JPH01313355A - Production of colored ceramic raw material - Google Patents

Abstract

PURPOSE:To improve uniform dispersibility and thermal stability of a colorant without impairing purity and particle size being the feature of a fine ceramic raw material by utilizing the integral admixture of base material and the colorant as the colored ceramic raw material. CONSTITUTION:Base material (e.g., Y2O3, partially stabilized ZrO2) and a colorant (e.g., NiO) and if necessary, a dispersion auxiliary are sufficiently mixed and this mixture is dried and thereafter calcined. The calcined material is pulverized and regulated to particle diameter close to submicron. This particle diameter is almost equal to the particle diameter of the base material. Then this powder is dried and thereafter disintegrated to obtain an intermediate raw material. In this case, dispersibility may be enhanced by repeatedly performing the stages from calcination to drying. The above intermediate raw material is formed as an integral material wherein the colorant is incorporated in the particles of the base material. Then this intermediate raw material is mixed with the base material and thereafter this mixture is calcined, pulverized, dried and disintegrated in the same stages as the above-mentioned stages to obtain the colored ceramic raw material.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing colored ceramic raw materials.

(Conventional technology) Conventionally, many products made from ceramics have generally taken advantage of the color of the ceramic fabric, but recently, ceramics, especially fine ceramics, have been applied to general consumer goods. This is becoming more and more popular, and there is a trend to add various colors to ceramics to increase their added value.

Known methods for coloring ceramic products include, for example, applying a coloring agent to the surface of the ceramic product, or mixing a coloring agent into a ceramic powder raw material and sintering the mixture.

Conventionally, one of the latter methods has been to use white fine ceramic base materials (in powder form) such as alumina and zirconia.
It is known that a coloring agent such as cobalt oxide or manganese oxide is added to a ceramic material, the material is molded, and then sintered at a high temperature to obtain a colored ceramic product.

[Problem to be solved by the invention]

However, in the conventional coloring method described above, the ceramic base material and the colorant are often mixed into a slurry, so there is a difference in specific gravity between the base material and the colorant in the slurry. However, due to differences in surface conditions, the colorant may not be uniformly dispersed and the two may separate. As a result, non-dispersion of the colorant occurs in the sintered body, leaving uneven color on the product, and due to this non-dispersion, the strength after sintering is also low.

Therefore, the technical problem of the present invention is to improve the dispersibility and thermal stability as characteristics of colored ceramic raw materials without impairing the purity and particle size, which are characteristics of fine ceramic raw materials.

(Means for Solving the Problems) In order to solve the above problems, the method for manufacturing colored ceramic raw materials according to the present invention provides a primary coloring step of mixing a coloring agent into a ceramic base material, sintering it, and then pulverizing it. and a secondary coloring step in which the intermediate raw material obtained in this primary coloring step is mixed with a ceramic base material and sintered and crushed again to obtain a colored ceramic raw material.

As described above, the present invention consists of a primary coloring step and a secondary coloring step, and in each of these steps, a raw material consisting of a base material and a coloring agent is obtained. Even with the coloring raw material obtained in the primary coloring process, the dispersibility of the colorant is higher than that of conventional colorants, but in the present invention, this is further mixed into the base material as an intermediate raw material and used in the secondary coloring process. This is to obtain a coloring raw material with higher dispersibility, thereby reducing the difference in specific gravity and the difference in surface condition between the base material and the colorant, and making it closer to the base material.

The mixing ratio of the base material and colorant in the primary coloring step,
The mixing ratio of the base material and intermediate raw material in the secondary coloring process is
It can be selected as appropriate.

As ceramic raw materials that can serve as the base material, white ceramics such as alumina (Ai20s) and zirconia (Zr02) are often used.

Furthermore, transition elements such as cobalt oxide, manganese oxide, and nickel oxide, and rare earth elements such as praseodymium oxide and neodymium oxide are often used as colorants.

Next, the manufacturing process of the present invention will be described.

The primary coloring process will be explained based on FIG. 1.

First, the base material, colorant, and dispersion aid are thoroughly mixed, dried, and then fired. This firing temperature varies depending on the base material used. Next, this fired product is pulverized using a side mill or the like to obtain a particle size of about submicron. This particle size is approximately the same as the particle size of the base material. Then, after drying this, it is crushed to obtain an intermediate raw material. Note that the firing and drying may be repeated to improve dispersibility.

The intermediate raw material is formed as an integral product in which a coloring agent is incorporated into the particles of the base material. For example, when alumina is used as the base material and cobalt oxide is used as the colorant and fired,
A colored composition having the following formula will be obtained.

nAJlz03 + CoO+ Coo ΦnAu2
03 And the above CoO・A pattern 203 is the base material Au 2
It is synthesized by firing as a coloring composition in 03.

Next, the secondary coloring process will be explained based on FIG. 2.

The intermediate raw material obtained in the above primary coloring step and the ceramic base material are mixed again, and then similarly to the primary coloring step, the mixture is mixed, fired, pulverized, dried and crushed to obtain a colored ceramic raw material. In addition, the base material of ceramics in the secondary coloring process is
The base material does not necessarily need to be the same as the base material used in the primary coloring step.

For example, 6mou% Y2O3 partially stabilized zirconia is used in the primary coloring process, and 3mofL%Y is used in the secondary coloring process.
There are cases where 2O3 partially stabilized zirconia is used.

When the particles of the colored ceramic raw material thus obtained are schematically shown in FIG. 3, they are obtained as an integral body in which the intermediate raw material 2 is dispersed in the base material 1.

(Example-1) 10% nickel oxide (Nip) was added as a coloring agent to the base material (Y203 partially stabilized ZrO□) and treated in a primary coloring step. The firing temperature was approximately 900° C., and the average particle size after pulverization was approximately 0.71 Lm. Next, 10% of the intermediate raw material was again added to the base material and treated in the secondary coloring step. The firing temperature was approximately 1000° C. The average particle size after pulverization was approximately 0.7 gm.

Next, this colored ceramic raw material was granulated, press-molded, and then sintered at 1500°C for 2 hours in the air to obtain a sample.

As a comparative example, 1% of a coloring agent (Nip) was mixed into the above base material, which was granulated and press-molded in the same manner as the colored ceramic raw material of the above example, and then heated at 1500°C for 2 hours.
A sample was obtained by sintering in the air for a period of time.

Next, Table 1 shows the results of examining the bending strength and appearance of these samples.

Table 1 (Example 2) Manganese dioxide (MnO□) was added as a coloring agent to the base material (All 20:I), and a colored raw material was obtained through the same steps as in Example 1 above. As a comparison, the same amount of manganese dioxide as in Example 2 was added to the above base material and heat treated was obtained at the same time.

Next, the above coloring raw material and the raw material obtained in the comparative example were granulated,
After press molding, it was sintered at 1650°C for 2 hours in the air.

Table 2 shows the results of examining the bending strength and appearance of these samples.

Table 2 (Effects) As explained above, according to the method for producing a colored ceramic raw material according to the present invention, an integral mixture of a base material and a coloring agent is used as a colored ceramic raw material. The indispersibility of the colorant caused by differences in specific gravity and surface conditions can be resolved, and color unevenness does not occur when ceramic products are made, and the strength after sintering is also increased. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the primary coloring step of the present invention, FIG. 2 is a diagram showing the secondary coloring step, and FIG. 3 is a schematic diagram of a colored ceramic raw material. 1... Base material 2... Intermediate raw material Patent applicant Sumitomo Cement Co., Ltd. F, 7. 't-
This agent is patent attorney Kaoru Dobashi. Indication of the case Patent Application No. 141802 of 1988 2, Title of the invention Name of the method for producing colored ceramic raw materials Name (7519) Patent attorney Tsuchibashi Ko Contents of the amendment (1) The "Claims" column of the specification was changed to a separate sheet. Correct as expected. (2) On page 4, line 20 of the specification, the phrase "the fired product is ground using a side mill, etc." is corrected to "the fired product is ground." (3) In the second line of page 5 of the specification, "Rima desu" is corrected to "Rima desu". (4) On page 5, line 3 of the specification: ``In addition, firing and drying''
The statement has been corrected to read, "From firing to drying." (5) In the fourth line from the bottom of page 7 of the specification, the phrase "as a comparison" is corrected to "as a comparative example." Claims: A primary coloring step in which a coloring agent is mixed into a ceramic base material, sintered, and then crushed; and an intermediate material obtained in this primary coloring step is mixed into a ceramic base material, and then sintered and pulverized again. A method for producing a colored ceramic raw material, which comprises a secondary coloring step of obtaining a colored ceramic raw material by pulverization.

Claims (1)

[Claims] A primary coloring step in which a coloring agent is mixed into a ceramic base material, sintered, and then crushed; an intermediate material obtained in this primary coloring step is mixed into a ceramic base material;
A method for producing colored ceramics, which includes a secondary coloring process in which raw materials for colored ceramics are obtained by sintering and pulverizing them again.