Aluminum oxide based sintered body

An aluminum oxide based sintered body produced by firing a powder mixture comprising silicon carbide, said silicon carbide being in the form of particles generally round, which comprises:

• i) silicon compounds in an amount of from about 5 to about 40 mole %, calculated as a carbide,
• wherein said silicon compounds comprise unreacted silicon carbide and silicon-containing glass, said silicon-containing glass being present alone grain boundaries;
• ii) at least one metal or metal compound of from about 0.5 to about 25 mole %, calculated as metals, selected from Ti, Nb, Tb, Ta, Cr and Mo,
• wherein said at least one metal or metal compound comprises metal carbide;
• and
• iii) the remainder of Al.sub.2 O.sub.3,
• wherein the molar ratio of the at least one metal with respect to said silicon compounds, calculated as a carbide, is about 4 or less, and
• wherein the at least one metal carbide has an average particle size of about 1 .mu.m or less and is dispersed in the aluminum oxide based sintered body.