JPH06305815A - Production of colored ceramic sintered product - Google Patents

Abstract

(57) [Summary] [Structure] A compound consisting of solid solution powder of cobalt oxide or nickel oxide and oxide white ceramics, oxide white ceramic powder and 10 to 65% by volume of an organic binder is molded and degreased. A method for producing a colored ceramics sintered body, which comprises sintering. [Effect] Even if cobalt oxide or nickel oxide is used as a coloring agent and the compound contains a large amount of the organic binder as described above during molding, coloring is achieved without causing cracking or swelling of the molded product during degreasing. A ceramics sintered body can be manufactured.

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 ceramics sintered body using cobalt oxide or nickel oxide as a coloring agent and using a relatively large amount of an organic binder in a molding step. .

[0002]

2. Description of the Related Art As a method for producing a colored ceramics sintered body, a coloring powder such as alumina, zirconia or the like is mixed with a coloring agent such as cobalt oxide or manganese oxide, sintered and pulverized. Is known, which is mixed with the above white ceramic powder, press-molded, and sintered (JP-A-1-313355).

On the other hand, an injection molding method and an extrusion molding method are known as molding methods suitable for mass-producing a particularly complicated sintered body of fine ceramics such as alumina and zirconia. In this injection molding or extrusion molding, a compound containing a large amount of 25 to 65% by volume of an organic binder is often used.

[0004]

However, not only when the above-mentioned injection molding or extrusion molding is adopted, a large amount of 10 to 65% by volume based on the total amount of the ceramic raw material powder and the organic binder in the compound in the molding process. When an attempt is made to manufacture a ceramics sintered body colored with cobalt oxide or nickel oxide using the organic binder of, the molded body will be cracked or swollen in the step of debinding or degreasing by heating the binder after molding. In the worst case, there is a problem that it is difficult to obtain a product having a desired property and shape because the molded product collapses into powder.

The present invention is to solve such technical problems,
That is, even if cobalt oxide or nickel oxide is used as a colorant and a compound containing a large amount of an organic binder of 10 to 65% by volume based on the total of the ceramic raw material powder and the organic binder is used in the molding step, degreasing is also performed. It is an object of the present invention to provide a method for producing a colored ceramics sintered body, which does not cause cracking or swelling of the molded body in the step of.

[0006]

The present invention includes: a Cobalt oxide or nickel oxide (hereinafter, also referred to as cobalt oxide) and oxide-based white ceramics (hereinafter,
(Also referred to as ceramics) solid solution powder b oxide white ceramic powder (hereinafter also referred to as base material) and c organic binder, and the ratio of the organic binder to the total of the three is 10 to 65% by volume (the present In the specification, a method for producing a colored ceramics sintered body, which comprises molding, degreasing, and sintering a compound in which the proportion (volume%) of the organic binder refers to that at room temperature) It is a thing.

The details of the present invention will be described below.

Powder of a solid solution of cobalt oxide or the like and ceramics can be produced by wet mixing powders of these two components with a ball mill or the like, firing and pulverizing. Although the solid solution limit value for ceramics such as cobalt oxide differs depending on the combination of cobalt oxide and ceramics, for example, by setting the proportion of cobalt oxide or the like in both raw material powders to several tens wt% or less,
It is possible to obtain a solid solution powder containing substantially no solid solution of cobalt oxide or the like.

Examples of the ceramic component in the solid solution powder include alumina, zirconia, and spinel.

The oxide white ceramic powder of the base material is also
Alumina, zirconia, spinel, and the like, and mixtures of two or more thereof may be mentioned, and they may be the same as or different from the ceramic component in the above solid solution.

The total of the solid solution powder and the base, that is, the ratio of cobalt oxide or the like to the ceramic raw material powder is
Although it may be determined depending on the color tone required for the sintered body, it is usually used in the range of 0.1 to 10 wt%. Generally, the amount of solid solution powder is generally smaller than that of the base material, and the production cost of the solid solution powder in the total cost of producing colored ceramics is small. Therefore, the ratio of the solid solution powder to the base is within a range that satisfies other conditions. It can be selected arbitrarily.

The organic binder may be a conventional one, for example, acrylic resin such as polymethylmethacrylate or polybutylmethacrylate; polyethylene, polypropylene, ethylene / vinyl acetate copolymer, ethylene.
Olefin-based resin such as ethyl acrylate copolymer;
Polystyrene; a wide range of thermoplastic resins such as paraffin wax, microcrystalline wax, and waxes such as bees can be used. In addition, the dispersibility of the raw material powder in the organic binder and the fluidity of the compound are improved. For this purpose, lower fatty acids such as stearic acid and higher alcohols such as stearyl alcohol may be added and used.

The solid solution powder, the base material and the organic binder are compounded by first wet mixing the solid solution powder and the base material with a ball mill or the like, and then mixing the mixed powder and the organic binder with a conventional Banbury type heat kneader and heat kneader. It may be carried out by kneading with a kneading machine such as an extrusion granulator which is used for producing general resin products and rubber products.

The compound thus obtained is molded, degreased and sintered by a conventional method to obtain a colored ceramics sintered body.

[0015]

The effects of the present invention are considered to be exhibited by the following mechanism.

That is, even when a ceramic sintered body is manufactured using a raw material powder in which a powder of cobalt oxide or the like is not solid-dissolved and mixed with an oxide-based white ceramic powder, the proportion of the organic binder in the molded body is low and degreasing is performed. If the temperature rising rate is high, the molded body does not crack or swell to the extent of causing a problem in the degreasing process, and the organic binder in the molded body becomes 10% by volume or more, and the cracking or swelling becomes severe enough to be a problem. In the present invention, since the problem of cracking or swelling is solved by using the cobalt oxide or the like as a solid solution in the ceramic powder, the cracking or swelling is caused by the catalytic action of cobalt oxide or the like of the organic binder or the organic binder. This occurs when the decomposition product undergoes an abnormal decomposition reaction, while in a solid solution with oxide white ceramics. It is suppressed catalysis such as the cobalt oxide, thereby no longer occur above cracking and blistering is presumed that the above effect is exhibited.

[0017]

EXAMPLES The present invention will be described in detail below based on examples.

Example 1 Cobalt oxide powder was added to alumina powder having a purity of 99.7 wt% so as to be 20 wt% with respect to the total amount of alumina powder, and wet mixed in a ball mill for 16 hours, and 1100
The mixture was fired at 2 ° C. for 2 hours, wet-milled again in a ball mill for 16 hours, and dried to obtain a solid solution powder. The solid solution powder thus obtained was added to partially stabilized zirconia powder having an yttria content of 3 mol% in an amount of 5 wt% based on the total of the partially stabilized zirconia powder, wet-mixed in a ball mill for 4 hours, and then dried to obtain a raw material. A powder was obtained.

100 parts by weight of the raw material powder thus obtained and an acrylic resin binder (I manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
21 parts by weight of B-27F) was kneaded with a Banbury type mixer at 140 ° C. for 1 hour to obtain a compound for injection molding.

The compound thus obtained was injection-molded by an injection molding machine into pellets having a diameter of 30 mm and a height of 3 mm. The pellets thus obtained are placed under nitrogen in 50
Degreasing was performed by raising the temperature to 0 ° C at 5 ° C / h. Defects such as cracks and swelling did not occur at all in the obtained molded body (hereinafter, the degreased molded body is referred to as a degreased body). Next, this degreased body was fired at 1400 ° C. for 2 hours in the atmosphere to obtain a blue partially stabilized zirconia ceramics sintered body without cracks.

Example 2 Nickel oxide powder was added to spinel powder having a purity of 99.9 wt% so as to be 25 wt% with respect to the total amount of the spinel powder, and wet mixed in a ball mill for 16 hours.
The solid solution powder was obtained by firing at 0 ° C. for 2 hours, wet pulverizing with a ball mill for 16 hours, and drying. The solid solution powder thus obtained was added to a partially stabilized zirconia powder having an yttria content of 3 mol% in an amount of 4 wt% based on the total of the partially stabilized zirconia powder, wet mixed in a ball mill for 4 hours, and dried to obtain a raw material powder. Got

100 parts by weight of the raw material powder thus obtained, 6 parts by weight of ethylene / vinyl acetate copolymer (Ultrasen UE722 manufactured by Tosoh Corporation, the same applies hereinafter), paraffin wax (paraffin wax 135 manufactured by Nippon Seiro Co., Ltd., The same applies hereinafter) and an organic binder consisting of 1.5 parts by weight of stearic acid (a reagent manufactured by Wako Pure Chemical Industries, Ltd., the same applies hereinafter) are kneaded in a Banbury type mixer at 120 ° C. for 1 hour to prepare a compound for injection molding. Then, it was injection-molded by an injection molding machine into pellets having a diameter of 30 mm and a height of 3 mm.

The pellets thus obtained were degreased by raising the temperature to 500 ° C. at 2 ° C./h in the air. Defects such as cracks and swelling did not occur at all in the obtained degreased body. Next, the degreased body was fired at 1400 ° C. for 2 hours in the atmosphere to obtain a green partially stabilized zirconia ceramics sintered body without cracks.

Example 3 Cobalt oxide powder was added to alumina powder having a purity of 99.7 wt% so as to be 25 wt% with respect to the total amount of the alumina powder, and wet mixed in a ball mill for 16 hours, and 1100
The mixture was baked at 0 ° C. for 2 hours, wet-milled again for 16 hours in a ball mill, and dried to obtain a solid solution powder. The solid solution powder thus obtained was added to alumina powder having a purity of 99.7 wt% in an amount of 4 wt% with respect to the total amount of the alumina powder, wet mixed in a ball mill for 4 hours and dried to obtain a raw material powder.

100 parts by weight of the raw material powder thus obtained, 6 parts by weight of an ethylene / vinyl acetate copolymer, 8 parts by weight of paraffin wax and 1.5 parts by weight of stearic acid were added as an organic binder to a Banbury type mixer. Kneading at 120 ° C. for 1 hour to obtain a compound for extrusion molding, and using an extrusion molding machine, diameter 5 mm × height 100 m
m was extruded into a round bar shape.

The round bar thus obtained was placed in nitrogen at 500 ° C.
The temperature was raised at 5 ° C./h until degreasing. Defects such as cracks and swelling did not occur at all in the obtained degreased body. next,
This degreased body was fired at 1650 ° C. for 2 hours in the atmosphere to obtain a blue alumina ceramics sintered body without cracks.

Comparative Example 1 Cobalt oxide powder was added to partially stabilized zirconia powder having a yttria content of 3 mol% so as to be 1 wt% with respect to the total of partially stabilized zirconia powder, and wet mixed for 16 hours with a ball mill, A raw material powder was obtained by drying, and the same conditions as in Example 1 were used.
Kneading with acrylic resin binder for 1 hour at ℃ to obtain compound for injection molding, diameter 30mm with injection molding machine
× Injection-molded into pellets having a height of 3 mm.

The pellets thus obtained are treated with nitrogen in 50
Although the temperature was raised to 0 ° C. at 5 ° C./h and degreasing was performed, the degreased body was disintegrated into powder and the shape of pellets having a diameter of 30 mm and a height of 3 mm was not maintained.

Comparative Example 2 Cobalt oxide powder was added to alumina powder having a purity of 99.7 wt% so as to be 1 wt% with respect to the total amount of the alumina powder, wet mixed in a ball mill for 16 hours, and dried to obtain a raw material powder. Obtained.

The raw material powder thus obtained was treated with a Banbury type mixer under the same conditions as in Example 3 at 120 ° C.
The mixture was kneaded with the organic binder for 1 hour to obtain a compound for injection molding, which was injection-molded by an injection molding machine into pellets having a diameter of 30 mm and a height of 3 mm. The pellets thus obtained were heated in nitrogen to 500 ° C. at 5 ° C./h to degrease them. The resulting degreased body had many cracks.

[0031]

As described above, according to the present invention,
Even if cobalt oxide or nickel oxide is used as a colorant and a large amount of an organic binder of 10 to 65% by volume based on the total amount of the ceramic raw material powder is included in the molding, the molded body is cracked or swollen during degreasing. It is possible to produce a colored ceramics sintered body without causing Therefore, it can be applied very effectively particularly when using a molding method such as injection molding or extrusion molding in which the proportion of the organic binder used must be increased.

Claims (1)

[Claims] 1. A powder of a solid solution of cobalt oxide or nickel oxide and oxide white ceramics, b oxide white ceramic powder and c organic binder, wherein the ratio of the organic binder to the total of the three is 10 to 10. A method for producing a colored ceramics sintered body, which comprises molding a compound of 65% by volume, degreasing and sintering.