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Preparation method of silicon nitride high-temperature ceramic material in multistage twin structure

A technology of high-temperature ceramics and silicon nitride, which is applied in the field of preparation of multi-level twinned silicon nitride high-temperature ceramic materials, can solve the problems of performance weakening and grain growth, so as to improve fluidity, inhibit grain growth, Accelerated densification effect

Active Publication Date: 2019-04-23
SHAANXI SCI TECH UNIV
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Problems solved by technology

[0003] The present invention aims at the present situation in the field of research and development where common means are difficult to solve the problem of performance weakening due to grain growth, and provides a method for preparing a multi-level twinned silicon nitride high-temperature ceramic material

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  • Preparation method of silicon nitride high-temperature ceramic material in multistage twin structure

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preparation example Construction

[0018] A method for preparing a multi-level twin structure silicon nitride high-temperature ceramic material of the present invention comprises the following steps:

[0019] (1) Using three-dimensional eddy current resonance ball mill equipment to perform high-frequency impact treatment on silicon powder, the spindle speed is 150-300 rpm, the vibration frequency is 6-12 Hz, and then synthesized in a nitrogen atmosphere high-temperature tube furnace with a nitrogen flow rate of 100 ~240ml / min, synthetic temperature 1520~1590℃, heat preservation 100~120 minutes, heating and cooling rate 4~6℃ / min, to obtain nano-silicon nitride powder;

[0020] (2) Add glue to the nano-silicon nitride powder and centrifugally spheroidize it. The spheroidized glue is 35mol / L polyvinyl butyral alcohol solution, and the mass ratio of powder to glue is (86.3~94.3):(5.7~13.7), degreased Finally, it is formed in a two-way heavy pressing device, the degreasing temperature is 500-530°C, and the cold form...

Embodiment 1

[0024] (1) Using three-dimensional eddy current resonance ball mill equipment to carry out high-frequency impact treatment on elemental silicon powder, the spindle speed is 150 rpm, the vibration frequency is 6 Hz, and then synthesized in a nitrogen atmosphere high-temperature tube furnace, and the nitrogen flow rate is 240 ml / min. The synthesis temperature is 1520°C, the temperature is kept for 100 minutes, and the heating and cooling rate is 5°C / min to obtain nano-silicon nitride powder;

[0025] (2) Add glue to the nano-silicon nitride powder and centrifugally spheroidize it. The spheroidized glue is 35mol / L polyvinyl butyral alcohol solution, and the mass ratio of powder to glue is 87:13. After degreasing, it is molded in a two-way heavy pressure device , the degreasing temperature is 500°C, and the cold pressing pressure is 280MPa to obtain a polycrystalline silicon nitride green body;

[0026] (3) The molded body was placed in a four-way overpressure heat collector for u...

Embodiment 2

[0028] (1) Using three-dimensional eddy current resonance ball mill equipment to carry out high-frequency impact treatment on elemental silicon powder, the spindle speed is 170 rpm, the vibration frequency is 7 Hz, and then synthesized in a nitrogen atmosphere high-temperature tube furnace, and the nitrogen flow rate is 120 ml / min. The synthesis temperature is 1530°C, the temperature is kept for 100 minutes, and the heating and cooling rate is 5°C / min to obtain nano-silicon nitride powder;

[0029] (2) Add glue to the nano-silicon nitride powder and centrifugally spheroidize it. The spheroidized glue is 35mol / L polyvinyl butyral alcohol solution, and the mass ratio of powder to glue is 88:12. After degreasing, it is molded in a two-way heavy pressure device , the degreasing temperature is 520°C, and the cold pressing pressure is 250MPa to obtain a polycrystalline silicon nitride green body;

[0030] (3) The molded body was placed in a four-way overpressure heat collector for u...

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Abstract

The invention discloses a preparation method of a silicon nitride high-temperature ceramic material in a multistage twin structure. The method comprises processing monatomic silicon powder at high impulse, subjecting the processed monatomic silicon powder to reaction with nitrogen to obtain silicon nitride nanopowder, adding in gel for nodulizing and degreasing shaping to obtain a cold pressing blank, and sintering the shaped cold pressing blank at ultrahigh pressure and high temperature to obtain the silicon nitride high-temperature ceramic material in the multistage twin structure. The preparation method of the silicon nitride high-temperature ceramic material in the multistage twin structure is high in composition control precision, technical stability and repeatability and capable of achieving high-temperature toughening of silicon nitride ceramic materials.

Description

technical field [0001] The invention relates to the technical field of high-temperature ceramic preparation, in particular to a method for preparing a multi-level twinned silicon nitride high-temperature ceramic material. Background technique [0002] Silicon nitride ceramic is a high-temperature structural ceramic material, and high-temperature strength and toughness are one of the most important indicators restricting its application in high-temperature fields. Silicon nitride ceramics are mainly prepared by the traditional powder low-pressure sintering method, and the high firing temperature (>1500°C) causes the grains to grow seriously. Inhibition is limited. Therefore, it is very important to find a new method to refine the grains of silicon nitride ceramics and improve its high temperature strength and toughness. Contents of the invention [0003] The present invention aims at the present situation in the research and development field where it is difficult to s...

Claims

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Application Information

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IPC IPC(8): C04B35/584C04B35/626C04B35/65C04B35/645
CPCC04B35/591C04B35/593C04B35/62645C04B35/645C04B35/65C04B2235/96
Inventor 艾桃桃董洪峰李文虎
Owner SHAANXI SCI TECH UNIV
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