Silicon nitride powder is a grey powder (Moh's hardness 8.5) which is an important structural ceramic material. It is super-hard, inherently lubricious, and resistant to wear and tear. It is also an atomic crystal; it resists oxidation at high temperatures and has excellent thermal shock resistance.

Production of si3n4 powder is accomplished by one of three methods: direct nitridation, the reaction of SiCl4 and NH3, or carbothermal reduction of SiO2. These are versatile, inexpensive techniques that produce Si3N4 in powder form with high hardness, melting point, and chemical resistance.

A low-temperature nitriding process, using diluted HF at 1400 to 1500 deg C, produces Si3N4 in powder form with high purity and strength. This nitriding process is the most common method used for producing silicon nitride in industrial quantities.

The highest-temperature nitriding process, which produces a highly crystalline and pure form of Si3N4 in a single step, uses hot gas at 2000 to 3000 deg C. This nitriding process has been used to develop materials for aerospace applications, including components for satellites and specialized fuel cells.

It has also been used in manufacturing mechanical components such as bearings, turbine blades, mechanical seal rings and permanent molds. The lubricity of silicon nitride helps reduce friction. Moreover, it is highly resistant to wear and tear and can be molded with precision into various shapes. It is an important choice for many different applications that need superior toughness and strength.

tags: Semiconductors semiconductor industry