Investigation on Ni-Al Intermetallic Compounds Fabricated through Reactive Sintering Processes

The utilization of nickel aluminide compounds in high-temperature structural applications is advantageous due to their desirable properties. One efficient method for producing nickel aluminide samples with desirable chemical reactions using minimal energy is reactive sintering. In this study, Ni-Al (20 wt.%-80 wt.%) compounds were fabricated by initially cold pressing them, followed by reactive sintering. The reactive sintering process resulted in the formation of NiAl3 and Ni2Al3 phases within the Ni-Al compounds. The microstructure, porosity, and hardness of the samples were thoroughly examined and analyzed. Generally, the compounds produced through reactive sintering exhibited significant porosity attributed to shrinkage and the Kirkendall effect. Microstructural analysis confirmed the presence of porosity, NiAl3, and Ni2Al3 phases. The sintered sample processed at 400 °C demonstrated higher density and hardness. Additionally, the wear test indicated a low wear rate and friction coefficient for the sintered sample processed at 400 °C.