Silicon nitride is a man made compound synthesized through several different chemical reaction methods. Parts are pressed and sintered by well developed methods to produce a ceramic with a unique set of outstanding properties. The material is dark gray to black in color and can be polished to a very smooth reflective surface, giving parts with a striking appearance. High performance silicon nitride materials were developed for automotive engine wear parts, such as valves and cam followers and proven effective. The cost of the ceramic parts never dropped enough to make the ceramics feasible in engines and turbochargers. The very high quality bodies developed for these demanding high reliability applications are available today and can be used in many severe mechanical, thermal and wear applications.
Key Silicon Nitride Properties
High strength over a wide range of temperatures
Highly resistant to fractures
High hardness
Superior wear resistance, both impingement and modes that are frictional
Good resistance to shock
Good chemical resistance
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Typical Silicon Nitride Uses
Turbine blades, vanes, buckets
Metal tube forming rolls and dies
Precision shafts and axles in high wear environments
Weld positioners
Rotating bearing balls and rollers
Cutting tools
Engine moving parts — valves, turbocharger rotors
Engine wear parts — cam followers, tappet shims
General Silicon Nitride Information
The material is an insulator that is electric is not wet by nonferrous alloys. Silicon nitride is really a rather expensive material, but it’s performance to cost benefit ratio is excellent in the applications where it can outperform the normally utilized materials with long life and very reliable maintenance operation that is low.
Silicon nitride ceramics material composition
Aluminum (Al) 2.0~3.5%
Yttrium (Y) 4.0~5.0%
Titanium (Ti) 1.0~1.5%
Oxygen (O) 4.5~6.0%
Carbon（C） 0.3~0.8%
Other impurities is less than 0.1%
The rest are Nitrogen and Silicon
Density g/cm3 ≥3.20
Hardness Hv 1400~1600
Three point flexural strength Mpa >800
Compression strength Mpa >4000
The elastic modulus Gpa 300~315
Fracture toughness Mpa.m1/2 6~8
The coefficient of thermal expansion 10 -6/℃ 2.2~3.0
Maximum working temperature ℃ 800
Color Black Technology CIP+GPS