Glasses and glass-ceramics and products made therefrom

Abstract

Abstract 1. IN A RECUPERATOR MATRIX COMPRISING AN ASSEMBLY OF INTEGRALLY FUSED TUBES ARRANGED IN A PLURALITY OF LAYERS OF TUBES SUPERIMPOSED ONE ABOVE THE OTHER IN SUCCESSIVE PARALLEL PLANES, THE TUBES WITHIN EACH PLANE BEING ESSENTIALLY PARALLEL TO EACH OTHER AND TRANSVERSE TO THE TUBES IN ADJACENT LAYERS, THE TUBES IN EACH LAYER FORMING A SERIES OF LONGITUDINAL PARALLEL PASSAGEWAYS THROUGH THE MATRIX, WHEREIN THE WALLS OF SAID PASSAGEWAYS (1) HAVE ESSENTIALLY ZERO POROSITY, AND (2) CONSIST ESSENTIALLY OF AN INORGANIC CRYSTALLINE OXIDE CERAMIC MATERIAL, AND WHEREIN THE INNER DIAMETER OF SAID PASSAGEWAYS IS AT LEAST 3 TIMES THE WALL THICKNESS THROUGH PORTIONS OF SAID WALLS COMMON TO ADJACENT FUSED TUBES, WHEREIN THE OPEN FRONTAL OR CROSS-SECTIONAL AREA OF EACH FACE OF THE MATRIX CONTAINING PASSAGEWAYS IS AT LEAST 32 PERCENT OF THE CROSSSECTIONAL AREA ACROSS SUCH FACE, THE IMPROVEMENT WHEREBY SUCH RECUPERATOR MATRIX CAN WITHSTAND TEMPERATURES OF 1500*F. FOR AT LEAST 1000 HOURS AND SAID MATRIX WILL HAVE A DIMENSIONAL STABILITY OF LESS THAN 250 P.P.M. AND WILL RETAIN ITS STRENGTH, COMPRISING HAVING SAID INORGANIC CRYSTALLINE OXIDE CERAMIC MATERIAL OF SAID MATRIX CONSIST ESSENTIALLY OF THE GLASS-CERAMIC FORMED BY THERMALLY IN SITU CRYSTALLIZING A GLASS CONSISTING ESSENTIALLY OF THE FOLLOWING INGREDIENTS: INGREDIENTS: WEIGHT PERCENT SIO2 52-78.4 AL2O3 12.8-27.5 LI2O 2.4-7 ZNO 0.25-6.7 NUCLEATING AGENT 3-9 WHEREIN SAID NUCLEATING AGENT IS SELECTED FROM THE GROUP CONSISTING OF TIO2, ZRO2 AND A MIXTURE OF TIO2 AND ZRO2 AND WHEN SAID NUCLEATING AGENT IS TIO2, IT IS PRESENT IN AN AMOUNT OF AT LEAST 3.2 PERCENT AND WHEN SAID NUCLEATING AGENT IS ZRO2 OR THE MIXTURE, THE ZRO2 IS PRESENT IN AN AMOUNT NOT IN EXCESS OF 3% BY WEIGHT, WHEREIN THE ZNO+LI2O/AL2O3 MOLAR RATIO IS $1, AND WHEREIN THE SIO2/AL2O3 MOLAR RATIO IS FROM 4 TO 9 AND (A) WHEN THE SIO2/AL2O3 MOLAR RATIO IS FROM 4 TO LESS THAN 5, THE LI2O/AL2O3 MOLAR RATIO IS FROM 0.55 TO 0.91, AND THE ZNO/LI2O MOLAR RATIO IS FROM 0.06 TO 0.5; (B) WHEN THE SIO2/AL2O3 MOLAR RATIO IS FROM 5 TO 8, THE LI2O/AL2O3 MOLAR RATIO IS FROM 0.55 TO 0.93, AND THE ZNO/LI2O MOLAR RATIO IS FROM 0.04 TO 0.5; (C) WHEN THE SIO2/AL2O3 MOLAR RATIO IS FROM MORE THAN 8 UP TO 9, THE LI2O/AL2O3 MOLAR RATIO IS FROM 0.8 TO 0.93, AND THE ZNO/LI2O MOLAR RATIO IS FROM 0.04 TO 0.5; AND (D) THE GLASS AND RESULTING GLASS-CERAMIC CONTAINS IN WEIGHT PERCENT NO MORE THAN 0.2 K2O, OR 0.2 NA2O, OR 0.2 (NA2O+K2O), SAID GLASS-CERAMIC HAVING A COEFFICIENT OF LINEAR THERMAL EXPANSION OF -12 TO +12X10**-7 (0700*C.).

Inventors

• 👤 J Planchock
• 👤 D Stewart
• 👤 T Brock

Bibliographic Details