Casting-molded large-scale nitride-combined silicon carbide product

Abstract

The invention relates to a casting-molded large-scale nitride-combined silicon carbide product. The product employs silicon carbide particles and powder, silicon carbide micro powder, silicon dioxide micro powder, alumina micro powder, active magnesium oxide and a water reducer as powder materials, employs silica sol as a binder and is molded by employing vibration casting. A molded blank is subjected to maintenance, drying, and high-temperature nitridation processing in nitrogent, so that the nitride-combined silicon carbide product is prepared. By reacting silicon dioxide and silicon carbide in the materials with nitrogen at the conditions of high temperature and nitrogen, silicon nitride is generated and other nitrides are further generated, and thus the combination strength is generated. The products helps to solve the problems and the disadvantages that conventional nitride-combined silicon carbide products generated through nitridation of silicon powder is high in cost and relatively easily have residual silicon, large-scale products cannot be produced, and the like. According to the technical scheme, the large-scale nitride-combined silicon carbide product can be produced and has the advantages of low cost, excellent performances and the like, the prepared silicon carbide product is capable of replacing conventional Si3N4-combined, Si2N2O-combined and Sialon-combined silicon carbide and being applied to fields of steel industry blast furnace air ports and blast furnace cooling wall cast-in bricks, nonferrous metals industry aluminium electrolytic tanks and the like.

Description

Technical field [0001] The invention belongs to the technical field of inorganic non-metallic materials. Specifically, it relates to a cast-molded large-scale nitride bonded silicon carbide product, which can solve the existing problems and deficiencies in the formation of nitrides from silicon powder, and can prepare large-scale nitride bonded silicon carbide products, and the prepared silicon carbide products can replace existing Si 3 N 4 , Si 2 N 2 O and Sialon combined with silicon carbide are used in blast furnace tuyere and blast furnace cooling wall inlay in the steel industry, and aluminum electrolytic cells in the non-ferrous industry. Background technique [0002] Nitride bonded silicon carbide products are based on Si 3 N 4 , Si 2 N 2 O, Sialon and AlN and other single-phase or multiple-phase nitrides are high-grade silicon carbide refractory materials with the combined phase. It inherits many excellent properties of nitride and silicon carbide materials, and has high ...

AI Technical Summary

Problems solved by technology

Nitriding of silicon powder is an exothermic reaction, and a slight improper control of the nitriding process will easily lead to excessive local temperature, which will cause the silicon powder to melt and block the pores

The above two effects make the nitriding inside the product very difficult

Therefore, the process control requirements for producing nitride-bonded silicon carbide materials by in-situ nitriding of silicon powder are relatively high, and it is difficult to complete nitriding when the size and thickness are above 250mm, and residual silicon is prone to appear and affect product performance.

The above shortcomings make the existing silicon powder in-situ nitriding process unable to prepare larger-sized nitride-bonded silicon carbide products