Patent ID: 7297171
Filing Date: 2007-11-20
Classification: B24D,C03C,C09K

Abstract:
1. A method for making a glass-ceramic, the method comprising heat-treating glass to convert at least a portion of the glass to crystalline ceramic and provide glass-ceramic, the glass comprising at least 50 percent by weight Al 2 O 3 , based on the total weight of the glass, REO, ZrO 2 , and at least one of Nb 2 O 5 or Ta 2 O 5 , wherein the glass contains not more than 10 percent by weight collectively As 2 O 3 , B 2 O 3 , GeO 2 , P 2 O 5 , SiO 2 , TeO 2 , and V 2 O 5 , based on the total weight of the glass, and wherein the at least one of Nb 2 O 5 or Ta 2 O 5 is present in an amount sufficient to increase the rate of crystalline ZrO 2 formation from the glass as compared to a comparative glass-ceramic made by heat-treating, in the same manner, the same glass free of Nb 2 O 5 and Ta 2 O 5 .