Microstructural evolution and growth kinetics of interfacial reaction layers in SUS430/Ti3SiC2 diffusion bonded joints using a Ni interlayer

Ti₃SiC₂ ceramic and SUS430 stainless steel (SS) were successfully joined by a solid diffusion bonding technique using Ni interlayers. Diffusion bonding was performed in the temperature range of 850 °C–1100 °C under vacuum. The interfacial reaction phase, morphology evolution, growth kinetics and tensile strength were systematically investigated. In all cases, the inter-diffusion and reaction between Ti₃SiC₂ and SS can be effectively prevented by Ni foil, and the good transition in the joint benefit to the sound joining. The interface in the joints adjacent to SS matrix was composed of γ solid solution and a small amount of σ intermetallic compound. The compounds in the Ni/Ti₃SiC₂ interface was Ni/Ni(Si)/Ni₃₁Si₁₂ + Ni₁₆Ti₆Si₇ + Ti₃SiC₂ + TiC_x/Ti₂Ni + Ti₃SiC₂ + TiC_x/Ti₃SiC₂, which formed by the inter-diffusion and chemical reactions between Si and Ni atoms. The diffusion mechanism and reaction mechanism were interrelated, and decided the width of each reaction zones. Furthermore, the diffusion activation energy was 113 kJ/mol. The tensile strength increases with increasing the bonding temperature. The minimum and maximum strength of 32.3 MPa and 88.8 MPa were obtained from SUS430/Ni/Ti₃SiC₂ joints, which bonding experiments were carried out at 850 °C and 1100 °C, respectively.