Ceramic Materials and Their Properties

There are a variety of different ceramic materials, each with their own capabilities, advantages and disadvantages; their use in bearing and rolling element applications was pioneered by many of the space agencies and continues to be at the forefront of engineering technology.

Ceramic Material 99.5%-AL2O3 SiC HP-Si3N4 GPS-Si3N4 ZrO2- Y2O3
Mechanical Properties Units Metric/Imperial Metric/Imperial Metric/Imperial Metric/Imperial Metric/Imperial
Density g/cm3 (lb/ft3) 3.89(242.8) 3.1 (193.5) 3.29(205.4) 3.27(204) 6.04 (205.4)
Porosity %(%) 0(0) 0 (0) 0(0) 0(0) 0(0)
Color ivory black black black ivory
Flexural Strength MPa (lb/in2x103) 379(55) 550 (80) 830(120.4) 689(100) 900(120.4)
Elastic Modulus GPa (lb/in2x103) 375(54.4) 410 (59.5) 310(45) 310(45) 200(45)
Shear Modulus GPa (lb/in2x106) 152(22)
Bulk Modulus GPa (lb/in2x106) 228(33)
Poisson’s Ratio 0.22(0.22) 0.14 (0.14) 0.27(0.27) 0.24(0.24)
Compressive Strength MPa (lb/in2x103) 2600(377) 3900 (566)
Hardness Kg/mm2 1440 2800 1580 1450 1300
Fracture Toughness KIC MPa•m1/2 4 4.6 6.1 5.7 13
Maximum Use Temperature
(no load)
°C(°F) 1750(3180) 1650 (3000) 1000(1830) 1000(1830) 1500 (2730)
Thermal Units Metric/Imperial Metric/Imperial Metric/Imperial Metric/Imperial Metric/Imperial
Thermal Conductivity W/m°K (BTU•in/ft2•hr•°F) 35(243) 120 (830) 30(208) 29(201) 2 (13.9)
Coefficient of Thermal Expansion 10–6/°C (10–6/°F) 8.4(4.7) 4.0 (2.2) 3.3(1.8) 3.3(1.8) 10.3 (5.7)
Specific Heat J/Kg•°K (Btu/lb•°F) 880(0.21) 750 (0.18)
Electrical Units Metric/Imperial Metric/Imperial Metric/Imperial Metric/Imperial Metric/Imperial
Dielectric Strength ac-kv/mm (volts/mil) 16.9(420) semiconductor semiconductor
Dielectric Constant @ 1 [email protected] 1 MHz 9.8(9.8)
Volume Resistivity ohm•cm >1014 102–106 >1010

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