Silicon nitride (Si 3N4) shows an excellent combination of material characteristics. Even its weight is nearly as low as silicon carbide (SiC), it has, because of its structural conditions, a very high resistance against temperature cycling and is stabil against mechanical crashes and shocks. That is the result of its high fracture toughness.
The structural conditions are composed of bacillary crystals, interlocked like micro rods. A very popular application is chipping gray iron or cast iron by ceramic cutting inserts. In opposite to carbide and other cutting materials the operations can be executed by top speed and without any cooling lubricant. The combination of good tribological characteristics and high fracture toughness predestines silicon nitride ceramic as balls in very light and precise ceramic sleeves. A wide Field of application is in the automotive industries.