Reaction-sintered silicon carbide is an important high-temperature material, with high strength, high hardness, high wear resistance, high corrosion resistance and high oxidation resistance and other excellent properties, is widely used in machinery, aerospace, chemical industry, energy and other fields.
1. Raw material preparation
The preparation of reactive sintering silicon carbide raw materials are mainly carbon and silicon powder, of which carbon can be used a variety of carbon-containing substances, such as coal coke, graphite, charcoal, etc., silicon powder is usually selected with a particle size of 1-5μm high purity silicon powder. First, carbon and silicon powder are mixed in a certain proportion, adding an appropriate amount of binder and flow agent, and stirring evenly. The mixture is then put into a ball mill for ball milling to further uniform mixing and grinding until the particle size is less than 1μm.
2. Molding process
Molding process is one of the key steps in silicon carbide manufacturing. Commonly used molding processes are pressing molding, grouting molding and static molding. Press forming means that the mixture is put into the mold and formed by mechanical pressure. Grouting molding refers to mixing the mixture with water or organic solvent, injecting it into the mold through a syringe under vacuum conditions, and forming the finished product after standing. Static pressure molding refers to the mixture into the mold, under the protection of vacuum or atmosphere for static pressure molding, usually at a pressure of 20-30MPa.
3. Sintering process
Sintering is a key step in the manufacturing process of reaction-sintered silicon carbide. Sintering temperature, sintering time, sintering atmosphere and other factors will affect the performance of reaction-sintered silicon carbide. Generally, the sintering temperature of reactive sintering silicon carbide is between 2000-2400℃, the sintering time is generally 1-3 hours, and the sintering atmosphere is usually inert, such as argon, nitrogen, and so on. During sintering, the mixture will undergo a chemical reaction to form silicon carbide crystals. At the same time, carbon will also react with gases in the atmosphere to produce gases such as CO and CO2, which will affect the density and properties of silicon carbide. Therefore, maintaining a suitable sintering atmosphere and sintering time is very important for the manufacture of reaction-sintered silicon carbide.
4. Post-treatment process
Reaction-sintered silicon carbide requires a post-treatment process after manufacturing. Common post-treatment processes are machining, grinding, polishing, oxidation and so on. These processes are designed to improve the precision and surface quality of reaction-sintered silicon carbide. Among them, the grinding and polishing process is a common processing method, which can improve the finish and flatness of the silicon carbide surface. Oxidation process can form an oxide layer to enhance the oxidation resistance and chemical stability of reaction-sintered silicon carbide.
In short, reactive sintering silicon carbide manufacturing is a complex process, need to master a variety of technologies and processes, including raw material preparation, molding process, sintering process and post-treatment process. Only by comprehensively mastering these technologies and processes can high quality reaction-sintered silicon carbide materials be produced to meet the needs of various application fields.
Post time: Jul-06-2023