ceramic ring

Ceramic hermetical rings are the ceramic components or accessories which can prevent the liquid or solid particle from leaking between the combined surfaces,or prevent the outside impurities such as dust or moisture from intruding to the inside of machines or instruments. The products are widely used as the mechanical hermetical components for the industries of metallurgy,mechanism,chemical industry,medication,foodstuff,anti -corrode pumps,motorcar and etc. 95%/99%/99.7% Al2O3 Material Parameters: Item Test Condition Unit&Symbol 95%Alumina ceramics 99%Alumina ceramics 99.7%Alumina ceramics The main chemical ingredient Al2O3 Al2O3 Al2O3 Bulk Density g/cm3 3.6 3.89 3.96 Maximum Use Temperature 1450°C 1600°C 1650°C Water absorption % 0 0 0 ROHS Hardness ≥85 ≥89 ≥89 Flexural strength 20° C MPa (psi x 103) 358 (52) 550 550 Compressive Strength 20° C MPa (psi x 103) 2068 (300) 2600(377) 2600(377) Fracture Toughness K(I c) Mpa m1/2 4-5 5.6 6 Coefficient of thermal expansion 25-1000° C 1X 10-6/°C 7.6 7.9 8.2 Coefficient of thermal conductivity 20° C W/m °K 16 30.0 30.4 Thermal Shock Resistance Tc °C 250 200 200 Dielectricity constant 1MHz.25°C 9 9.7 9.7 Dielectric strength ac-kV/mm (ac V/mil) 8.3 (210) 8.7 (220) 8.7 (220) Volume Resistivity 100°C ohm-cm > 1013 > 1014 > 1014