Fabrication of TiN-Ni and TiN-Co Cermets by Mechanical Milling and Subsequent Pulsed Current Sintering and Their Fracture Strength

TiN-Ni and TiN-Co cermets were fabricated by mechanical milling of TiN and Ni or Co powders, followed by pulsed current sintering. The microstructure of the TiN-Ni and TiN-Co cermet samples prepared from the non-milled powder contained a large number of pores. However, these pores were eliminated from both the sintered samples through mechanical milling of the powders. Relative densities of over 98% were achieved. Mechanical milling also improved the three-point bending strength of the cermet samples. In this study, the samples sintered from the powders milled for 28.8 ks exhibited the maximum strength, i.e., the strength of TiN-Ni and TiN-Co ceremets was 1.4 and 1.2 GPa, respectively. The fracture surface of the sample sintered from the non-milled powders was intergranular whereas that of the sample sintered from the milled powder was both intergranular and transgranular in nature. [doi:10.2320/matertrans.MBW201109]