Interfacial reaction between solid Ni and liquid Al in tens of seconds: Dissolution kinetics of solid Ni and formation of intermetallic compounds

Abstract The interfacial reaction between solid Ni and liquid Al, such as dissolution behaviors of solid Ni and formation mechanisms of intermetallic compounds, are not thoroughly clarified yet, especially under the conditions of short holding time and high reaction temperature. In this study, a hot-dip method was designed to investigate the isothermal interfacial reaction mechanism of solid Ni and liquid Al at temperature of 700 °C, 800 °C and 900 °C for 0–40 s. The dissolution behavior of solid Ni in liquid Al was analyzed. The dissolution rate constant, KNi, and dissolution activation energy, Ea, were calculated. The microstructure analysis with scanning electron microscope (SEM) and transmission electron microscopy (TEM) revealed that the dissolved thickness of solid Ni in pure liquid Al has linear relationship with the reaction time. The microstructure of the reaction interface consisted of Ni, Ni based solid solution, Al3Ni2 layer, adhered Al3Ni layer, free Al3Ni, Al3Ni + Al eutectic structure and Al. Ni based solid solution structure firstly formed at the holding stage. Nano-scale Al3Ni2 and irregular adhered Al3Ni appeared at the interface during fast cooling stage.