JPH0826819A - Production of compound sintered compact of titanium oxycarbide with aluminum oxide - Google Patents

Abstract

PURPOSE:To obtain a high-density compound sintered compact capable of simply removing embedded alumina powder by carrying out the sandblasting treatment after sintering by using an ultrahigh-purity aluminum oxide powder in a process for embedding a formed compact in the aluminum oxide powder, and sintering the resultant embedded compact under normal pressure. CONSTITUTION:This method for producing a compound sintered compact of titanium oxycarbide and aluminum oxide is to form a homogeneous mixture of 10-60wt.% titanium carbide powder with 90-40 wt.% aluminum oxide powder, embed the resultant formed compact in the aluminum oxide powder and sinter the resultant embedded formed compact at 1700-1900 deg.C under normal pressure in a neutral or a reducing atmosphere. In the process, a high-purity aluminum oxide powder having >=99.9% is used as the embedding raw material.

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 composite sintered body of titanium oxycarbide and aluminum oxide. This composite sintered body is useful as a material for cutting tools and a wear resistant member.

[0002]

2. Description of the Related Art Al ₂ O ₃ has excellent characteristics such as high strength and high hardness, but has a drawback of low toughness. Therefore, by combining TiC, which has high strength, high hardness, and high toughness, TiC-Al ₂ having both advantages.
It is known to use an O ₃ composite sintered body. However, the sintered body is manufactured by the hot pressing method. That is, since TiC, which is one of the components, is difficult to sinter, it is necessary to sinter at a high temperature in order to sinter under normal pressure, and Al ₂ O ₃ evaporates when attempting to sinter at a high temperature. Since it was not obtained as a dense composite sintered body, it was manufactured by the hot pressing method. Therefore, in Japanese Patent Publication No. 5-11062, a homogeneous mixture of 10 to 60% by weight of titanium carbide powder and 90 to 40% by weight of aluminum oxide powder is molded into a green compact,
A compact sintered body of titanium oxycarbide and aluminum oxide, characterized by embedding this green compact in aluminum oxide powder and sintering at 1700 ° C to 1900 ° C under atmospheric pressure in a neutral or reducing atmosphere. In the manufacturing method, Al during sintering
_It is shown that the evaporation of ₂ O ₃ was suppressed and a dense sintered body comparable to the composite sintered body produced by the hot pressing method was obtained.

[0003]

As an embedding raw material powder,
When the relatively inexpensive aluminum oxide powder having a purity of about 99% is used, the embedding powder adheres strongly to the obtained composite sintered body. After sintering, it cannot be removed even by sandblasting, a grinding step is required, and the characteristic of the atmospheric pressure sintering method that machining such as grinding after sintering may be unnecessary is lost. Further, when the embedding material is firmly adhered to the composite sintered body, there is a problem that the density is lowered and sufficient characteristics cannot be obtained. The present invention solves the above problems, and after sintering, the embedded Al ₂ O can be easily processed by sandblasting.
₃ powders can be removed. An object of the present invention is to provide a method for producing a high density composite sintered body.

[0004]

Means for Solving the Problems Titanium carbide powders 10-6
0% by weight and 90-40% by weight of aluminum oxide powder are molded into a homogeneous mixture, the molded body is embedded in aluminum oxide powder, and the temperature is 1700 ° C.
In the method for producing a composite material which is sintered under normal pressure at 900 ° C., it has succeeded in solving the above problems by using a high purity aluminum oxide powder having a purity of 99.9% or more as an embedding raw material.

[0005]

When the aluminum oxide powder having a purity of 99.9% or higher is used as the embedding raw material powder, the embedded aluminum oxide can be easily removed by sandblasting after sintering. Further, the obtained composite sintered body was dense with a theoretical density of 99.9% and a three-point bending strength of 800M.
It exhibited excellent mechanical properties such as Pa and a fracture toughness value of 6.5 MPa√m. On the other hand, when aluminum oxide powder containing impurities such as SiO _{2 of} 0.1% or more is used as the embedding raw material powder, the embedded aluminum oxide partially sinters with the composite sintered body and firmly adheres to it. did. In addition, the density of the obtained composite sintered body was lowered, so that the three-point bending strength and the fracture toughness value were also lowered. The strongly adhered aluminum oxide could not be removed by sandblasting, and needed to be ground by diamond.

[0006]

EXAMPLE An example of the present invention will be described below. 30% by weight of TiC powder having an average particle size of 0.1 μm and an average particle size of 0.2
70% by weight of Al ₂ O ₃ powder having a particle diameter of 0.01 μm and an average particle diameter of 0.01 μm
mOg powder of Mg was mixed homogeneously with 0.2 wt% of Al ₂ O ₃ and press-molded at 5 kg ¹ cm ² to obtain a pump impeller molded body. Average particle size 0.2μ, 0.4
μ, 1.5μ purity 99.99% and 99.9% Al ₂
It was embedded with O ₃ powder and sintered at 1850 ° C. in an Ar stream.
Table 1 shows the removal method of embedded Al ₂ O ₃ , the relative density, the three-point bending strength, and the fracture toughness value of the obtained composite sintered body.

[0007]

[Table 1]

[0008]

Comparative Example A molded body was prepared in the same manner as in Examples 1 and 2, and embedded in Al _{2 O 3} powder having a purity of 99% and 90%.
Sintered at 1850 ° C. in a stream of air. Table 2 shows the removal method of embedded Al ₂ O _{3 in} the obtained composite sintered body, the relative density, the three-point bending strength, and the fracture toughness value.

[0009]

[Table 2]

[0010]

As described above, the effect that the composite sintered body obtained by embedding with the high-purity aluminum oxide powder according to the present invention has no deposit and has high density, high strength and high toughness. Therefore, it can be said that this composite sintered body is very effective in the fields of materials for cutting tools and wear resistant members.

Claims (1)

[Claims] 1. A homogeneous mixture of 10 to 60% by weight of titanium carbide powder and 90 to 40% by weight of aluminum oxide powder is molded, and the molded body is embedded in aluminum oxide powder, and the mixture is neutralized or reduced to 1700. In a method for producing a composite material which is sintered under normal pressure at 1900C to 1900C, characterized in that 99.9% or more of high-purity aluminum oxide powder is used as an embedding raw material, and a composite calcination of titanium oxycarbide and aluminum oxide. A method for producing a bound body.