JPS63222071A - Electroconductive zro2 base sintered body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a conductive ZrO2-based sintered body that has good conductivity, can be subjected to electrical discharge machining, and has high strength.

[Conventional technology]

ZrO2-based sintered bodies are widely known as having toughness among ceramics, and their uses are expanding, regardless of whether they are used for other purposes such as cutlery or for industrial purposes.

However, there are still some problems in further expanding its use. Among them, the problem of workability is raised. This is because the advantages of ZrO2-based sintered bodies, such as high strength and high hardness, mean that good workability cannot be obtained. This is especially a big problem when applied to complex shapes.

On the other hand, electric discharge machining has recently achieved rapid progress in the field of machining high hardness materials such as cemented carbide.

In the field of ceramics, including ZrO2-based sintered bodies, research on conductive ceramics that can be subjected to electrical discharge machining is progressing.

Conventionally, ZrO2-based sintered bodies considered to have electrical conductivity include: (1) ZrO2-C, which is produced by firing a mixed powder compact consisting of chromium metal powder and zirconia powder in a nitrogen gas atmosphere;
r2N (Japanese Unexamined Patent Publication No. 61-236653), ■ NbC powder (average particle diameter) in psz powder (average particle diameter 0.5 μm)
,,27zm) was added to 20-35 vol%, mixed, and then sintered in a hot press to produce a Zr07-NbC sintered body (
Proceedings of the 1986 Ceramics Association Annual Meeting P3], 9)
has been reported.

The present inventor has conducted various studies based on the above-mentioned prior art, etc., and has found that it is practically desirable to further improve electrical discharge machinability and have high strength.

That is, an object of the present invention is to provide a conductive ZrO2-based sintered body that has good conductivity and high strength.

[Means for solving problems]

In view of the above problems, the present invention was developed as a result of various studies on nitride-added ZrO2-based sintered bodies that are thought to be capable of pressureless sintering.
When TjN and ZrN are added to ZrO as nitrides and sintered, they have good conductivity and are easily densified, and the average particle size of the conductive phase in the sintered body is 2.
This is based on the discovery that when the thickness is .mu.m or less, it contributes to improvement in conductivity and strength.

That is, the present invention provides one or both of TiN and ZrN.
The seeds are composed of ZrO2 with a tetragonal crystal structure, with the remainder being composed of ZrO2 with a tetragonal crystal structure, TiN and Zr
This is a conductive ZrO2-based sintered body characterized in that the average particle size of the conductive phase composed of one or two types of N is 2 μm or less, and the electrical resistance is 10 −2 Ω·zheng or less. Furthermore, temperature 1300-1600℃, pressure 50at
It has been found that by applying hot isostatic pressing under conditions of 0 or more, the porosity becomes O and the strength is dramatically improved.

In order to obtain the sintered body of the present invention, TjN, ZrN and
After pulverizing ZrO containing stabilizers such as Y2O3
, and then sintered in a nitrogen atmosphere at a temperature in the range of 1400 to 1600°C. In order to further improve the strength, the temperature is 1300 to 1600℃ and the pressure is 50℃.
By applying hot isostatic pressing under ATM conditions,
The porosity is 0 and the bending strength is 130 to 160 kg.
/ mm2.

In the present invention, in order to obtain ZrO2 having a mainly tetragonal crystal structure, a conventionally known stabilizer such as Y2O3, JOlCe, 0, etc. is contained. In addition, the term "tetragonal product" mainly refers to the following two cases, including lJi diagonal product and cubic crystal structure.

The content of TiN and ZrN is 20 vol. If it is less than 60 vol %, the electric resistance will be 10 -2 Ω·■ or more, and electrical discharge machining cannot be performed, and if it exceeds 60 vol %, the strength will be significantly reduced. Therefore, it was limited to 20 to 60 vo]%.

In addition, the reason why the average particle size of the conductive phase composed of one or two of Tj, N, and ZrN is set to 2 μm or less is because the conductivity is within this range, as is clear from the examples described later. This is because it has been found that both strength is improved.

〔Example〕

The present invention will be explained in more detail below based on examples.

Example 1 Commercially available N powder, 0.2 μm [Hakusui Kagaku Co., Ltd.],
TiN powders having particle sizes of 2 μm (Nu Metals Co., Ltd.) and 5 μm (Nu Metals Co., Ltd.) were prepared.

These powders were added in an amount of 30 vol % to a commercially available ZrO 2 powder containing 3 mol % of Y 2 O 3 produced by a coprecipitation method, and mixed in a ball mill. A binder is added to this, granulated with a spray dryer, and the granulated powder is filled into a rubber mold to make 3 tons.
Molded on/ci. After the molded body was degreased, it was sintered at 1500° C. under N21 atmosphere in an atmospheric furnace. After sintering, 1
Hot isostatic pressing was performed at 450°C, 11,000 at, and N2 atmosphere to produce sintered bodies containing TiN with various particle sizes. Table 1 shows the average particle size, electrical resistance, and bending strength of TjN in the obtained sintered body.

The bending strength was measured according to JIS R1601 (the same applies hereinafter).

From Table 1, it can be seen that when the average particle size of T 3-N is 1.8 μm or less, both the electrical resistance and the bending strength are improved.

Example 2 Commercially available ZrN [average particle size 3 μm, Nu Metals Co., Ltd.]
] The powder is crushed in a Gen 1 mill, classified, and has a maximum particle size of 1.
TjN powders with three types of particle sizes of 2.5 μm were prepared.

7. Using these powders, various particle sizes were prepared under the same conditions as in Example 1. A sintered body containing rN was created.

Table 2 shows the average particle size, electrical resistance, and bending strength of ZrN in the obtained sintered body.

From Table 2, it can be seen that when the average particle size of ZrN is 1.6 μm or less, both the electrical resistance and the bending strength are improved.

Example 3 TiN and ZrN powders having a particle size of 2 μm or less were prepared,
It was added in a range of 10 to 70 vol% to Zr○2 powder produced by a coprecipitation method containing 3 mo1"1 of commercially available Y2O3 and mixed in a ball mill. After adding a binder and making a slurry, it was made with a spray dryer. It was granulated, filled with the granulated powder in a rubber mold, and molded at 3 tons/cA.After degreasing, it was sintered in an atmospheric furnace at 1500°C under N2] pressure.

After sintering, HIP treatment was performed at 1450° C. and 11000 atm in a Nzn atmosphere. Figures 1 and 2 show measurements of the electrical resistance and bending strength of the sintered body after HIP. The bending strength was measured according to JISRl, 601.

From this, when TiN or ZrN is 25 vol % or more, the electrical resistance becomes 10 −2 Ω·■ or less. In addition, when the bending strength exceeds 60vo]%]OOkg/r
It can be seen that trn12 or less.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a conductive Z r OZ-based sintered body having good conductivity and excellent strength, which is very useful industrially.

[Brief explanation of the drawing]

Figure 1 shows the T i when using raw material powder of 2 μm or less.
A graph showing the relationship between N content, electrical resistance, and bending strength, Figure 2 shows ZrN when raw material powder of 2 μm or less is used.
2 is a graph showing the relationship between the content, electrical resistance, and bending strength. TiN addition amount (VO2) ZrN addition amount (vol%)

Claims (1)

[Claims] 1. 20 to 60 of one or both of TiN and ZrN
vol%, the remainder mainly Zr having a tetragonal crystal structure
The average particle diameter of the conductive phase composed of O_2 and one or both of TiN and ZrN is 2.
A conductive ZrO_2-based sintered body characterized by having an electrical resistance of 10^-^2 Ω·cm or less. 2 Hot isostatic pressing is performed at a temperature of 1300 to 1600°C and a pressure of 50 atm or more, and the bending strength is 100K.
The conductive ZrO_2-based sintered body according to claim 1, characterized in that the conductive ZrO_2-based sintered body has a conductive conductivity of at least g/cm^2.