Method for preparing high-temperature resistant silicon carbide

Abstract

The invention relates to a method for preparing high-temperature resistant silicon carbide. The method is technically characterized by comprising the following steps of: uniformly mixing liquid polycarbosilane and organic metal salt, crosslinking and curing, performing ball-milling, cracking at the temperature of between 900 and 1,100 DEG C, and performing high-heat treatment at the temperature of between 1,600 and 1,850 DEG C to obtain the crystalline silicon carbide containing a trace amount of metal elements. A SiO2 protection membrane which is obtained by performing high-temperature oxidation on the synthesized silicon carbide is SiO2 solid solution containing a trace amount of metal elements. The trace amount of metal elements reduces the activity of SiO2, and increases the conversion temperature of active and passive oxidation of the silicon carbide, so that the use temperature of the silicon carbide is increased. Compared with the prior art, the method has the advantages that: by introducing a trace amount of metal elements into the silicon carbide, the use temperature of the silicon carbide is increased from 1,700 to 1,800-1,850 DEG C, and equipment used by the preparationprocess is simple, safe and reliable, is easy to control and contributes to large-scale production.

Description

technical field

[0001] The invention relates to the field of ceramic materials, in particular to a method for preparing high-temperature-resistant silicon carbide. Background technique

[0002] Silicon carbide (SiC) ceramics have excellent properties such as small thermal expansion coefficient, high decomposition temperature, low density, high high-temperature strength, corrosion resistance, wear resistance, and ablation resistance, and are the most promising high-temperature structural materials used above 1300 °C One of them, widely used in heat-resistant, wear-resistant and harsh environments.

[0003] Oxidation occurs when SiC ceramics are used at high temperatures, and the oxidation mechanism is divided into active oxidation and passive oxidation. Active oxidation occurs at high temperature and low oxygen partial pressure, and SiC material is oxidized to generate volatilized SiO, resulting in a reduction in material quality and subsequent material failure. Passive oxi...

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