Method for manufacturing transparent polycrystalline aluminum oxynitride

Abstract

The present invention relates to a method of manufacturing a transparent polycrystalline aluminum oxynitride. Aluminum oxynitride manufactured by prior art methods has a great number of porosities therein and thus has low transparency. The present invention is directed to solving such a problem. In the method of manufacturing aluminum oxynitride of the present invention, a sintering additive added to a source powder includes less than 0.5 wt. % MgO. Further, the source powder is presintered at 1550° C. to 1750° C. so that a relative density becomes 95% or more and is then resintered at 1900° C. or more so that a relative density higher than that of presintering can be accomplished. According to the present invention, a cubic-phased polycrystalline aluminum oxynitride ceramic can be obtained, wherein porosities therein are nearly eliminated and its substantial transparency becomes 95% or more.

Dependencies are inferred from the claim text.