Interfacial reaction evolution of the ZrC ceramic joint diffusion bonded with Ni interlayer

ZrC ceramic was diffusion bonded with pure Ni as the interlayer to investigate its interaction mechanism. Results show that the Ni-ZrC interfacial reaction includes two characteristic stages: the solid phase diffusion and Ni-ZrC eutectic reaction. An atomic interdiffusion was observed during the solid phase diffusion stage and corresponding product was proven to be Ni-based solid solution, which transformed into Ni-Zr-C ternary eutectic around 1200 °C. Hereafter, the interfacial reaction transformed into a liquid phase reaction, which was in fact a dissolution process of ZrC into the liquid. The formed Ni-Zr-C ternary eutectic liquid permeated into the porous ZrC ceramic, leading to the formation of a thick transition layer. During the cooling period, graphite crystallized first from the liquid due to the dissolution change of C element. Decreasing in temperature, ZrC particles recrystallized from the liquid and the residual liquid solidified into Ni-based solid solution.