Microstructure, mechanical and tribological properties of NiAl matrix composites with addition of BaO/TiO2 binary oxides

Abstract BaO and TiO2 reacted and produced BaTiO3 in the process of sintering. As a result, the diffraction peaks of BaTiO3 became stronger with the increasing BaO/TiO2 contents. The diffraction peaks of NiAl shifted smaller angle to left with the addition of BaO/TiO2. Meanwhile, the lattice distortion obviously occurred in the composite structure. The composites with the addition of BaO/TiO2 presented high microhardness and yield strength as well. The composite with 20% BaO/TiO2 had the highest microhardness value and yield strength of 474.5 HV and 2786 MPa, respectively. The friction coefficient and wear rate of the composites decreased with the addition of BaO/TiO2 and the NiAl-30% BaO/TiO2 composite had the lowest friction coefficient at 800 °C test temperature. The BaTiO3 was decomposed to BaO and TiO2 during high temperature sliding.