Optimizing the La₂O₃ concentration for enhanced thermal and wear resistance of Ti(C,N)-based cermets

Ti(C,N)-based cermets are important materials for cutting tools and wear-resistant applications because of their excellent hardness, and thermal stability. Nevertheless, enhancing their efficiency by improving the microstructure, mechanical properties, and wear resistance is still complicated. This work examined how La₂O₃ addition affects the microstructure, mechanical properties, thermal stability, and tribological performance of Ti(C,N)-based cermets. Ball milling and vacuum sintering were used to produce the samples containing various La₂O₃ contents. Ball-on-disk wear tests were used to examine the tribological properties of Ti(C,N)-based cermets. The incorporation of La₂O₃ improved the microstructure of samples by refining the grain size of hard phase. La₂O₃ enhanced the mechanical properties of Ti(C,N)-based cermets, achieving a maximum Vicker's hardness of 1640 Kg_f/mm² (L1 cermet with 0.5 wt% La₂O₃) and fracture toughness of 10.0 MPa.m1/2 (L3 cermet with 1.5 wt% La₂O₃). However, the incorporation of excessive La₂O₃ minimizes transverse rupture strength (TRS) from 1495 MPa (T sample) to 900 MPa (L3 cermet). Among these three La₂O₃ contents, Ti(C,N)-based cermet incorporated with 1.0 wt% La₂O₃ (L2 cermet) has the highest wear resistance, with a wear rate of 2.49 × 10−6 mm³/(Nm).