizing atmosphere at a temperature of 1,600°C or higher. A ceramic body 1 having the shape is obtained.

There are various molding methods to obtain a molded product before firing, such as extrusion molding, injection molding, tape molding, casting method, and potter's wheel molding, but the most suitable method depends on the shape to be molded, the properties of the ceramic, etc. A molding method may be used.

The alumina ceramic body as a sintered body thus fired exhibits a white to ivory color unless a special coloring agent is added. This is TiN
This is the ideal base color for applying a thin coat to obtain a beautiful golden color. In addition, its hardness is
It has an extremely hard HV2.000 and is similar to a TiN coating layer. The surface 2 of the alumina ceramic body 1, on which the alumina ceramic body 1 is used as a base and on which the coating layer 3 described later is applied, is polished to a mirror-like state with extremely flatness, and the coating layer has a brilliant and bright golden color. The flatness (surface roughness) exhibited by 3 is approximately
It was confirmed by preparing a wide variety of samples and performing visual tests on them by a large number of people that a thickness of 4.5 μm or less is preferable.

Next, the coating layer 3 that is coated on the surface 2 of the alumina ceramic body 1 and has a golden color is made of TiN.
The main component is carbon C, etc., or it is deposited on the surface 2 by, for example, an ion plating method. In this case, deposition is not limited to the ion plating method, which involves operations such as changing the amount of N ₂ gas as a reactive gas, but a similar method such as vapor deposition sputtering, or a chemical vapor deposition method may also be used. , base ceramic body 1
Since TiN has extremely small thermal expansion and excellent corrosion resistance and heat resistance, it is possible to firmly adhere the TiN coating layer 3 using any of the deposition methods.

By the way, the thickness t of the coating layer 3 mainly composed of TiN, which is applied to the surface 2 of the alumina ceramic body 1, is set to such an extent that the splendid golden color tone is not lost in terms of application time and material quantity, that is, cost. It is desirable that it be as thin as possible. Therefore, we prepared 7 test pieces of alumina ceramic body 1 with an ivory color as a base and a surface 2 roughness (average value) of about 1 μm, and compared them with the same
Under the same conditions in an N ₂ gas atmosphere, the thickness t of the TiN coating layer 3 is approximately 0.5, 1, 2, 3, 4,
As a result of sensory tests and physical tests on the color tone and properties of the golden member made by coating each of
It was confirmed that the slightly translucent material was highlighted by the ivory color of the base alumina ceramic body 1, and exhibited a brilliant golden color. On the other hand, as the thickness t of the TiN coating layer 3 increases from 5 μm to 6 μm,
It became a slightly dull golden color, which is the original color of TiN, and many viewers indicated that it was not suitable as a decorative material.
In addition, among the physical tests, the peeling test and scratch test (scratches and scratches) do not peel off easily, and even when scratches occur, it is only a test of scratching with ordinary steel or wiping silica sand powder. I was unharmed. This is TiN coating layer 3
Alumina ceramic body 1 with hardness similar to
This is thought to be because it is used as a base.

In addition, as part of a corrosion test, the weight loss was measured after being immersed in a 60% by weight nitric acid boiling solution for 24 hours, and the weight loss was 0.15 [mg/cm ² day], which was extremely stable. . However, coating layer 3
In the case where the thickness t was 0.5 μm, it was observed that the golden color changed to a slightly faded color tone.

Furthermore, artificial sweat was applied to the surface of the coating layer 3, and it was left in an atmosphere with a humidity of 90% or more for 20 days.
No corrosion, stains, etc. were found on any of the test pieces.

As described above, the golden member according to the present invention uses a white to ivory colored alumina ceramic body as the base, and a coating layer mainly composed of TiN of 4 μm or less is applied to the highly polished surface of the alumina ceramic body. It emits a brilliant golden color, is resistant to corrosion, scratches and bruises, and is inexpensive, so it can be applied to a variety of decorative items.

[Brief explanation of the drawing]

The figure shows an enlarged cross section of a portion of a decorative golden member according to the present invention. 1...Alumina ceramic body, 2...Surface, 3
...Coat layer.

Claims (1)

[Claims] 1. A decorative golden member characterized in that a coating layer containing titanium nitride as a main component and having a thickness of 0.5 to 4 μm is applied to the surface of a white alumina ceramic body that has been previously polished to a mirror finish.