초록 ▼

Process for the moderately refractory assembly of at least two articles made of silicon carbide-based materials by non-reactive brazing in an oxidizing atmosphere, in which the articles are placed in contact with a non-reactive brazing composition and the assembly formed by the articles and the braz

Process for the moderately refractory assembly of at least two articles made of silicon carbide-based materials by non-reactive brazing in an oxidizing atmosphere, in which the articles are placed in contact with a non-reactive brazing composition and the assembly formed by the articles and the brazing composition is heated in an oxidizing atmosphere at a brazing temperature sufficient to melt the brazing composition so as to form a moderately refractory joint, wherein the non-reactive brazing composition is a composition A composed of silica (SiO2), alumina (Al2O3) and calcium oxide (CaO), or alternatively a composition B composed of alumina (Al2O3), calcium oxide (Cao) and magnesium oxide (MgO). Brazing suspension, paste comprising a powder of said brazing composition and an organic binder. Refractory joint and assembly.

대표청구항 ▼

1. A process for moderately refractory assembly of at least two articles made of silicon carbide-based materials by non-reactive brazing in an oxidizing atmosphere, the process consisting of: placing the at least two articles in contact with a non-reactive brazing composition to form an assembly; an

1. A process for moderately refractory assembly of at least two articles made of silicon carbide-based materials by non-reactive brazing in an oxidizing atmosphere, the process consisting of: placing the at least two articles in contact with a non-reactive brazing composition to form an assembly; andheating the assembly formed by the at least two articles and the non-reactive brazing composition under an oxidizing atmosphere to a brazing temperature that is sufficient to melt the non-reactive brazing composition in order to form a moderately refractory joint,wherein said oxidizing atmosphere remains present during said melting of the non-reactive brazing composition, andwherein, the non-reactive brazing composition is a composition A consisting of silica (SiO2), alumina (Al2O3) and calcium oxide (CaO) and optionally an addition of titanium oxide or an addition of boron oxide or both, or alternatively a composition B consisting of alumina (Al2O3), calcium oxide (CaO) and magnesium oxide (MgO) and optionally an addition of titanium oxide or an addition of boron oxide or both. 2. The process according to claim 1, wherein the oxidizing atmosphere is an atmosphere containing oxygen comprising an atmosphere of air, of oxygenated argon or of oxygenated helium. 3. The process according to claim 1, in which composition A is composed, as mass percentages, of 75% to 7% SiO2, 60% to 6% Al2O3 and 60% to 10% CaO. 4. The process according to claim 3, in which composition A is composed, as mass percentages, of 70% to 55% SiO2, 22% to 8% Al2O3 and 35% to 15% CaO. 5. The process according to claim 4, in which composition A is composed, as mass percentages, of 62% SiO2, 15% Al2O3 and 23% CaO. 6. The process according to claim 3, in which composition A is composed, as mass percentages, of 55% to 38% SiO2, 25% to 12% Al2O3 and 45% to 30% CaO. 7. The process according to claim 6, in which composition A is composed, as mass percentages, of 42% SiO2, 20% Al2O3 and 38% CaO. 8. The process according to claim 3, in which composition A is composed, as mass percentages, of 38% to 8% SiO2, 55% to 8% Al2O3 and 55% to 28% CaO. 9. The process according to claim 8, in which composition A is composed, as mass percentages, of 22% SiO2, 37% Al2O3 and 41% CaO. 10. The process according to claim 1, in which composition B is composed, as mass percentages, of 70% to 35% Al2O3, 65% to 25% CaO and 20% to 1% MgO. 11. The process according to claim 10, in which composition B is composed, as mass percentages, of 50.5% Al2O3, 44.0% CaO and 5.5% MgO. 12. The process according to claim 1, in which the brazing temperature is 1100° C. to 1650° C., andthe heating is performed at the brazing temperature for a time of 1 to 240 minutes. 13. The process according to claim 12, in which the brazing temperature is 1350° C. to 1650° C., andthe heating is performed at the brazing temperature for a time of 1 to 240 minutes. 14. The process according to claim 12, in which the heating is performed for a time of 2 to 30 minutes. 15. The process according to claim 1, in which the heating of the assembly formed by the at least two articles and the non-reactive brazing composition under the oxidizing atmosphere to the brazing temperature is achieved by introducing the assembly directly into a device already brought to the brazing temperature. 16. The process according to claim 15, in which the device is an oven. 17. The process according to claim 1, in which the heating of the assembly formed by the at least two articles and the non-reactive brazing composition under the oxidizing atmosphere to the brazing temperature is achieved by applying a temperature rise from room temperature. 18. The process according to claim 1, in which the silicon carbide-based materials are selected from among the group consisting of pure silicon carbides and SiC-based composite materials. 19. The process of claim 18, wherein the pure silicon carbides are pure α silicon carbide (α-SiC) or pure β silicon carbide (β-SiC). 20. The process of claim 18, wherein the SiC-based composite materials are a composite material with at least one selected from silicon carbide fibers and a silicon carbide matrix. 21. The process according to claim 1, in which the silicon carbide-based materials are selected from among the group consisting of pressureless sintered silicon carbide (PLS—SiC); Si-infiltrated silicon carbide (SiSiC or RBSC); porous recrystallized silicon carbide (RSiC); silicon graphite (C—SiC) composed of graphite and covered with a layer of SiC; SiC/SiC composites; C/SiC composites; SiC monocrystals; and SiC composites with another ceramic. 22. The process of claim 21, wherein the SiC/SiC composites contain fibers or “whiskers”. 23. The process of claim 21, wherein the C/SiC composites contain carbon fibers or “whiskers” and an SiC matrix. 24. The process of claim 21, wherein the SiC composites with another ceramic are SiC/Si3N4 or SiC/TiN. 25. The process according to claim 1, in which said silicon carbide-based materials have a silicon carbide content at least equal to 50% by mass. 26. The process according to claim 25, in which said silicon carbide-based materials have a silicon carbide content at least equal to 80% by mass. 27. The process according to claim 26, in which said silicon carbide-based materials have a silicon carbide content equal to 100% by mass. 28. The process of claim 1, wherein the at least two articles are shaped articles.