Method for synthesizing Si3N4 powder body and Si3N4/SiC composite powder body

Abstract

The invention belongs to the field of inorganic non-metallic materials, in particular relates to a method for burning and synthesizing Si3N4 powder and Si3N4 / SiC complex powder in the air. 70-90 parts by weight of silicon powder, 5-30 parts by weight of silicon nitride and 0.5-20 parts by weight of activating agent are mixed to obtain a reactant mixture; grinding activation treatment is carried out to the reactant; an activated reactant is filled into a porous crucible in a loose density of 0.2-1.0g / cm<3>; the porous crucible is placed in the environment of which the air circulation is good to induce the reactant or make the reactant spontaneously do self-spreading burning synthesis reaction, and then the Si3N4 powder is obtained. Under the condition that other technical operations are unchangeable, the Si3N4 / SiC complex powder can be prepared by drawing a C source into the reactant raw materials, and the C source can be carbon black or carboform of which the grain diameter scope is 10-30mm. The method of the invention has the advantages of simple process, convenient operation and low cost.

Description

technical field [0001] The invention belongs to the field of inorganic non-metallic materials, in particular to combustion and synthesis of Si in air 3 N 4 Powder and Si 3 N 4 / SiC composite powder method. Background technique [0002] Si 3 N 4 Ceramics are an important representative of non-oxide ceramic materials. Because of their excellent high strength, high hardness, wear resistance and chemical corrosion resistance, they are widely used in ceramic bearings, ceramic blades, wire drawing dies, rolls, etc. low-cost Si 3 N 4 In recent years, the preparation method of powder has mainly focused on the research direction of self-propagating combustion synthesis (SHS). For combustion synthesis of Si 3 N 4 The process initially required high pressure to obtain a fully reacted product. However, with the continuous development of SHS technology, combustion synthesis of Si 3 N 4 The pressure range used has gradually transitioned from high pressure to low pressure. ...

AI Technical Summary

Problems solved by technology

In 2002, "the method and equipment for low-pressure combustion synthesis of silicon nitride or ferrosilicon nitride" (CN1424249) invented by Sun Jialin of Beijing University of Science and Technology and others was to preheat nitrogen in a vertical combustion synthesis reaction furnace at a preheating temperature of Between normal temperature and 1200°C, control the amount of batching materials added, control the nitrogen pressure at 0.01-3Mpa, and carry out continuous or intermittent combustion synthesis reactions between 900°C and 1850°C, but the preparation process still requires a series of complicated procedures

It is not difficult to see that these synthesis techniques have promoted the Si 3 N 4 The application of powder in industry, but the research towards large-scale and atmospheric pressure is still in progress

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