Silicon nitride sintered body and preparation method thereof

A technology of silicon nitride and sintered body, which is applied in the field of materials, can solve the problems of low temperature, inability to retain the metal state, and the inability to retain the metal state, etc., and achieve the effect of good bending strength

Active Publication Date: 2019-08-13
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, thermodynamic calculations and experiments have shown that metal tungsten, rhenium and silicon nitride ceramics will react chemically when the temperature is higher than about 1400 ° C, while the sintering temperature of silicon nitride ceramics is generally between 1500 ° C and 1900 ° C, resulting in tungsten, rhenium or silicon nitride ceramics. The metal state of its alloy cannot be preserved during sintering, and the material cannot obtain expected properties
Although the sintering temperature of reaction sintered silicon nitride is low, the temperature required for the reaction of residual silicon with metal tungsten or rhenium is lower, and the metal state of tungsten, rhenium or its alloys cannot be retained
Therefore, there is currently no material that incorporates tungsten and / or rhenium as a main component or alloy into a silicon nitride sintered body in the form of discrete particles or discontinuous fibers

Method used

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  • Silicon nitride sintered body and preparation method thereof
  • Silicon nitride sintered body and preparation method thereof
  • Silicon nitride sintered body and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Put 3g of metal tungsten powder with a diameter of 1 μm, 3g of alumina powder, 9g of yttrium oxide powder, and 85g of silicon nitride powder into a silicon nitride ball mill jar, add 150g of absolute ethanol, and 200g of silicon nitride grinding balls;

[0047] Planetary ball mill ball milling for 4 hours, drying in an oven at 80°C for 4 hours, and sieving with 60 mesh to obtain powder raw materials;

[0048] The powder is formed by 10MPa dry pressing and 200MPa cold isostatic pressing;

[0049] The samples were sintered at 1750°C for 2h under 5MPa nitrogen pressure.

[0050] The obtained samples were polished for SEM-EDS micro-area component analysis, X-ray diffraction for chemical state analysis, and ultra-thin slices were prepared for TEM interface and electron diffraction analysis.

Embodiment 2

[0052] 15g of metal tungsten chopped fiber with a diameter of 10μm, 6g of magnesium oxide powder, 5g of ytterbium oxide powder, 2g of silicon oxide powder, and 72g of silicon nitride powder are placed in a silicon nitride ball mill jar, and 120g of absolute ethanol and 200g of nitrogen are added Silicon grinding ball;

[0053] Planetary ball mill ball milling for 8 hours, drying in an oven at 60°C for 6 hours, and sieving with 40 mesh to obtain powder raw materials;

[0054] The powder is formed by direct 250MPa cold isostatic pressing;

[0055] The samples were sintered at 1520°C for 5h under 0.5MPa nitrogen pressure to complete the sintering.

[0056] The obtained samples were polished for SEM-EDS micro-area component analysis, X-ray diffraction for chemical state analysis, and ultra-thin slices were prepared for TEM interface and electron diffraction analysis.

Embodiment 3

[0058] 50g of rod-shaped metal tungsten-rhenium alloy (W-3Re) powder with a diameter of 1μm and a length of 5μm, 3g of alumina powder, 9g of yttrium oxide powder, and 38g of silicon nitride powder were placed in a silicon nitride ball mill jar, and 100g of Water ethanol, 200g silicon nitride grinding ball;

[0059] Planetary ball mill ball milling for 4 hours, drying in an oven at 80°C for 4 hours, and sieving with 80 mesh to obtain powder raw materials;

[0060] The powder is formed by 10MPa dry pressing and 200MPa cold isostatic pressing;

[0061] The samples were sintered at 1760°C for 2 hours under 10MPa nitrogen pressure.

[0062] The obtained samples were polished for SEM-EDS micro-area component analysis, X-ray diffraction for chemical state analysis, and ultra-thin slices were prepared for TEM interface and electron diffraction analysis.

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Abstract

The invention provides a silicon nitride sintered body and a preparation method thereof. The silicon nitride sintered body mainly consists of silicon nitride crystals and a second metal phase dispersed among the silicon nitride crystals, wherein the main components of the second metal phase comprise metal simple substances and/or alloy taking tungsten and/or rhenium as main components. The siliconnitride sintered body has excellent mechanical properties at the normal temperature and the high temperature by introducing the simple substances and/or alloy of tungsten and/or rhenium with the characteristics of non-brittle fracture and high-temperature resistance into silicon nitride.

Description

technical field [0001] The invention provides a metal particle or fiber reinforced silicon nitride sintered body and a preparation method thereof, belonging to the field of materials. Background technique [0002] Silicon nitride ceramics have excellent mechanical properties, high temperature resistance, thermal shock resistance, and corrosion resistance. They are widely used in many fields, but their toughness is still too low compared to metal materials, and their applications are still limited. Tungsten, rhenium and their alloy materials have the characteristics of extremely high melting point, high elongation, excellent mechanical properties, and similar thermal expansion coefficient and elastic modulus to silicon nitride ceramics, making them ideal second phase additives for silicon nitride ceramics. tough material. The simple substance or alloy with tungsten and / or rhenium as the main component is introduced into the silicon nitride sintered body, through their plasti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/584C04B35/622C04B35/645C04B35/80
CPCC04B35/584C04B35/622C04B35/645C04B35/80C04B2235/3206C04B2235/3217C04B2235/3224C04B2235/3225C04B2235/3418C04B2235/40C04B2235/404C04B2235/6586C04B2235/96C04B2235/9607
Inventor 刘学建王鲁杰杨晓张辉姚秀敏黄政仁
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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