Interfacial microstructure and mechanical properties of SiC joints achieved by reactive air brazing using Ag-V2O5 filler

SiC ceramics are successfully brazed via reactive air brazing using Ag-V2O5 fillers. The wettability of SiC ceramics by Ag-V2O5 fillers is investigated. Interfacial microstructure of SiC joints is analyzed by scanning electron microscopy and transmission electron microscopy with energy dispersive spectroscopy. Effect of the brazing filler composition on the microstructure and mechanical properties of SiC joints is studied in detail. The V2O5 from the brazing fillers is found to react intensively with SiC, and the SiO2 reaction layer with the thickness of (similar to)7 mu m is formed on the SiC surface which ensures a good wetting of the brazing filler on SiC ceramics. The brazing seam is composed of Ag and VO2 with small amount of remaining V2O5. The maximum shear strength ((similar to)58 MPa) is achieved when using the optimized brazing process (Ag-8V(2)O(5), 1050 degrees C/30 min, the loading pressure is (similar to)20 kPa and the cooling rate is 2 degrees C/min).