Ceramics are used in many industrial applications, including the automotive industry1. These materials are found in applications for engine parts and engine accessory units, including turbochargers for lower inertia and reduced engine lag and emissions, glow plugs for faster startup, exhaust gas control valves for increased acceleration, and rocker arm pads for gas engines to lower wear2.
Regulatory restrictions on engine emissions and higher fuel costs have driven the use of silicon nitride in the automotive industry3. Each application within the automotive industry requires subtly different, yet tightly controlled attributes, to be able to meet the requirements and attain the greatest improvement in performance versus other materials.
Owing to its excellent thermal shock resistance compared to other ceramics, silicon nitride is a very useful material for the fabrication of high-performance all-ceramic or hybrid steel-ceramic rolling contact bearings4. Due to its extreme strength, toughness, and resistance to chemical and thermal factors, silicon nitride offers significant benefits by extending contact fatigue life.
As a low-density material, silicon nitride can greatly reduce the dynamic loading during ball contacts in very high-speed applications such as those in gas turbine engines.
The material also has notable applications in severe lubrication and wear conditions including extreme temperature, large temperature differential, ultra-high vacuum as well as in safety-critical applications, enabling the material to respond to the specific requirements, i.e. aircraft maintenance operations.
As evidenced by their outstanding performance in extreme environments, silicon nitride bearings are expected to continue to gain wide acceptance in many industrial applications.
4. L. Wanga, R.W. Snidle, L. Gua, “Rolling contact silicon nitride bearing technology: a review of recent research”, Wear, Volume 246, Issues 1–2, November 2000, Pages 159-173