SOLID STEP PROCESS FOR CONVERTING SOLID POLYCRYSTALLINE ALUMINA BODY TO SAPPHIRE BODY

摘要

PURPOSE: To reduce the cost efficiency by heating a solid polycrystalline alumina body forming a specific surface topography. ;CONSTITUTION: The surface topography 120, which consists of a groove 136 having plural wall surf aces 132 having greater lengths and widths than the average grain size of polycrystalline alumina and being disposed to intersect one another at junctions at angles of 20 to 160° between mutually adjacent wall surfaces 132, is formed on the solid polycrystalline alumina body 100. Then, this polycrystalline alumina body 100 is heated to a temperature above 1500°C and below the melting point of the polycrystalline alumina for a time sufficient to be converted to a body consisting of only sapphire.;COPYRIGHT: (C)1995,JPO