Silicon carbide is the ideal sealing material. It has the property of excellent resistant-corrosion, high mechanical strength, high thermal conductivity, good self-lubrication, used as seal faces, bearings and tubes in spacecraft, machinery, metallurgy, printing and dyeing, foodstuff, auto industry and so on. When the sic faces are combined with graphite faces, the friction is the smallest and they can be made into mechanical seals which are able to work in highest working requirements.
SiC physical property
Technical Parameter Unit SiC SSiC SiC+C/SSiC+C
Purity % >90 >97 30%carbon
Free Si % ≤12 ≤1 ≤1
Density g/cm3 >3.05 3.03-3.15 2.65
Hardness HS 115-125(HS) >92(HRA) ≥85(HS)
Grain size um 8~20 0.5~0.7 20~40
Elastic Modulus GPa 420 400 -
Compressive Strength MPa 3000 3900 1800
Fractured Strength MPa 400 450 >380
Coefficient of Heat Expansion 10-6/oC 4.3 4.5 3
Thermal conductivity (Wm/k) 35~110 125.6 125
Poisson ratio 0.15 0.14 -
Temperature oC 1300 1650 800