JPH0684266B2 - Titanium boride ceramics sintered body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the invention [Industrial field of use] The present invention relates to a titanium boride ceramics sintered body, and more particularly, to a bonding layer formed by solid solution of nickel boride and titanium carbide. The present invention relates to a titanium boride ceramics sintered body in which a matrix layer is arranged between titanium boride particles.

[Prior Art] Conventionally, as a titanium boride ceramics sintered body of this type, a transition metal (for example, chromium Cr) between titanium boride particles is used.
Alternatively, nickel nickel or the like or a transition metal boride (for example, cobalt boride CoB or manganese boride M).
(nB, etc.) have been proposed.

[Problems to be solved] However, in the conventional titanium boride ceramics sintered body, the grain boundary phase formed in the vicinity of the grain boundary of titanium boride TiB ₂ is not continuous, and titanium boride TiB ₂ particles and its Since the reaction between the grain boundary phase (crystal grain boundary phase or glass grain boundary phase) formed near the grain boundary is non-uniform and titanium boride TiB ₂ particles are less likely to grow, titanium boride particles There is a drawback that voids are likely to occur between them, and it is difficult to achieve high density and high strength.

Therefore, in order to eliminate these drawbacks, the present invention provides a high-density and high-strength titanium boride ceramics in which a bonding layer, that is, a matrix layer in which the generation of voids is sufficiently suppressed is arranged between titanium boride particles. The purpose is to provide a sintered body.

(2) Configuration of the Invention [Means for Solving Problems] A means for solving the problems provided by the present invention is that a matrix layer in which nickel boride and titanium carbide are mixed and solid-dissolved is provided between titanium boride particles. Arranged, the titanium boride particles have an average particle size of 0.5 to 8 μm and a maximum particle size of 12 μm or less, and the titanium boride particles are substantially not in contact with adjacent titanium boride particles. It is a titanium oxide ceramics sintered body.

[Operation] In the titanium boride ceramics sintered body according to the present invention, the matrix layer in which nickel boride and titanium carbide are mixed and solid-dissolved is disposed between the titanium boride particles, and the titanium boride particles are Average particle size 0.5-8μm, maximum particle size 12μ
Since it is less than m and is not in contact with the titanium boride particles, it has an effect of sufficiently suppressing the generation of pores in the matrix layer between the titanium boride particles, and thus has an effect of achieving high density and high strength. Eggplant

[Examples] Next, the present invention will be specifically described with reference to the accompanying drawings.

FIG. 1 is an enlarged sectional view showing an embodiment of the titanium boride ceramics sintered body according to the present invention.

FIG. 2 is a copy of an optical microscope photograph showing the texture of the polished outer surface of the embodiment of FIG. 1, showing the case of the embodiment 18.

FIG. 3 is a copy of a scanning electron microscope photograph showing the structure of the fracture surface of the embodiment of FIG. 1, and shows the case of the embodiment 18.

FIG. 4 is a copy of an optical micrograph showing the structure of the etched outer surface of the embodiment of FIG.
Shows the case.

FIG. 5 is a copy of a scanning electron micrograph showing the texture of the outer surface subjected to the etching treatment of the embodiment of FIG. 1 and shows the case of the embodiment 18.

FIG. 6 is a graph showing the results of the X-ray diffraction analysis of the Example of FIG. 1, showing the case of Example 18, in which the X-ray diffraction angle is plotted on the horizontal axis and the vertical axis is plotted on the vertical axis. The X-ray diffraction intensity is taken.

FIG. 7 is a copying diagram of a scanning electron micrograph showing the structure of the fracture surface of the titanium boride ceramics sintered body shown as Comparative Example 1.

First, the structure of an example of the titanium boride ceramics sintered body according to the present invention will be described in detail. 10 is a titanium boride ceramics sintered body of the present invention (hereinafter, also referred to as "ceramics sintered body"),
It has titanium boride TiB ₂ particles 20 and a mesh-like bonding layer 30 for bonding the titanium boride TiB ₂ particles 20.

The titanium boride TiB ₂ particles 20 have an average particle size of 0.5 to 8 μm and a maximum particle size of 12 μm, and particularly an average particle size of 0.5 to 3
It is preferable that the particle size is μm and the maximum particle size is 6 μm. Here, the reason why the average particle size of the titanium boride TiB ₂ particles 20 is 0.5 to 8 μm is that (i) if the average particle size is less than 0.5 μm, the surface oxidation of the titanium boride TiB ₂ particles 20 becomes remarkable, In addition, the agglomeration between the titanium boride TiB ₂ particles 20 becomes remarkable, which significantly inhibits the sintering of the titanium boride ceramics sintered body 10 of the present invention, and (ii) if the average particle diameter exceeds 8 μm. , The driving force for sintering becomes small, making it difficult to densify the titanium boride ceramics sintered body 10 of the present invention, and the existing cracks are enlarged in the titanium boride TiB ₂ particles 20 and the boride of the present invention is formed. The purpose is to reduce the strength of the titanium ceramics sintered body 10 . In addition, the reason why the maximum particle size of titanium boride TiB ₂ particles 20 is 12 μm is that the maximum particle size is 12 μm.
if it exceeds m, it will be present in the titanium boride ceramic sintered body 10 of the present invention as coarse particles, to inhibit densification to high strength titanium boride ceramic sintered body 10 of the present invention is there.

Titanium boride TiB ₂
A grain boundary phase 21 composed of a mixed solid solution phase of TiB ₂ and nickel boride Ni ₃ B is formed. As a result, the bonding force between the titanium boride TiB ₂ particles 20 and the bonding layer 30 is made sufficiently large, and as a result, the strength of the titanium boride ceramics sintered body 10 of the present invention is secured. .

Coupling layer _{30, TiB 2 + 2Ni + C →} 2NiB + TiC or _{TiB 2 + Ni + C → NiB} 2 + TiC or _{TiB 2 + 6Ni + C → 2Ni} 3 boride produced by reactions such as B + TiC between nickel Ni and titanium boride TiB ₂ and carbon C This is a matrix layer in which a metal, that is, boride NiB, NiB ₂ or Ni ₃ B of nickel Ni, and titanium carbide TiC are mixed and solid-solved, and voids are sufficiently removed. This gives titanium boride TiB ₂
The binding force between the particles 20 is sufficiently large, and the relative density of the ceramic sintered body 10 (that is, the value obtained by dividing the volume obtained by subtracting the void volume from the total volume by the total volume) is 95%.
As described above, as a result, the density and strength of the titanium boride ceramics sintered body 10 of the present invention are secured. Here, the reason why the voids are substantially removed from the bonding layer, that is, the matrix layer 30, is that the particle size of boride of nickel Ni, that is, metal boride NiB, NiB ₂ or Ni ₃ B, and the particle size of titanium carbide TiC. And are almost in agreement with each other, and they are in the form of homogeneously mixed and solid solution with each other.

Furthermore, the manufacturing procedure of one embodiment of the titanium boride ceramics sintered body according to the present invention will be described.

In the first step, titanium boride TiB ₂ powder and nickel Ni
The powder and the carbon C powder are blended with each other at an appropriate blending ratio to prepare a ceramic blend.

That is, (i) the average particle size is 0.5 to 8 μm (preferably 0.5
Titanium boride TiB ₂ having a maximum particle size of 12 μm (preferably 6 μm) and a purity of 99% by weight or more, and (ii)
Nickel Ni having an average particle size of 1 to 5 μm (preferably 1 to 3 μm) and a maximum particle size of 12 μm (preferably 6 μm),
(Iii) a specific surface area of 50 to 150 m ² / g (preferably 80~150m ² /
g) with a purity of 99.9% by weight or more and an average particle size of 10 to 100 nm
Carbon (for example, carbon black) C having a maximum particle size of 150 nm (preferably 100 nm) (preferably 10 to 50 nm)
And are blended with each other to form a ceramic blend.
In the ceramic composition, titanium boride TiB ₂ is contained in an amount of 75% by weight with respect to 1 to 25% by weight of a mixture of nickel Ni and carbon C.
Only 99% by weight is included. Also nickel Ni and carbon C
The compounding ratio with is 14: 0.1-10 by weight.

Here, the reason why the purity of titanium boride TiB ₂ is 99% by weight or more is to avoid the adverse effect of impurities during sintering.

The reason why the average particle size of nickel Ni is 1 to 5 μm is that (i) if the average particle size is less than 1 μm, nickel Ni
The surface oxidation of the particles becomes remarkable, and the agglomeration between the nickel Ni particles or the nickel Ni particles and the titanium boride TiB ₂ particles or the carbon C particles becomes remarkable, so that the titanium boride ceramics sintering of the present invention is performed. will be significantly inhibits sintering of the body 10, also (ii) if the average particle diameter exceeds the 5 [mu] m, the matrix layer 30 or titanium boride TiB ₂ particles 20 of titanium boride ceramic sintered body 10 of the present invention the grain Exists as coarse particles in the grain boundary phase 21 formed near the boundary,
This is to reduce the strength of the titanium boride ceramics sintered body 10 of the present invention. The reason why the maximum particle size of nickel Ni is 12 μm is that if the maximum particle size exceeds 12 μm, the existing cracks are expanded in the nickel Ni particles and the strength of the titanium boride ceramics sintered body 10 of the present invention decreases. To be done.

The reason why the average particle size of carbon C is 10 to 100 nm is that (i) if the average particle size is less than 10 nm, the surface oxidation of the carbon C particles becomes remarkable and the aggregation between the carbon C particles becomes remarkable. Therefore, the sintering of the titanium boride ceramics sintered body 10 of the present invention is significantly hindered, and (ii) if the average particle diameter exceeds 100 nm, it is present as coarse particles in the matrix layer 30. The purpose is to reduce the strength of the titanium boride ceramics sintered body 10 of the present invention. The reason why the maximum particle size of carbon C is 150 nm is that if the maximum particle size exceeds 150 nm, the existing cracks in the carbon C particles or titanium carbide TiC particles generated by the reaction with titanium boride TiB ₂ This is to expand existing cracks and reduce the strength of the titanium boride ceramics sintered body 10 of the present invention.

Further grounds for the specific surface area of the carbon C is a 50 to 150 m ² / g is, (i) if the specific surface area is less than 50 m ² / g, titanium boride TiB ₂ become the carbon C particles is too large And (ii) if the specific surface area exceeds 150 m ² / g, the carbon C particles will agglomerate with each other and titanium boride TiB ₂ and nickel Ni The problem is that they cannot mix.

In the second step, the ceramic mixture is homogeneously mixed with an appropriate mixer to prepare a ceramic mixture.

In the third step, the ceramic mixture is put in an appropriate mold together with a binder (for example, polyvinyl alcohol), and then an appropriate pressure (for example, 100 to 800 kg / cm ²
Is applied to uniaxially apply pressure to produce a ceramic green compact.

In the fourth step, the ceramic green compact is subjected to a CIP process, that is, a normal temperature isostatic pressing process by applying an appropriate pressure (for example, a pressure of 800 to 3500 kg / cm ² ), to obtain a ceramic green body.

In the fifth step, the ceramic compact is placed in a non-oxidizing atmosphere (that is, a neutral or reducing atmosphere) such as a vacuum atmosphere (preferably having an atmospheric pressure of 10 ⁻³ Torr or less), an argon atmosphere or a hydrogen gas atmosphere. In a non-pressurized state or a pressurized state (applying a pressure of 100 to 500 kg / cm ² ) at a temperature of 1500 to 2000 ° C (preferably 1600 to 1800 ° C), sintering is performed for an appropriate time, and ceramics sintering is performed. body
Set to 10 . The reason why the atmosphere is a non-oxidizing atmosphere is to prevent titanium Ti, boron B, nickel Ni or carbon C from being oxidized.

As described above, the titanium boride ceramics sintered body 10 according to the present invention is manufactured.

In addition, one embodiment of the titanium boride ceramics sintered body according to the present invention will be described by giving specific numerical values and the like for the purpose of further understanding.

(Examples 1 to 7) Nickel Ni having an average particle size of 1 μm and a specific surface area of 135 m
A mixture of 2.5% by weight prepared by changing the mixing ratio with carbon black C having a purity of 99% by weight at ² / g and an average particle size of 3 μm and a maximum particle size of 6 μm and a purity of 99% by weight. 100 parts of a ceramic compound made by mixing 97.5% by weight of a certain titanium boride TiB ₂ was placed in a plastic container together with urethane balls and 300 parts of ethylene alcohol, and wet mixed for 24 hours. A mixture was made.

The ceramic mixture was kept at a temperature of 60 ° C. for 10 hours to be thoroughly dried. After that, 100 parts of the ceramic mixture
It was housed in an appropriate mold together with 2 parts of polyvinyl alcohol as a binder, and a pressure of 300 kg / cm ² was applied to uniaxially press to obtain a ceramic green compact.

Ceramic green compacts are applied with a pressure of 3000 kg / cm ²
A ceramic compact was obtained by performing P treatment, that is, normal temperature isostatic pressing treatment.

The ceramic compact was heated to a temperature of 1700 ° C. at a rate of temperature increase of 15 ° C./min in an unpressurized argon atmosphere and maintained at a temperature of 1700 ° C. for 1 hour to obtain a ceramic sintered body 10. And

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 1.

(Examples 8 to 14) Mixture of nickel Ni and carbon black C 5.0% by weight
On the other hand, Examples 1 to 7 were repeated except that titanium boride TiB ₂ was blended in only 95% by weight.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 1.

(Examples 15 to 21) 7.5% by weight of a mixture of nickel Ni and carbon black C
In contrast, Examples 1-7 were repeated except that titanium boride TiB ₂ was blended in only 92.5% by weight.

Ceramics sintered body 10 , after polishing the outer surface,
For example, when a photograph of Example 18 (the same applies hereinafter) was observed with an optical microscope, it was as shown in FIG. That is, it was found that the bonding layers 30 were arranged in a dotted manner around the titanium boride particles 20, and the bonding layers 30 were dense with no pores.

The ceramic sintered body 10 was fractured by applying an appropriate force, and the fractured surface was photographically observed with a scanning electron microscope, and it was as shown in FIG. That is, it was found that intragranular fracture occurred in the titanium boride TiB ₂ particles 20, and the titanium boride TiB ₂ particles 20 were strongly bonded by the bonding layer 30. The bonding layer 30 is obtained by X-ray diffraction analysis.
Reaction between titanium boride TiB ₂ and nickel Ni and carbon black C TiB ₂ + 6Ni + C → 2Ni ₃ B + TiC nickel boride Ni ₃ B and titanium carbide Ti
It was found that the matrix layer was a mixed solid solution of C (see FIGS. 4 to 6).

The ceramics sintered body 10 was subjected to an etching treatment on its outer surface by immersing it in aqua regia heated to 60 ° C. for 3 minutes, and then was photographically observed by an optical microscope.
It was as shown in the figure. That is, by binding layer 30 of titanium boride TiB ₂ measures the diameter of the titanium boride TiB ₂ particles 20 caused by falling by etching, the average particle size of the titanium boride TiB ₂ particles 20 within 2~10μm It turned out to be stopped. In other words, titanium boride TiB ₂ particles 20
Was found to have grown less than initially. This is because nickel Ni and carbon black C cause a reaction of TiB ₂ + 6Ni + C → 2Ni ₃ B + TiC during sintering, and the growth of titanium boride TiB ₂ particles 20 is suppressed. Also titanium boride TiB ₂ particles
In the vicinity of 20 grain boundaries, titanium boride was analyzed by X-ray diffraction analysis.
It was also found that a grain boundary phase formed of a mixed solid solution phase of TiB ₂ and nickel boride Ni ₃ B was formed (see FIG. 6).

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 1.

Examples 22 to 28 Mixture of nickel Ni and carbon black C 10.0% by weight
On the other hand, Examples 1 to 7 were repeated except that titanium boride TiB ₂ was blended in an amount of 90.0% by weight.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 1.

(Examples 29 to 35) Mixture of nickel Ni and carbon black C 12.5% by weight
On the other hand, Examples 1 to 7 were repeated except that titanium boride TiB ₂ was blended in only 87.5% by weight.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 1.

(Examples 36 to 42) Mixture of nickel Ni and carbon black C 15.0% by weight
On the other hand, Examples 1 to 7 were repeated except that titanium boride TiB ₂ was blended in an amount of 85.0% by weight.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 1.

(Examples 43 to 49) Mixture of nickel Ni and carbon black C 17.5% by weight
On the other hand, Examples 1 to 7 were repeated except that 82.5% by weight of titanium boride TiB ₂ was blended.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 1.

(Examples 50 to 56) Mixture of nickel Ni and carbon black C 20.0% by weight
On the other hand, Examples 1 to 7 were repeated except that 80.0% by weight of titanium boride TiB ₂ was blended.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 1.

(Examples 57 to 63) Mixture of nickel Ni and carbon black C 22.5% by weight
On the other hand, Examples 1 to 7 were repeated except that titanium boride TiB ₂ was added in an amount of 77.5% by weight.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 1.

(Examples 64-70) Mixture of nickel Ni and carbon black C 25.0% by weight
On the other hand, Examples 1 to 7 were repeated except that titanium boride TiB ₂ was added in an amount of 75.0% by weight.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 1.

(Examples 71 to 77) Mixture of nickel Ni and carbon black C 7.5% by weight
Examples 1 to 7 were repeated, except that 92.5% by weight of titanium boride TiB ₂ was blended and the sintering temperature was 1500 ° C.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 2.

Examples 78-84 Examples 71-77 were repeated except that the sintering temperature was 1600 ° C.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 2.

Examples 85-91 Examples 15-21 were repeated.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 2.

Examples 92-98 Examples 71-77 were repeated except that the sintering temperature was 1800 ° C.

The relative density and the bending strength of the ceramic sintered body 10 were measured and found to be as shown in Table 2.

(Comparative Example 1) From a ceramic composition, nickel Ni and car Examples 1-70 were repeated except that Bonblack C was removed.

That is, 100 parts of titanium boride TiB ₂ having an average particle size of 3 μm, a maximum particle size of 6 μm, and a purity of 99% by weight is accommodated in an appropriate mold together with 2 parts of polyvinyl alcohol as a binder, and 300 kg / cm ² A ceramic green compact was created by applying pressure and uniaxially pressing.

Ceramic green compacts are applied with a pressure of 3000 kg / cm ²
A ceramic compact was obtained by performing P treatment, that is, normal temperature isostatic pressing treatment.

The ceramic compact is heated to a temperature of 1700 ° C. at a temperature rising rate of 15 ° C./min in an unpressurized argon atmosphere and maintained at a temperature of 1700 ° C. for 1 hour to obtain a ceramic sintered body. did.

The ceramic sintered body was fractured by applying an appropriate force, and the fractured surface was photographically observed with a scanning electron microscope, and it was as shown in FIG. 7. Ie titanium boride
It was found that intergranular fracture of TiB ₂ particles occurred predominantly, and the bond between titanium boride TiB ₂ particles was not so strong.

In addition, the relative density and bending strength of the ceramic sintered body were measured, and the results were as shown in Table 1.

Comparative Example 2 Examples 1-7 were repeated except that carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 1.

Comparative Example 3 Examples 8-14 were repeated except that carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 1.

Comparative Example 4 Examples 15-21 were repeated except that carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 1.

Comparative Example 5 Examples 22-28 were repeated except that carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 1.

Comparative Example 6 Examples 29-35 were repeated except that carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 1.

Comparative Example 7 Examples 36-42 were repeated except that the carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 1.

Comparative Example 8 Examples 43-49 were repeated except that carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 1.

Comparative Example 9 Examples 50-56 were repeated except that carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 1.

Comparative Example 10 Examples 57-63 were repeated except that the carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 1.

Comparative Example 11 Examples 64-70 were repeated except that carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 1.

Comparative Example 12 Examples 71-77 were repeated except that nickel Ni and carbon black C were removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 2.

Comparative Example 13 Examples 78-84 were repeated except that nickel Ni and carbon black C were removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 2.

Comparative Example 14 Examples 85-91 were repeated except that nickel Ni and carbon black C were removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 2.

Comparative Example 15 Examples 92-98 were repeated except that nickel Ni and carbon black C were removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 2.

Comparative Example 16 Examples 71-77 were repeated except that the carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 2.

Comparative Example 17 Examples 78-84 were repeated except that carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 2.

Comparative Example 18 Examples 85-91 were repeated except that the carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 2.

Comparative Example 19 Examples 92-98 were repeated except that the carbon black C was removed from the ceramic formulation.

The relative density and bending strength of the ceramics sintered body were measured and found to be as shown in Table 2.

The above Examples 1 to 98 are based on 2.5 to 25% by weight of a mixture of nickel Ni and carbon black C and titanium boride T
iB ₂ is blended in an amount of 75 to 97.5% by weight, and the blending ratio of nickel Ni and carbon black C is 14: 0.2 to 5 by weight.
Was carried out only with respect to the ceramic composition prepared as, but with 75 to 99% by weight of titanium boride and 1 to 25% by weight of the mixture of nickel Ni and carbon black C, and nickel nickel and carbon black C. Good results have also been obtained with a ceramics composition prepared by setting the composition ratio of 14: 0.1 to 10 by weight.

(3) Effects of the Invention As is clear from the above, in the titanium boride ceramics sintered body according to the present invention, the matrix layer in which nickel boride and titanium carbide are mixed and solid-disposed is arranged between the titanium boride particles. However, since the titanium boride particles have an average particle size of 0.5 to 8 μm and a maximum particle size of 12 μm or less, and the titanium boride particles are not in contact with the adjacent titanium boride particles, (I) It has the effect of being able to sufficiently suppress the generation of voids in the matrix layer between titanium boride TiB ₂ particles, and (ii) has the effect of achieving high density and high strength.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing an embodiment of a titanium boride ceramics sintered body according to the present invention, and FIG. 2 is a reproduction of an optical micrograph showing the structure of the outer surface after the polishing treatment of the embodiment of FIG. FIG. 3 is a copy of a scanning electron microscope photograph showing the structure of the fracture surface of the embodiment of FIG. 1, and FIG. 4 is an optical microscope photograph showing the structure of the etched outer surface of the embodiment of FIG. FIG. 5 is a copy diagram of a scanning electron micrograph showing the texture of the outer surface of the embodiment of FIG. 1 which has been subjected to etching treatment, and FIG. 6 is a graph showing the results of the X-ray diffraction analysis of the embodiment of FIG. FIG. 7 and FIG. 7 are copying diagrams of scanning electron micrographs showing the structure of the fracture surface of the titanium boride ceramics sintered body shown as Comparative Example 1. 10 …… Titanium boride ceramics sintered body 20 …… Titanium boride particles 21 …… Grain boundary phase 30 …… Matrix layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hideo Nagashima 30 Soya, Hadano City, Kanagawa Central Research Laboratory, Toshiba Ceramics Co., Ltd. (56) References JP 57-42578 (JP, A) JP 1-172273 (JP, A)

Claims (3)

[Claims] 1. A matrix layer in which nickel boride and titanium carbide are mixed and solid-dissolved is arranged between titanium boride particles, and the titanium boride particles have an average particle size of 0.5 to 8 μm.
A titanium boride ceramics sintered body having a maximum particle size of 12 μm or less, wherein titanium boride particles are not in contact with substantially adjacent titanium boride particles. 2. The titanium boride ceramics sintered body according to claim 1, which has a relative density of 95% or more. 3. The titanium boride ceramics sintered body according to claim 1, which is obtained by sintering in a non-pressurized state.