Bonding frits for ceramic composites

Claim 1

A method for sealing a fiber-reinforced alkaline earth aluminosilicate glass-ceramic matrix composite component into a refractory bonded assembly of two or more components which comprises the steps of: providing a thermally crystallizable alkaline earth aluminosilicate glass sealing frit between a first mating surface provided on said composite component and a second mating surface on at least one other component of the refractory bonded assembly; and while maintaining the first and second mating surfaces in contact with the glass sealing frit, heating at least the first and second mating surfaces and glass sealing frit to a temperature sufficient to melt and thermally crystallize the sealing frit; wherein the glass sealing frit has a composition selected from: I. glasses consisting essentially, in weight percent, of about 36-43% SiO2, 15-25% Al2O3, 20-25% BaO, 5-10% K2O, 0-1% As2O3, 0-5% ZrO2, and 0.5-6% B2O3, the glasses being thermally crystallizable to yield celsian as the principal crystal phase and potash feldspar as a minor phase; II. glasses consisting essentially, in weight percent, of about 43-53% SiO2, 24-36% Al2O3, 12-16% CaO, 2-7% K2O, 0-1% As2O3, 0-5% ZrO2, and 0-6% B2O3, the glasses being thermally crystallizable to yield anorthite as the principal crystal phase and potash feldspar as a minor phase; III. glasses consisting essentially, in weight percent, of about 35-55% SiO2, 25-37% Al2O3, 0.5-7% MgO, 1-8% K2O, 0-20% CaO, 0-1% As2O3, 0-6% ZrO2, and 0-6% B2O3, the glasses being thermally crystallizable to yield anorthite and/or cordierite as the principal crystal phases and potash feldspar as a minor phase; and IV. glasses consisting essentially, in weight percent, of about 35-42% SiO2, 34-46% Al2O3, 16-20% CaO, 0-1% As2O3, 0-5% ZrO2, and 0.5-5% B2O3, the glasses being thermally crystallizable to yield anorthite as the principal crystal phase and optionally comprising 0-15% by weight of a particulate ZrO2 additive intermixed therewith; said glass sealing frit exhibiting a thermal curing range of at least 150° C. between the flow temperature and the crystallization temperature of the frit, and being curable to a crystalline seal at a temperature not exceeding about 1150° C.

Claim 2

A method for sealing a fiber-reinforced alkaline earth aluminosilicate glass-ceramic matrix composite component into a refractory bonded assembly of two or more components which comprises the steps of: providing a thermally crystallizable alkaline earth aluminosilicate glass sealing frit between a first mating surface provided on said composite component and a second mating surface on at least one other component of the refractory bonded assembly; and while maintaining the first and second mating surfaces in contact with the glass sealing frit, heating at least the first and second mating surfaces and glass sealing frit to a temperature sufficient to melt and thermally crystallize the sealing frit; wherein the glass sealing frit has a composition selected from: I. glasses consisting essentially, in weight percent, of about 36-43% SiO2, 15-25% Al2O3, 20-25% BaO, 5-10% K2O, 0-1% As2O3, 0-5% ZrO2, and 0.5-6% B2O3, the glasses being thermally crystallizable to yield celsian as the principal crystal phase and potash feldspar as a minor phase; II. glasses consisting essentially, in weight percent, of about 43-53% SiO2, 24-36% Al2O3, 12-16% CaO, 2-7% K2O, 0-1% As2O3, 0-5% ZrO2, and 0-6% B2O3, the glasses being thermally crystallizable to yield anorthite as the principal crystal phase and potash feldspar as a minor phase; III. glasses consisting essentially, in weight percent, of about 35-55% SiO2, 25-37% Al2O3, 0.5-7% MgO, 1-8% K2O, 0-20% CaO, 0-1% As2O3, 0-6% ZrO2, and 0-6% B2O3, the glasses being thermally crystallizable to yield anorthite and/or cordierite as the principal crystal phases and potash feldspar as a minor phase; and IV. glasses consisting essentially, in weight percent, of about 35-42% SiO2, 34-46% Al2O3, 16-20% CaO, 0-1% As2O3, 0-5% ZrO2, and 0.5-5% B2O3, the glasses being thermally crystallizable to yield anorthite as the principal crystal phase and optionally comprising 0-15% by weight of a particulate ZrO2 additive intermixed therewith; said glass sealing frit exhibiting a thermal curing range of at least 150° C. between the flow temperature and the crystallization temperature of the frit, and being curable to a crystalline seal at a temperature not exceeding about 1150° C.