Silicon nitride-based or SiAlON ceramics are increasingly being considered for many engineering applications due to their low density, high strength, and high modulus. For many engineering applications SiAlON ceramics are required to have, among many other properties, both high fracture toughness and good tribological properties. Typically, an interlocking microstructure consisted of β-Si3N4 and/or β'-SiAlON grains is produced, by sintering Si3N4 with desirable additive(s), with a residual glassy or partly crystalline grain boundary phase. The fracture process in such a microstructure is predominantly intergranular, the cracks tend to follow a tortuous path. However, the presence of an intergranular glassy phase causes rapid deterioration of properties at temperature above the glass transition temperature. Therefore, in order to improve high-temperature properties of these ceramics it is desirable to minimize, and if possible to eliminate, the intergranular glassy phase. Particle coating techniques are receiving increasing attention as they are convenient ways of incorporating sintering aids/dopants more uniformly than conventional powder blending method.