Silicon nitride porous ceramic composition and preparation method thereof

Abstract

The invention discloses a porous silicon nitride ceramics composing prescription and a method for the products thereof, containing the following components by weight: 50-70 per centsilicon nitride powder, 5-30 per cent bentonite, 0-10 per cent sintering additives and 20-30 per cent water. The sintering additives, contain at least one of Y2O3, Al2O3 and MgO and the method includes: weighing the components except water before placing into a ball mill for dry mixing-grinding to make a mixed powder which is then put into a wheel roller for wheel grinding and kneading to obtain a pug; putting the pug into an extruder for extrusion forming to obtain a shaped body; then drying the shaped body before putting into an atmosphere oven where the shaped body is heated to a temperature of 1700-1850 DEG C in the nitrogen at a heating rate of 10 DEG C / min and then insulation sintered for 1 to 3 hours at a nitrogen pressure of 1-6 atmospheric pressure to obtain a sintered body . The porous silicon nitride ceramics of the invention can be widely used as matrix of filters for gas separation at high temperature and in corrosive atmosphere and as heat-resistant or enhanced materials for power generation gas turbines, engines and space shuttles.

Description

technical field [0001] The invention relates to a porous ceramic and a preparation method thereof, in particular to a prescription and a preparation method of a silicon nitride porous ceramic. Background technique [0002] Due to the existence of rod-shaped particles in its microstructure, silicon nitride porous ceramics have good heat resistance, corrosion resistance, high strength, high toughness, etc., and are suitable for gas separation filters in high temperature atmospheres or corrosive atmospheres Or its substrate, and the reinforcement phase of metal matrix composites have been widely used. According to the different starting powders used, the existing preparation methods of silicon nitride porous ceramic materials are as follows: [0003] 1) Atmosphere sintering method, using silicon nitride particles or amorphous raw materials, heating the molded body in nitrogen to form a porous ceramic with a uniform fibrous silicon nitride-based structure, such as the productio...

AI Technical Summary

Problems solved by technology

The debinding process presents some serious problems

First, the debinding process is very time-consuming, especially for large-sized products, which often takes several days, resulting in a decrease in production efficiency

Second, the improper heating system in the degumming process can easily cause defects such as cracks in the green body

The large release of carbon dioxide can easily lead to the greenhouse effect, while hydrocarbon gases are very smelly and even poisonous, which are not good for the environment

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