Reaction system for synthesizing silicon nitride powder

Abstract

The invention relates to the field of silicon nitride preparation, and discloses a reaction system for synthesizing silicon nitride powder. The reaction system comprises a microwave plasma preheater,a suspension reactor and a heat insulation cooler, wherein the suspension reactor comprises a furnace tube, a furnace case, a heating torch and a spray pipe; an inner cavity of the furnace pipe is divided into a heating region and a reaction region; the upper end of the furnace pipe is fixedly provided with the heating torch; the lower end of the furnace pipe is provided with a discharging opening; the furnace case is sleeved outside the furnace pipe; heat insulation cotton is arranged between the furnace pipe and the furnace case; the spray pipe penetrates through the furnace case and the furnace pipe to enter the heating region of the inner cavity of the furnace pipe; in addition, a spray nozzle is arranged at the tail end of the spray pipe; a nitrogen gas inlet is formed in the furnacecase; a circle of air inlet seam is arranged at the same height on the inner wall of the furnace pipe; the air inlet seam is provided with an opening in the vertical direction and is in an inclined upward direction towards the inner cavity of the furnace pipe; the air inlet seam is provided with an opening in the horizontal plane, is approximately or completely tangent with the curve surface of the inner wall of the furnace pipe; in addition, the facing directions of all openings are identical. The silicon nitride powder prepared by the reaction system has the advantages of high purity, fine particle diameter, high alpha phase content, high yield and fast production.

Description

technical field [0001] The invention relates to the field of silicon nitride preparation, in particular to a reaction system for synthesizing 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]...

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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

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