Synthesis and Characterization of a Nearly Single Bulk TiAlN MAX Phase Obtained from Ti/AlN Powder Mixture through Spark Plasma Sintering.

MAX phases are an advanced class of ceramics based on ternary carbides or nitrides that combine some of the ceramic and metallic properties, which make them potential candidate materials for many engineering applications under severe conditions. The present work reports the successful synthesis of nearly single bulk TiAlN MAX phase (>98% purity) through solid-state reaction and from a Ti and AlN powder mixture in a molar ratio of 2:1 as starting materials. The mixture of Ti and AlN powders was subjected to reactive spark plasma sintering (SPS) under 30 MPa at 1200 °C and 1300 °C for 10 min in a vacuum atmosphere. It was found that the massive formation of AlO particles at the grain boundaries during sintering inhibits the development of the TiAlN MAX phase in the outer zone of the samples. The effect of sintering temperature on the microstructure and mechanical properties of the TiAlN MAX phase was investigated and discussed.