Preparation method of silicon nitride powder

A technology of silicon nitride powder and silicon powder is applied in the field of preparation of silicon nitride powder, which can solve the problems of difficult production management, many processes, and many equipment, and achieves long preheating time, reasonable connection relationship and high thermal power. Effect

Active Publication Date: 2018-09-21
ZHEJIANG YUYAO NEW MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0015] 4. Difficult production management: many equipment, large workshop, many links, many processes, large investment
[0016] 5. Many supporting facilities: auxiliary facilities such as dust absorption, anti-static, vibration isolation, and noise reduction

Method used

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  • Preparation method of silicon nitride powder
  • Preparation method of silicon nitride powder
  • Preparation method of silicon nitride powder

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preparation example Construction

[0111] A preparation method of silicon nitride powder, comprising the following steps:

[0112] 1) Equipment preheating: heat the coil in the microwave plasma preheater and the inner chamber of the suspension reactor to 800-850°C and 1350-1400°C respectively with a microwave plasma torch.

[0113] 2) Material heating: Silicon powder (purity 99.99%, feed rate 1.2-1.8g / s, particle size 0.8-1.2vm), ammonia gas (purity 99.999%, flow rate 0.5-1cm 3 / s), nitrogen (purity 99.999%, flow 18-22cm 3 / s) The mixture is passed into the coil of the microwave plasma preheater for mixing and preheating to 700-750°C. The residence time of the mixture of silicon powder and ammonia and nitrogen in the coil is 50-60 seconds. Then the material is passed into the heating zone of the suspension reactor inner chamber in the form of upward spraying to form an inverted conical aerosol to continue heating; simultaneously, an upward nitrogen vortex flow is passed into the heating zone (flow rate is 10-...

Embodiment 1

[0118] A preparation method of silicon nitride powder, comprising the following steps:

[0119] 1) Equipment preheating: Heat the coil in the microwave plasma preheater and the inner cavity of the suspension reactor to about 825°C and 1375°C respectively with a microwave plasma torch.

[0120] 2) Material heating: silicon powder (purity 99.99%, feeding about 1.5g / s, particle size about 1vm) and ammonia gas (purity 99.999%, flow rate 0.75cm 3 / s), nitrogen (purity 99.999%, flow rate 20cm 3 / s) into the coil of the microwave plasma preheater for mixing and preheating to about 725°C. The residence time of the mixture of silicon powder and ammonia and nitrogen in the coil is about 55 seconds. Then the material is passed into the heating zone of the inner chamber of the suspension reactor in the form of upward spraying to form an inverted conical aerosol to continue heating; 3 / s or so, the pressure is maintained at 1.45-1.5 kPa) to drive the material to rotate. The residence t...

Embodiment 2

[0138] A preparation method of silicon nitride powder, comprising the following steps:

[0139] 1) Equipment preheating: Heat the coil in the microwave plasma preheater and the inner cavity of the suspension reactor to about 800°C and 1350°C respectively with a microwave plasma torch.

[0140] 2) Material heating: silicon powder (purity 99.99%, feed rate 1.8g / s, particle size about 0.8vm) and ammonia gas (purity 99.999%, flow rate 0.5cm 3 / s), nitrogen (purity 99.999%, flow rate 18cm 3 / s) into the coil of the microwave plasma preheater for mixing and preheating to about 700°C. The residence time of the mixture of silicon powder and ammonia and nitrogen in the coil is about 50 seconds. Then the material is passed into the heating zone of the suspension reactor inner chamber in the form of upward spraying to form an inverted conical aerosol to continue heating; simultaneously, an upward nitrogen vortex flow is passed into the heating zone (flow rate is 10cm 3 / s or so, the p...

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Abstract

The invention relates to the field of silicon nitride preparation and discloses a preparation method of silicon nitride powder. The preparation method comprises the steps: 1) equipment preheating, 2)material heating: putting a mixture of silicon powder and ammonia, and nitrogen in a coil of a microwave plasma preheater for mixing and preheating to 700-750 DEG C, putting the materials in a heatingarea of an inner cavity of a suspension reactor for heating continuously, and supplying an upward nitrogen vortex flow into the heating area to drive the materials to rotate, 3) reaction: dropping the materials to a reaction area, supplying the upward nitrogen vortex flow into the reaction area to drive the materials to rotate for reaction to generate silicon nitride during dropping, 4) heat insulation and cooling: allowing silicon nitride and unreacted nitrogen to enter a heat insulation cooler, cooling the materials through water cooling, then through water cooling and air cooling, and finally through water cooling, and 5) gas-powder separation. The silicon nitride powder prepared according to the method is high in purity, small in particle size and high in yield and is produced quickly, and an alpha phase content is high.

Description

technical field [0001] The invention relates to the field of silicon nitride preparation, in particular to a method for preparing silicon nitride powder. Background technique [0002] Silicon nitride is an important structural ceramic material. It is a superhard substance, inherently lubricious, and wear-resistant, and is an atomic crystal; it resists oxidation at high temperatures. Moreover, it can also resist cold and heat shocks, and it will not shatter when heated to above 1000°C in the air, cooled rapidly and heated again sharply. It is precisely because silicon nitride ceramics have such excellent characteristics that people often use it to manufacture mechanical components such as bearings, gas turbine blades, mechanical seal rings, and permanent molds. [0003] At present, domestic silicon nitride powder production mainly consists of the following two methods: [0004] 1. Bell furnace electric or microwave heating nitrogen infiltration method [0005] Steps: sili...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/068C04B35/584
CPCC01B21/0682C04B35/584
Inventor 任小平
Owner ZHEJIANG YUYAO NEW MATERIAL CO LTD
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