Generally, Al2O3 ceramic means ceramic that with α-Al2O3 as the main crystalline phase, and content of Al2O3 is between 75%~99.9%. Customarily, as a commodity, Al2O3 is named according to the nominal content, for instance, #99 ceramic means nominal content of Al2O3 is 99%, and #95 ceramic means nominal content of Al2O3 is 95%. For ceramic that Al2O3 content is higher than 85%, it’s called high alumina ceramic, if higher than 99%, then called corundum ceramic. During all ceramics, Al2O3 has the largest consumption. According to statistics of Japan in 1981, Al2O3 occupies 35.1% of all ceramic products. Al2O3 has various of application on basis of content and structure, and the main application as follows:

1.With high hardness and strength, Al2O3 ceramic has good machinability, abrasiveness and abrasive resistance, so it’s important material for tool, mould, clock bearing, grinding wheel and ball, mud pump piston, etc.

2.With good electric insulativity, it’s the most widely used insulative ceramic (mounting ceramic), often used for IC packaging, substrate, piston, shell of vacuum switch, stem of magnetron. Since lattice constant of sapphire (Al2O3) is closed to that of silicon, it’s usually used as substrate for SOS （Silicon on Sapphire）of monocrystal silicon epitaxial growth.

3.With good heat resistance, it’s often used for furnace products, such as crucible, furnace tube, furnace chamber, etc., also widely used as common material of refractory products like firebrick, refractory fiber, etc.

4.With good corrosion-resistance performance, it’s common material for chemical products and parts of anti-acid pump. Furthermore, Al2O3 has light transmittance, can be used as tube of sodium lamp and infrared window; with laser oscillation, can be used as ruby oscillator; with biocompatibility, it can be used for artificial bone and teeth root. β-Al2O3 is used as material of sodium-sulphur battery septum for its ionic conductance; for Al2O3 cement, the main content is Al2O3-CaO, with performance of rapid hardening and large heat release, it’s widely used as building material for winter construction or urgent engineering job.