Silica carbide crucibles are made from silicon carbide, which is made by reacting silica and carbon at high temperatures. This creates a compound with the chemical formula SiC, which is extremely hard and has excellent chemical and thermal resistance properties.
The silicon carbide crucibles are used for high-heat metallurgical processes like dissolve, alloying and casting metals. These extreme heat aren’t compatible with regular ceramic or graphite crucibles.
Carbon bonded silicon carbide crucibles and sintered silicon carbide crucibles are two ways to make silicon carbide crucibles. Carbon bonded silicon carbide crucibles are made by mixing SiC grains with a resin binder, shaping them into crucible shapes, and curing them at high degrees. They can withstand 1800°C. SiC crucibles without a binder are made by press molding SiC powder and firing it to make a hard, ceramic crucible.
Silicon carbide crucibles are resistant to chemical corrosion and oxidation, so they’re great for melting metals like aluminum, copper, nickel, and other alloys. They’re also good for casting metals in large quantities because they’re resistant to chemical attack by fluxes.
However, silicon carbide crucibles can react with and dissolve in molten metals like aluminum at high degrees, which can contaminate the metal and shorten their life. They’re also brittle and expensive, so they’re not good for everything. In most high heat metallurgical applications, silicon carbide crucibles provide excellent thermal shock resistance, strength, and chemical stability.