Kinetic Study of Vacuum Titanizing on Porous Iron by Ti and TiH2

Iron foam was successfully coated with titanium by a titanizing process. For titanizing, source sponge titanium must have high purity and a large surface area to evaporate effectively in a vacuum at high temperature. The titanizing process consisted of (1) the evaporation of high purity sponge titanium, producing titanium hydride at 1073-1123 K and 10(-5) torr for 10 hours, (2) the reaction between titanium gases and the surface of porous iron, and (3) the formation of Fe-Ti alloy by thermal diffusion. The kinetics of titanizing on the surface of ferrous iron applied to source materials such as sponge Ti and TiH2 were systematically investigated in this study. The characterizations of microstructure by SEM and analysis of chemical composition and EDS were also performed to understand the kinetics of titanizing.