Claims
- 1. A process of bonding a plurality of thermally stable, high strength, graphite fiber reinforced glass matrix composite materials together comprising applying to the surface of at least one of the composite materials to be bonded, a mixture of a low softening point glass and a high softening point-low coefficient of thermal expansion material in such proportions that at bonding temperatures the constituents in the mixture interdiffuse to form a bond material with a bond strength greater than 7.times.10.sup.3 psi (4.92.times.10.sup.6 kgs per square meter).
- 2. A process of bonding a plurality of thermally stable, high strength, graphite fiber reinforced glass matrix composite materials together comprising applying to the surface of at least one of the composite materials to be bonded, a mixture of low softening point, high lead oxide content glaze, low coefficient of thermal expansion beta-spodumene and colloidal silica, placing the two composite surfaces to be bonded together with the bonding material between them, and hot pressing the composite materials under inert atmosphere to form a high strength bonded composite material with bond strength greater than 7.times.10.sup.3 psi (4.92.times.10.sup.6 kgs per square meter).
- 3. The process of claim 1 wherein the bonding mixture is applied to both of the surfaces to be bonded.
- 4. The process of claim 2 wherein the high lead oxide content glaze has a thermal expansion coefficient of about 52.times.10.sup.-7 cm/cm.degree. C.
- 5. The process of claim 2 wherein the hot pressing takes place at pressures up to 300 pounds per square inch (2.069.times.10.sup.6 NT/M.sup.2) at temperatures up to 800.degree. C.
- 6. The process of claim 1 wherein the glass matrix comprises borosilicate.
- 7. The process of claim 1 wherein the graphite fibers have a modulus of elasticity of at least 531 GPa, a tensile strength of at least 1724 MPa and a density of about 1.96 gm/cm.sup.3.
- 8. The process of claim 1 wherein the composite contains 40% to 70% by volume graphite fibers having orientation in the composite of 0.degree. and 90.degree.; 0.degree., 45.degree. and 90.degree.; 0.degree. and 60.degree.; or are discontinuous.
- 9. The process of claim 2 wherein the bonding composition comprises, by weight, about 47% to 50% high lead oxide content glaze, about 46% to 49% beta-spodumene, and about 1% to 7% colloidal silica.
- 10. A bonded composite material comprising a plurality of individual thermally stable high strength graphite fiber reinforced glass matrix composite components bonded together with a bond material comprising a mixture of low coefficient of thermal expansion high lead oxide content glaze, low coefficient of thermal expansion beta-spodumene, and colloidal silica, the bonded composite having a bond strength greater than 7.times.10.sup.3 pounds per square inch (4.827.times.10.sup.7 NT/M.sup.2).
- 11. The article of claim 10 wherein the bond material has a thermal expansion coefficient up to 10% greater than that of the composite glass matrix.
- 12. The article of claim 10 wherein the bond material has a thermal expansion coefficient of approximately 25.times.10.sup.-7 cm/cm.degree. C.
- 13. The product of claim 10 wherein the glass matrix comprises borosilicate glass.
- 14. The product of claim 10 wherein the graphite fibers have a modulus of elasticity of at least 531 GPa, a tensile strength of at least 1724 MPa and a density of about 1.96 gm/cm.sup.3.
- 15. The product of claim 10 wherein the composite contains 40% to 70% by volume graphite fibers having orientation in the composite of 0.degree. and 90.degree.; 0.degree., 45.degree. and 90.degree.; 0.degree. and 60.degree.; or are discontinuous.
Government Interests
The Government has rights in this invention pursuant to Contract No. NAS1-14346 awarded by the National Aeronautics and Space Administration.
US Referenced Citations (12)