Translucent polycrystalline alumina and process for producing the same

摘要

Translucent polycrystalline alumina made of aluminum oxide containing magnesium oxide in an amount of larger than 0.01% by weight and less than 0.03% by weight, zirconium oxide in an amount of larger than 0.01% by weight and less than 0.06% by weight and calcium oxide in an amount of less than 0.001% by weight, all based on the weight of aluminum oxide, which alumina has good light transmittance and mechanical strength.