JPH06293579A - Production of colored ceramics - Google Patents

Abstract

PURPOSE:To color a ceramic material without mixing a color into the ceramic material or without applying a coating material on the surface. CONSTITUTION:A ceramic material is made to develop a color by irradiating a molding or powder of the ceramic material with radiation (gamma-ray). The exposure dose of the gamma-ray is about 25KGy which is enough to develop a color. With the more exposure, the color becomes more dense.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a colored ceramic material, and more particularly to a method for coloring a ceramic material without blending the ceramic material with a coloring agent or applying a coating material.

[0002]

2. Description of the Related Art Conventionally, as a method of coloring a ceramic material, for example, a coloring agent (for example, lead, cobalt, iron, chromium, manganese, or an oxide thereof) is added to the base material of the ceramic material, and molding is performed. Those that are made to develop color by firing afterwards A mixture of glaze (pigment) with a desired color-forming agent that is baked on the surface of the ceramic molded product to be colored After firing the molded product made of ceramic material The surface of the ceramic molded product is colored by applying an organic paint, etc. Other oxides, metals, etc. are coated on the surface of the ceramic sintered body by the sputtering method, vacuum deposition method, ion plating method, etc. Those that are colored by the above are generally known.

[0003]

However, in the case where the coloring agent is added to the ceramic raw material substrate, uneven coloring is generated in the ceramic molded product due to uneven firing temperature and firing atmosphere in the firing line, and the coloring agent is added. There is a problem that it acts as an impurity (sintering inhibitor) and causes deterioration of various characteristics such as a decrease in density and a strength depending on the material, and the target product and use conditions are restricted. In addition, in the method of coloring with a glaze (pigment), it takes time and labor to obtain a product because a step of applying the glaze on the surface of the ceramic molded article and a step of firing this at a high temperature are required.

Further, the method of coloring with an organic coating has a problem that the compatibility between the ceramic and the coating film (coating property) is poor and the coating is immediately peeled off, and it cannot be used in applications where the contact with the coating is unfavorable. It was Furthermore, the sputtering method,
It is difficult to uniformly coat the entire surface of a ceramic molded product with a coloring method such as a vacuum vapor deposition method or an ion plating method, and it is very difficult to coat a complicated part especially with a complicated shape. there were. In addition, the treatment cost is generally high, and the chemical resistance is inferior. Therefore, the target products are limited.

The present invention has been made in view of the above problems, and an object thereof is to apply a paint or the like to the surface of a ceramic material without adding a color former to the ceramic material. In other words, it is to make a molded article or a granular material made of a ceramic material color by a simple method. As a result, it is possible to avoid the deterioration of mechanical properties due to the mixing of the coloring agent into the ceramic material, to maintain the permanent coloring state and to apply it to various shapes, such as ceramics, artificial jewelry, rings, tie pins, pendants, etc. It is intended to be applied to various accessories or special applications such as artificial bones and IC packages.

[0006]

In order to achieve this object, the method for producing a colored ceramics according to the present invention is characterized in that the ceramics material is colored by irradiating the ceramics material with radiation. Is. The term "ceramics material" as used herein includes sintered compacts of ceramic molded products and ceramics granules, and is more crystalline than non-quality (glassy) ones, especially polycrystalline ones. It is highly useful in the body.

[0007]

EXAMPLES Examples of the present invention will be described in detail below. (Ceramics Sintered Body) Table 1 shows the test results for the sintered bodies of the ceramic molded products. Table 1 shows the names, compositions, and firing temperatures of various ceramic materials used in the test. The results of irradiating the sintered body obtained by firing with radiation (γ ray) are also shown in Table 1. Irradiation with γ-ray is cobalt 60
It was performed using an irradiation device. The irradiation dose of γ-ray was 25KGy (2.5Mrad) for the time being. Specifically, 10KGy
The gamma dose of / Hr. Is irradiated for 2.5 hours. 1 Gy here
(International System of Units) is a unit of absorbed radiation dose and means the dose when there is 1 joule of energy absorption per kg of substance. The conversion of this to "rad" is 1 Gy = 10
0rad, therefore 25KGy = 2.5 × 10 ⁶ rad (= 2.5
Mrad).

As a result, as shown in Table 1, the alumina-based ceramics sintered body, which was originally white, developed a light yellowish brown color. In addition, apatite-based ceramics, which were originally bluish white, changed to a deep blue solid color, and zirconia sintered bodies were originally a white but developed amber. It is a major feature. It is considered that such a coloring phenomenon is caused by irradiation of the ceramic material with radiation (γ-rays) to generate lattice defects in the crystal and trap electrons and holes in the defects.

With respect to the zirconia ceramics sintered body, various characteristics (bending strength, constitution of crystal phase and surface roughness) before and after γ-ray irradiation were compared, and the results are shown in Table 2. As a result, the bending strength was comparable to that before γ-ray irradiation. As for the crystal phase, as a result of measurement by X-ray diffraction, it is clear that the crystal phase does not change before and after irradiation and is composed of a monoclinic crystal of 0%, that is, a tetragonal crystal of almost 100%. This means that, for example, when this zirconia ceramics sintered body is heat-treated later or is used in a stress-loaded state, there is a possibility that the durability may be deteriorated due to load cracks accompanying the ablation transformation of the crystalline phase. Means less. In addition, the result that the difference in the surface roughness was not significant was obtained. Note that the shade of color can be freely adjusted by changing the irradiation dose of γ rays. For example, when the zirconia ceramics sintered body was irradiated with a γ-ray irradiation amount of 50 KGy (double amount), the color was further developed.

[0010]

[Table 1]

From these test results, a ceramic material that develops color upon irradiation with γ-rays is applied to ceramics and various accessories, and this type of ceramic material is molded and sintered into a desired shape and then irradiated with γ-rays. Colors such as tan, deep blue or amber are obtained. The hues of these colors can be changed from dark to light by appropriately changing the γ-ray irradiation amount.
Further, by appropriately mixing such ceramic materials or by selectively using the ceramic materials partially in the molded product, it is possible to change the color shade and express a color pattern. Even a ceramic molded product having a more complicated shape has a strong γ-ray penetrating power, so that a uniform color can be developed. Although not shown in the table, it was also confirmed that a uniform color was developed up to the inner surface of the pores of the porous (porous) molded product (baked product).

Further, among the ceramic materials shown in Table 1, zirconia ceramics is particularly used for artificial bones and the like. This zirconia artificial bone is usually steam sterilized, and the sterilization operation is performed by γ-ray irradiation. Then, since the color is developed by γ-ray irradiation, it is possible to easily visually judge whether the product has been sterilized or not, and there is an advantage that product management can be properly performed. Further, as explained in Table 2 above, there is no difference in the characteristics (strength, phase change, etc.) of the zirconia ceramics before and after the γ-ray irradiation, so that it can be applied with confidence.

[0013]

[Table 2]

(Ceramics Granules) Table 3 summarizes the test results for the ceramics granules.
Table 3 shows the name, composition, and radiation (γ-ray) irradiation result of this granular ceramic material. The γ-ray irradiation conditions are the same as in the case of the above-mentioned ceramics sintered body.
The irradiation dose is 5KGy. In this case as well, γ of 10KGy / Hr.
The dose has been irradiated for 2.5 hours. The ceramic powder particles used here are all crystalline.

Thus, even in the case of ceramic powder,
For example, for alumina-based or silica-based ceramics, coloring was observed as shown in the table. Therefore, the present invention is also applicable to the use of ceramic powder or granules, for example, by coating the powder or granular material of such a ceramic material on the surface of an object to be irradiated, such as powder coating, and then irradiating with γ-rays to develop color. It is clear that can be applied.

[0016]

[Table 3]

[0017]

EFFECTS OF THE INVENTION As is clear from the above description, according to the present invention, a coloring agent is mixed in a ceramic material, a glaze (pigment) or a paint is applied to the surface of a ceramic molded article, or by a sputtering method or the like. Molded product of ceramic material (sintered body) without coating with colorant
Alternatively, the powder or granules are irradiated with radiation (γ-rays) to develop color. Therefore, it can be applied to ornaments such as ceramics, artificial gems, and various accessories by taking advantage of its color characteristics, and its coloring does not impair the mechanical properties. Or, when used as a bone filling material or artificial bone material, not only is there a sterilization effect by γ-ray irradiation, but it is easy to manage the product by judging whether it is sterilized or not. Is useful.

[Procedure amendment]

[Submission date] May 24, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

In order to achieve this object, the method for producing a colored ceramics according to the present invention is characterized in that the ceramics material is colored by irradiating the ceramics material with radiation. Is. The term "ceramics material" as used herein includes a sintered body of a ceramics molded product and a ceramics granule, and is more crystalline than amorphous (glassy) ones, especially polycrystalline ones. It is highly useful in the body.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

With respect to the zirconia ceramics sintered body, various characteristics (bending strength, constitution of crystal phase and surface roughness ) before and after γ-ray irradiation were compared, and the results are shown in Table 2. As a result, the bending strength was comparable to that before γ-ray irradiation. As for the crystal phase, as a result of measurement by X-ray diffraction, it is clear that the crystal phase does not change before and after irradiation and is composed of a monoclinic crystal of 0%, that is, a tetragonal crystal of almost 100%. This can, for example, or heat treatment after the zirconia ceramic sintered body, it is less likely durability reduction due to accompanying load cracks in the diffusion transformation of the crystal phase in the case that used in the state of the stressed load Means In addition, the result that the difference in the surface roughness was not significant was obtained. Note that the shade of color can be freely adjusted by changing the irradiation dose of γ rays. For example, when the zirconia ceramics sintered body was irradiated with a γ-ray irradiation amount of 50 KGy (double the amount), the color was developed more deeply.

Claims (4)

[Claims] 1. A method for producing a colored ceramic, wherein the ceramic material is colored by irradiating the ceramic material with radiation. 2. The method for producing a colored ceramic according to claim 1, wherein the ceramic material is a sintered body of a ceramic molded product. 3. The method for producing a colored ceramic according to claim 1, wherein the ceramic material is a ceramic powder or granular material. 4. The method for producing a colored ceramic according to claim 1, wherein the ceramic material is crystalline.