Silicon Nitrideis an electrical insulator and is a dry nonferrous alloy. It is a quite expensive material. However, its performance to cost benefit ratio is outstanding in the applications wherever it can do better than the normally utilized materials with long life and very consistent low maintenance operation. Silicon nitride (Si3N4) is a non oxide ceramic having brilliant mechanical/thermal features. It has two main types’ alpha and beta, the alpha type is mostly used as powder materials, and the beta type is used as fillers to enhance wear, thermal/resistance conductivity of resins, etc. It is a fine powder whose average particle size varies from submicron order to crude granule powder. Main types of Si3N4 materials: RBSN (Reaction bonded silicon nitride) SSN (Sintered Silicon Nitrides) GPS- SSN (Gas Pressured Sintered Silicon Nitrides) HPSN (High pressured Sintered Silicon Nitride) Reaction bonded Si3N4 is prepared by direct nitridation of a compressed silicon powder, and because of the complexity of ensuring whole reaction, it’s hard to attain a very high constituent density. Standard densities ranges from 2.4 – 2.6g/cm3 compared with up to 3.4g/cm3 for high pressured sintered silicon nitride and gas. The higher density provides the GPS-SSN, HPSN and SSN materials improved resources and physical properties. They are used in more challenging applications at very high wearing temperature. This includes chemical resistance, electrical insulating properties, corrosion resistance and high temperature particularly for non ferrous molten metal parts. The nitridation of Si3N4 generates very small volume change. This means that RBSN components do not need to be machined after manufacturing. Machining Silicon Nitride is a very intricate process which is used to produce net shapes in a single process stage. HPSN, GPS-SSN and SSN can contract for complete densification without any porosity. They also have very strong and solid arrangement for difficult applications in a variety of high tech industrial applications. Properties of Silicon Nitride High thermal shock resistance Low density High temperature, strength and capability Outstanding chemical and wear resistance Good electrical insulating properties and fracture toughness Exceptional compressive strength and creep resistance High Mechanical fatigue Brilliant non wetting property with good oxidation resistance Some important applications of Si3N4: Automotive: Turbocharge Rotors, Tappet Shims, Bearings & Buckets, Cam Rollers, Squeeze Rollers, High pressured pumps parts, Rocker arm tips, welding location pins, for radiator tube production etc. for its better mechanical dependability, wear and corrosion resistance. Bearings & Balls: Completely dense different size balls from 0.6mm up to 55mm OD, entirely intense ceramic Roller Bearing, Bearing, Tapper & Plain Bearings for 50% lighter weight, 60% higher speed, chemical resistance, electrical- magnetic insulating, high temperature etc. Also Hybrid bearing having rollers & ceramic Balls for high strength. Gas & Oil Industries: Needles, compression Rings, sleeves, plungers, seals etc. are used for the harsh surroundings which produces wear, chemical, corrosion and high temperature challenges that can be met through the use of dense Si3N4 Defence & Nuclear: This advanced ceramic are used as a were resistance tiles, impact plates, discs, ring etc. due to hard wear, lightweight, and toughness. Electronics & Electrical: A large variety of high performance parts are created for the electrical and electronic industry due to non-magnetic and insulating properties. Various parts include microwave specialty ceramics and wafer processing components etc. --------------------- I'm working in Ceramics industry from many years. I have a great knowledge in machining silicon nitride. My writings are beneficial for increasing awareness of the not so popular but important Ceramic industry. If anyone have comments or suggestions on this post please feel free to let me know. Thanks
