Patent ID: 7510607

Claim:
A coating composition comprising a binder, a solvent, and an Î±-alumina powder, wherein the Î±-alumina powder satisfies the following (a) and (b): (a) when the Î±-alumina powder is pressed to obtain a green body and the green body is sintered at 1250Â° C. under atmospheric pressure, the sintered body has a relative density of about 80% or more, and (b) a BET specific surface area of the Î±-alumina powder is about 10 m 2 /g; and wherein the Î±-alumina powder is obtained by calcining an Î±-alumina precursor in an atmosphere of a partial pressure of water vapor of about 600 Pa or less, and wherein silicon, iron, titanium, sodium and calcium are each contained in the Î±-alumina precursor in an amount of about 50 ppm or less.