Effects of Intermetallic NiAl Particle Content on Friction and Wear of Spark Plasma-Sintered Alumina Matrix Composites

The spark plasma sintering (SPS) technology was applied to develop alumina matrix composites (Al₂O₃MCs) with different nickel-aluminium (NiAl) particle contents of 5–20 wt.% to understand a correlation between their NiAl particle contents and their microstructures, fracture, hardness, friction, and wear. The incorporation of NiAl particles suppressed micrograins and micropores in the microstructures of the Al₂O₃MCs, which resulted in their improved fracture resistance. Increasing the NiAl particle content from 0 to 20 wt.% gave rise to a 23.9% decrease in the hardness of the Al₂O₃MCs. The Al₂O₃MCs had 18.2% and 13.3% decreases in their friction coefficients and 68.3% and 81.3% decreases in their specific wear rates under the normal loads of 2 and 6 N, respectively, with an increased NiAl particle content from 0 to 20 wt.% thanks to their decreased fatigue wear. The SPS Al₂O₃MCs with NiAl particles had promising tribological performance for rotating gas turbine components.