JPS62143874A - Manufacture of non-oxide 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 Field of Industrial Application The present invention relates to a method for manufacturing a non-oxide sintered body used as a cemented carbide tool or a high-temperature structural material.

Conventionally, non-oxide sintered bodies are made by mixing metal oxides with non-metal element powder or solid non-metal elements and reacting them at high temperatures. It was produced by thoroughly pulverizing and sintering it under high temperature and pressure. This method requires a long (complicated) manufacturing process, is prone to contamination with impurities, and consumes a large amount of energy. Methods for producing sintered bodies have been proposed (e.g., B.D. Zapitsanos and J.R. Morris).

Junior Ceramic Engineering Society. Proceedings (P, mouth, Zavitsano
sand J, R, Morris, Jr, , C
eram, Eng, Sci, l'r.

c, ), 4. [7-81, G24 (1983)), this method involves thoroughly mixing powders of metal and nonmetallic elements (carbon and boron), molding them, and igniting a part of the molded product under pressure to cause a reaction. This is a method in which the synthesis of non-oxides and the creation of a sintered body are performed simultaneously (referred to as a pressurized self-combustion sintering method).

While the invention is trying to solve the problem: Suspension point The sintered body created by this method requires an ultra-high pressure of 3 GPa, and the relative density (density of the sintered body/theoretical density) is 95%. Furthermore, mechanical properties such as hardness were slightly lower than sintered bodies made by conventional methods.

Journal of the American Ceramic Society (Y, Miyamoto, M, Koizu
mi and O, Yamada, J, Am, C
eram, Soc, ), 67, No, 11.
Means for Solving the Problems of C-224 The feature of the present invention is that a linear metal is used as a metal raw material when producing a non-oxide sintered body by a pressure self-combustion sintering method.

According to the present invention, a high-density sintered body can be easily obtained by the pressurized self-combustion sintering method, so the sintered body is similar to or even higher than that of a conventional sintered body made using non-oxide powder. A non-oxide sintered body having mechanical strength can be produced with extremely low energy consumption.

Examples Example 1 Using linear niobium with a wire diameter of 25 μm and a length of 0.2 mm and carbon black with a particle size of 0.1 μm or less as starting materials, both were weighed out at a molar ratio of 1:1, and dissolved in hexane. After wet mixing and drying in a vacuum dryer, the diameter is 10 mm and the height is 10 m.
It was press-molded into a columnar shape of m. This molded body was subjected to pressure self-combustion sintering using a uniaxial pressure vacuum hot press using a mold made of silicon carbide rice. The molded body was ignited by energizing the tungsten filament. The sample was placed at 500℃, vacuum (10-'mm!Ig) atmosphere, O,
Under a pressure condition of 1 GPa, the ignition heater was energized to start the reaction.

When the obtained sintered body was identified using X-ray diffraction, only the diffraction line of niobium carbide was observed. Also, the relative density of this sintered body is 98.7L? It was 6. The structure of the sintered body consisted of uniform elongated grains, and the length of the longer axis was about 100 μm and the length of the shorter axis was about 30 μm. The length of the shorter shaft was approximately the same size as the wire diameter of the niobium starting material.

The Vickers hardness of the sample is 22 GN/ at a load of 500g.
It was a. This value was the same as the hardness of a sintered body produced by a conventional method.

Example 2 A linear niobium-titanium alloy with a wire diameter of 25 μm and a length of 0.2 mm and carbon black with a particle size of 0.1 μm or less were used as starting materials, and both were weighed out at a molar ratio of 1:1. A molded article was produced under the same conditions as in Example 1. This molded body was subjected to pressure self-combustion sintering using a uniaxial pressure vacuum pot press using a mold made of silicon carbide rice. The molded body was ignited by energizing the tungsten filament.

The sample was placed under the conditions of 300°C, vacuum (10-'a++nl1g) atmosphere, and pressure of O, 1GPa, and the ignition heater was energized to start the reaction.

When the obtained sintered body was identified using X-ray diffraction, no diffraction lines of niobium carbide and titanium carbide were observed. Furthermore, from the shift in the peak position of this powder XL9 pattern, it was confirmed that niobium carbide and titanium carbide were each significantly dissolved in solid solution with each other.

Moreover, the relative density of this sintered body was 99.2%. The structure of the sintered body consisted of elongated grains, with the length of the longer axis being 80 μm and the length of the shorter axis being 10 μm. The length of this shorter axis was quite small compared to the wire diameter of the starting niobium-titanium alloy with j≦11.

The Vickers hardness of the sample is 20 ON/ under a load of 500g.
It was i.

Example 3 A linear mole having a wire diameter of 35 μIn with a ratio of mo/2.1. A sintered body of molybdenum carbide was prepared in the same manner as in Example 1 using Nobdenum and the same NoJ-bon black as in Example 1. However, after heating to 1200° C. under an argon atmosphere, the mixture was heated in a vacuum state (1o-3) for 4 times. Further, the pressurizing force was 0.01 G Pa.

When the obtained sintered body was identified using X-ray diffraction, only the diffraction line of molybdenum carbide was observed. Moreover, the relative density of this sintered body was 98%. The structure of the sintered body was composed of elongated grains as in Examples 1 and 2. The length of the longer axis was 150 μm, and the length of the shorter axis was 30 μm, which were about the same as the wire diameter of the starting material molybdenum.

The Vickers hardness of the sample is 14 ON at a load of 500g.
It was 10r.

Example 4 Linear niobium and pan-based carbon fibers (diameter 1
A sintered body of niobium carbide (7 μm, length 20.2 mm) and the same carbon black as in Example 1 was prepared in the same manner as in Example 1. However, under an argon atmosphere,
After heating to 700°C, vacuum B (10-3 m m I
t g ), 0. It ignited under pressure of IGPa.

When the obtained sintered body was identified using X-ray diffraction, only the diffraction line of niobium carbide was observed. Further, the relative density of this sintered body was 99%. The structure of the sintered body was composed of elongated grains as in Example 1. The length of the longer axis of this grain is 1100I1, and the length of the shorter axis is 30μm, and the length of the shorter axis is about the same as the wire diameter of the starting material niobium. there were.

The Vickers hardness of the sample is 25 GN/ at a load of 500 g.
n(was.

Example 5 Linear titanium (diameter: l) in a molar ratio of 1:1:2.

A sintered body of titanium carbide was prepared in the same manner as in Example 1 using titanium powder having a particle size of 0 μm (1 length: 0.1 mm) and a particle size of 40 μm or less, and carbon black having a particle size of 0.1 μm or less. However, after heating to 500°C in an argon atmosphere, the heating was performed in a vacuum state (10-3 mmHg) at 0.05°C. I
It ignited under pressure of GPa.

When the obtained sintered body was identified using X-ray diffraction, no diffraction lines of titanium carbide were observed. Further, the relative density of this sintered body was 99%. The structure of the sintered body was different from Example 1 and consisted of isotropic grains and elongated grains. The particle diameter of the isotropic grains was 30 μm, the length of the long axis of the elongated grains was 100 μm, and the length of the short axis was 50 μm.

The Vickers hardness of the sample is 28 GN/ under a load of 500g.
/Met.

Example 6 A sintered body of niobium boride was produced in the same manner as in Example 1 using the same linear niobium as in Example 1 and amorphous boron with a particle size of 0.1 μm or less in a molar ratio of 1:2. Created. However, after heating to 200°C in an argon atmosphere, at that temperature, in a vacuum state (10-3 + nmt 1g), 0
．． It ignited under pressure of IG Pa.

When the obtained sintered body was identified using X-ray diffraction, only the diffraction line of niobium boride was observed.

Moreover, the relative density of this sintered body was 98%. The structure of the sintered body was composed of elongated grains as in Example 1. The length of the long axis of these grains was 70 μm, and the length of the short axis was 10 μm, which was considerably smaller than the wire diameter of the starting material niobium. .

The bitsnose hardness of the sample is 24 O at load m: 500 g.
It was N/nf.

Example 7 Linear titanium with a molar ratio of 1.14 (diameter: 1.00μ+
A sintered body of titanium boride was prepared in the same manner as in Example 1 using titanium powder with a particle size of 40 μm or less and amorphous boron with a particle size of 0.1 μm or less. However, room temperature, vacuum condition (10-”mm It
g), ignited under pressure of O, 1, GPa.

When the obtained sintered body was identified using X-ray diffraction, only the diffraction line of titanium boride was observed.

Moreover, the relative density of this sintered body was 98%. The structure of the sintered body was similar to that of Example 1, and consisted of isotropic grains and elongated grains. And the particle size of the isotropic grain is about 8μ]1
1, the length of the long axis of the elongated grain is 40 μin, and the length of the short axis is 5 μm.

The bitsnorth hardness of the sample is 27 GN at a load of 500g.
/n? Met.

Effects of the Invention According to the manufacturing method of the present invention, while pressure is applied to a molded body of a mixture of a linear metal and a non-oxide element, a part of the molded body is ignited under high heat to cause a combustion reaction. A non-oxide sintered body can be produced by simply allowing it to rise. Therefore, according to the production method of the present invention, a non-oxide sintered body can be produced with a much lower temperature process, that is, with extremely less energy, compared to the conventional production method using non-oxide powder. Moreover, the obtained sintered body has properties that are the same or better than those of the sintered body produced by the conventional manufacturing method.

Claims (2)

[Claims] (1) A compact made of a linear metal and a nonmetallic element is ignited under pressure to start a combustion process, and the heat generated as a result of the combustion process causes a reaction between the metal and the nonmetallic element. and a method for producing a non-oxide sintered body, which proceeds with sintering of the generated non-oxide. (2) A non-oxide sintered body according to claim 1, characterized in that the combustion process is started under conditions in which a molded body made of a linear metal and a nonmetallic element is pressurized and heated. manufacturing method.