Method of forming a glass-ceramic to metal seals

Claim 1

A METHOD OF BONDING AN INSULATING MATERIAL TO A METAL MEMBER COMPRISING THE STEPS OF: A. APPLYING A COATING OF A BORON CONTAINING AQUEOUS SOLUTION HAVING A TEMPERATURE OF BETWEEN ABOUT 25*-100*C AND COMPRISING 0-10 WEIGHT PERCENT H3BO3 AND 10-30 WEIGHT PERCENT NA2B4O7, WHEREIN THE WEIGHT RATIO H3BO3 +NA2B4O7:H2O IS BETWEEN ABOUT 1:1.5 AND 1:9, TO A METAL MEMBER HAVING A COEFFICIENT OF THERMAL EXPANSION BETWEEN ABOUT 5 X 10**-6 IN/IN/*C TO 18 X 10**-6 IN/IN/*C; B. DRYING THE APPLIED SOLUTION TO FORM A BORON PRECIPITATE COATING HAVING A THICKNESS OF BETWEEN ABOUT 25-150 MICRONS; C. APPLYING A MOLTEN GLASS INSULATING MATERIAL, DIRECTLY TO THE COATED METAL MEMBER, AND HEATING THE INSULATING MATERIAL AND COATED METAL MEMBER UP TO A TEMPERATURE OF BETWEEN ABOUT 5000*-900*C, AT A TEMPERATURE RATE EFFECTIVE TO SIMULTANEOULSY FORM A SOLID INSULATING LAYER SELECTED FROM THE GROUP CONSISTING OF GLASS, AND GLASSCERAMIC HAVING A COEFFICIENT OF THERMAL EXPANSION BETWEEN ABOUT 0 TO 17 X 10**-6 IN/IN/*C, AND A BORON GLASS COATING ABOUT 25-150 MICRONS THICK CONSISTING ESSENTIALLY OF 30-50 WEIGHT PERCENT NA2O AND 50-70 WEIGHT PERCENT B2O3 HAVING A COEFFICIENT OF THERMAL EXPANSION BETWEEN ABOUT 8 X10**-6 IN/IN/*C TO 20 X 10**-6 IN/IN/*C, BETWEEN THE METAL MEMBER AND THE INSULATING LAYER; AND THEN D. COOLING THE INSULATED METAL MEMBER TO ROOM TEMPERATURE.

Claim 2

A METHOD OF BONDING AN INSULATING MATERIAL TO A METAL MEMBER COMPRISING THE STEPS OF: A. APPLYING A COATING OF A BORON CONTAINING AQUEOUS SOLUTION HAVING A TEMPERATURE OF BETWEEN ABOUT 25*-100*C AND COMPRISING 0-10 WEIGHT PERCENT H3BO3 AND 10-30 WEIGHT PERCENT NA2B4O7, WHEREIN THE WEIGHT RATIO H3BO3 +NA2B4O7:H2O IS BETWEEN ABOUT 1:1.5 AND 1:9, TO A METAL MEMBER HAVING A COEFFICIENT OF THERMAL EXPANSION BETWEEN ABOUT 5 X 10**-6 IN/IN/*C TO 18 X 10**-6 IN/IN/*C; B. DRYING THE APPLIED SOLUTION TO FORM A BORON PRECIPITATE COATING HAVING A THICKNESS OF BETWEEN ABOUT 25-150 MICRONS; C. APPLYING A MOLTEN GLASS INSULATING MATERIAL, DIRECTLY TO THE COATED METAL MEMBER, AND HEATING THE INSULATING MATERIAL AND COATED METAL MEMBER UP TO A TEMPERATURE OF BETWEEN ABOUT 5000*-900*C, AT A TEMPERATURE RATE EFFECTIVE TO SIMULTANEOULSY FORM A SOLID INSULATING LAYER SELECTED FROM THE GROUP CONSISTING OF GLASS, AND GLASSCERAMIC HAVING A COEFFICIENT OF THERMAL EXPANSION BETWEEN ABOUT 0 TO 17 X 10**-6 IN/IN/*C, AND A BORON GLASS COATING ABOUT 25-150 MICRONS THICK CONSISTING ESSENTIALLY OF 30-50 WEIGHT PERCENT NA2O AND 50-70 WEIGHT PERCENT B2O3 HAVING A COEFFICIENT OF THERMAL EXPANSION BETWEEN ABOUT 8 X10**-6 IN/IN/*C TO 20 X 10**-6 IN/IN/*C, BETWEEN THE METAL MEMBER AND THE INSULATING LAYER; AND THEN D. COOLING THE INSULATED METAL MEMBER TO ROOM TEMPERATURE.

Claim 9

A method of embedding a metal member in an electrically insulating glass-ceramic material comprising the steps of: A. applying a coating of an aqueous boron containing solution having a temperature of between about 25*-100*C and comprising 0-10 weight percent H3BO3 and 10-30 weight percent Na2B4O7, wherein the weight ratio H3BO3+Na2B4O7:H2O is between about 1: 1.5 and 1:9, to a metal member having a coefficient of thermal expansion between about 5 X 10 6 in/in/*C to 18 X 10 6 in/in/*C and an oxide coating having a thickness between about 0.8-10 microns; and then B. drying the applied solution at a temperature between about 50*-175*C to form a boron precipitate coating on the oxidized metal member having a thickness of between about 25-150 microns; and then C. placing the coated metal member in a mold; and then D. pouring a fluid glass composition Consisting essentially of about 60-80 weight percent SiO2, 12-20 weight percent Li2O, 1.0-6 weight percent P2O5, 0.5-7 weight percent of an alkali oxide selected from the group consisting of K2O and Na2O and their mixtures, 0-20 weight percent MgO, 0-10 weight percent Al2O3, 0-5 weight percent PbO, 0-2 weight percent of a transition metal oxide selected from the group consisting of Co3O4, MnO2, Fe2O3, V2O5 and WO3 and their mixtures and 0-1 weight percent As2O3 into the mold containing the coated metal member, to embed the metal member in the glass; and then E. cooling the glass to a temperature below about 600*C and then removing the mold; and then F. heating the glass and coated metal member up to a temperature of about 900*C at a rate of about 10*-80*C per hour, to form a glass-ceramic from the glass composition having a coefficient of thermal expansion between about 7 X 10 6 to 13 X 10 6 in/in/*C, said glass-ceramic being a substantially homogeneous micro-crystalline mass of ceramic in a glass matrix, and a boron glass coating between about 25-150 microns thick having a coefficient of thermal expansion between about 8 X 10 6 to 20 X 10 6 in/in/*C and consisting essentially of about 30-50 weight percent Na2O and about 50-70 weight percent B2O3, between the metal member and the glass-ceramic insulation; and finally G. cooling the glass-ceramic insulated metal member to room temperature to provide a hermetically sealed insulated article.

Claim 10

A method of embedding a metal member in an electrically insulating glass-ceramic material comprising the steps of: A. applying a coating of an aqueous boron containing solution having a temperature of between about 25*-100*C and comprising 0-10 weight percent H3BO3 and 10-30 weight percent Na2B4O7, wherein the weight ratio H3BO3+Na2B4O7:H2O is between about 1: 1.5 and 1:9, to a metal member having a coefficient of thermal expansion between about 5 X 10 6 in/in/*C to 18 X 10 6 in/in/*C and an oxide coating having a thickness between about 0.8-10 microns; and then B. drying the applied solution at a temperature between about 50*-175*C to form a boron precipitate coating on the oxidized metal member having a thickness of between about 25-150 microns; and then C. placing the coated metal member in a mold; and then D. pouring a fluid glass composition Consisting essentially of about 60-80 weight percent SiO2, 12-20 weight percent Li2O, 1.0-6 weight percent P2O5, 0.5-7 weight percent of an alkali oxide selected from the group consisting of K2O and Na2O and their mixtures, 0-20 weight percent MgO, 0-10 weight percent Al2O3, 0-5 weight percent PbO, 0-2 weight percent of a transition metal oxide selected from the group consisting of Co3O4, MnO2, Fe2O3, V2O5 and WO3 and their mixtures and 0-1 weight percent As2O3 into the mold containing the coated metal member, to embed the metal member in the glass; and then E. cooling the glass to a temperature below about 600*C and then removing the mold; and then F. heating the glass and coated metal member up to a temperature of about 900*C at a rate of about 10*-80*C per hour, to form a glass-ceramic from the glass composition having a coefficient of thermal expansion between about 7 X 10 6 to 13 X 10 6 in/in/*C, said glass-ceramic being a substantially homogeneous micro-crystalline mass of ceramic in a glass matrix, and a boron glass coating between about 25-150 microns thick having a coefficient of thermal expansion between about 8 X 10 6 to 20 X 10 6 in/in/*C and consisting essentially of about 30-50 weight percent Na2O and about 50-70 weight percent B2O3, between the metal member and the glass-ceramic insulation; and finally G. cooling the glass-ceramic insulated metal member to room temperature to provide a hermetically sealed insulated article.