New thermally crystallizable glasses and low expansion transparent translucent and opaque ceramics made therefrom

Abstract

Abstract THE PRESENT PATENT APPLICATION DISCLOSES COMPOSITIONS OF MATTER IN THE FORM OF GLASSES COMPOSED MAINLY OF SILICA AND ALUMINA ANC CONTAINING OTHER ESSENTIAL INGREDIENTS. THE GLASSES OF THE INVENTION ARE QUITE REFRACTORY AND THERMAL SHOCK RESISTANT, HAVING ANNEALING POINT TEMPERATURES OF AT LEAST 1100*F. AND COEFFICIENTS OF THERMAL EXPANSION IN THE RANGE 30 TO 50X10-7/*C. OVER THE RANGE ZERO TO 300*C.; THEY ALSO HAVE LIQUIDUS TEMPERATURES OF LESS THAN 2550*F. THE REFRACTORY GLASSES CAN BE FORMED IN THE USUAL WAYS BY PRESSING, BLOWING, ETC., TO MAKE A VARIETY OF USEFUL ARTICLES SUCH AS TABLEWARE AND OVENWARE. OTHER ESSENTIAL INGREDIENTS OF THE GLASSES INCLUDE LITHIUM OXIDE AND ZINC OXIDE; THESE INGREDIENTS PROVIDE THE NECESSARY VISCOSITY REDUCTION SO THAT THE SAID FORMING PROCESSES CAN BE EMPLOYED. AFTER THE DESIRED GLASS ARTICLES ARE FORMED THEY CAN BE USED AS SUCH. HOWEVER, ANOTHER PRODUCT DISCLOSED IN THE APPLICATION IS THE PRODUCT OF HEAT TREATMENT OF THE GLASSES OF THE INVENTION. THE REMAINING TWO INGREDIENTS OF THE PRESENT COMPOSITIONS, ZIRCONIUM DIOXIDE AND TITANIUM DIOXIDE, CONTRIBUTE TO THE REDUCTION IN VISCOSITY OF THE GLASS MELTS. THEY ARE ALSO IMPORTANT IN AIDING IN FORMATION OF THE PRODUCTS OF HEAT TREATMENT OF THE PRESENT GLASSES, WHICH ARE LOW-EXPANSION CRYSTALLINE CERAMICS THAT CONTAIN A MULTIPLICITY OF VERY FINE CRYSTALS DISPERSED IN A GLASSY MATRIX. THE FOLLOWING SPECIFICATION DESCRIBES IN MORE DETAIL (1) HOW TO CARRY OUT THE HEAT TREATMENT, (2) THE PROPERTIES OF THE GLASSES AND (3) THE PROPERTIES OF THE CERAMICS WHICH ARE DERIVED FROM THE GLASSES.

Inventors

• 👤 Richard W Petticrew

Bibliographic Details