Microstructure and properties of SiC ceramic brazed with Zr–Cu composite filler metal

Abstract

The microstructure and properties of SiC ceramic brazed with Zr–Cu composite filler metal were investigated. Combined with the brazing experiment, the microstructure of the interface reaction layer and the brazed SiC ceramic joint was analyzed, and the shear strength was used to evaluate the mechanical properties of the joint. The results show that both Zr–Cu + SiC_p and Zr–Cu + Mo composite filler metals can braze SiC ceramic, and the products of the interface reaction layer are mainly ZrC and Zr₂Si. The addition of SiC_p and Mo to Zr–Cu-based composite filler metal improves the nuclear properties of the composite filler metal and its joint, reduces the coefficient of thermal expansion of the composite filler metal and SiC ceramic joint, and improves the mechanical properties of the joint. The shear properties of the joint increase with the increase of the content of SiCp and Mo in the Zr–Cu composite filler metals. The shear strength of the joint reaches the maximum (82 MPa) when the content of SiC particles is 10 vol% of the Zr–Cu + SiCp composite filler metal, and the average value of the shear strength reaches the maximum of 74 MPa when the content of Mo is 6 vol% of the Zr–Cu + Mo composite filler metal.