An Investigation on TiNi Intermetallic Produced by Electric Current Activated Sintering

In this study, TiNi intermetallic compounds were produced by electric current activated sintering in open air under an uniaxial pressure of 200 MPa at a maximum of 1200 A for 10 min using Ni powder (99.8% purity, 4-7 μm), Ti powder (99.5% purity, less than 44 μm). The elemental powders were mixed in the stoichiometric ratio corresponding to the TiNi intermetallic at molar proportion of 1:1. Scanning electron microscopy and X-ray diffraction analysis were used to characterize produced samples. X-ray diffraction studies revealed that the dominant phases are TiNi, $NiTi_2$, $Ni_3Ti$, TiO, and $Ni_2Ti_3$. Scanning electron microscopy examinations showed a dense microstructure with very low amount of porosity. The relative density of test materials measured according to Archimedes' principle was 96.8%, and the microhardness of materials was about 773.6 ± 123 $HV_{0.05}$.