Material Silicon nitride
Silicon nitride (Si3N4) is light, hard, and has low thermal expansion coefficent. It has high mechanical strength, fracture toughness, and it is resistant to deformation at room temperature as well as at elevated temperatures.

Si3N4 differs from other ceramics because it doesn't melt, but, between 1800 and 1900 C, it decomposes and sublimates into Si and N. However, stabilised forms can be made.

The most common applications are for engine parts (valves, pistons, etc.), energy plants (gas turbines, diesel engines etc.), and ultra high-temperature applications. Particulary important is its corrosion resistance (jigs and tools).
Danish Name Siliciumnitrid
Products Ceramic bearing balls
Motor valve, ceramic
Solar cell
Turbine rotor
Processes Powder technology
References Atlantic Equipment Engineers
H.C. Starck GmbH & Co. KG
Johnson Matthey GmbH
Price Silicon nitride powder (technical grade, 98% purity) costs about 160 DKK/kg. Depending on the quantities and the grade purchased, prices can be higher (up to 1400 DKK/kg for 99.8% purity, small amounts).
Additional Info Colour: dark grey;
Max. use temperature: 1500C;
E-modulus: 427 GPa;
Thermal conductivity: 27 W/mK.
Copyright © 1996, 97, 98 Torben Lenau