Qingdao graphite manufacturer explains the difference between silicified graphite and silicon carbide
It is a composite material formed by coating the surface of graphite with silicon carbide. The hardness of silicified graphite is SiC, second only to diamond, boron nitride and boron carbide, and higher than tungsten carbide and aluminum trioxide. Graphite silicified can be used as bearings for pumps such as phosphoric acid, phosphoramide and hydrofluoric acid. In addition, in the semiconductor industry, as a silicon epitaxial growth of the heating substrate and fixtures and the manufacture of artificial joints, artificial heart valves, artificial tooth roots and so on.
It is made from quartz sand, petroleum coke (or coal coke), wood chips (salt is needed in the production of green silicon carbide) and other materials by smelting at high temperature in a resistance furnace. Silicon carbide is also a rare mineral in nature, mulberry stone. Carbonated silicon is also known as carbon silica. Silicon carbide is one of the most widely used and economical non-oxide high tech refractory materials, such as C, N and B. At present, China's industrial production of silicon carbide is divided into black silicon carbide and green silicon carbide, both of which are hexagon crystals with a specific proportion of 3.20 ~ 3.25 and a microhardness of 2840 ~ 3320kg/mm2.
The heat treatment temperature (which reflects the degree of graphitization), thermal expansion coefficient, porosity and pore size distribution of graphite matrix materials have great influence on the process of siliconizing. In order to obtain better properties of silicified graphite, the thermal expansion coefficient of graphite-based materials should be as close as possible to SiC. It is better to use isotropic graphite. The above methods can be combined as required. For example, CVR method and CVD method are adopted to treat the resulting silicified graphite, which is airtight and contains no free silicon. Silica graphite has the characteristics of both carbon and silicon carbide.