ZrO2-containing glass-ceramic

摘要

A glass-ceramic contg. ZrO2 has a ZrO2 crystal phase and at least one further crystal phase, and contains (in wt.%) 42.5-58.5 SiO2, 0-7.0 Al2O3, 0-9.5 La2O3, 7.0-14.5 Li2O, 0-7.5 Na2O, 0-135 K2O, 4.0-13.5 P2O5, 15.0-28.0 ZrO2, 0-6.0 TiO2, 0-2.0 P, 0-6.5 BaO, 0-6.0 CaO, 0-3.3 B2O3, and 0-3.0 CeO2. Pref. amts. are: 47-55% SiO2, 0-5% Al2O3, 7-14% Ki2O, 0-6% Na2O, 0-8% K2O, 5-11% P2O5, 16-25% ZrO2 and 0-1.5% P. The ZrO2 crystal phase contains ZrO2 in the tetragonal modification and a further crystal phase is formed by a SiO2 crystal modification and/or a SiO2 isotype AlPO4 modification, or may be formed by Li phosphate. Prepn. of the glass-ceramic involves: (a) prepn. of a glass contg. the claimed components, and (b) subjecting the glass to a heat treatment to form the glass-ceramic. A shaped article may be formed by casting the molten glass or by sintering granulated glass, followed by (b) heating this by pressing in the viscous state at 850-1200 (850-1100) degrees C, opt. followed by further heating at 580-1100 degrees C. A shaped dental prod. contg. the ceramic is claimed.