Relationship between microstructure and abrasive wear resistance of Al 2O 3–FeAl 2O 4 nanocomposites produced via solid-state precipitation

Abstract

The work investigates the correlation between the microstructure and wear behaviour of novel Al 2O 3–FeAl 2O 4 nanocomposites, developed by precipitation of FeAl 2O 4 particles through reduction aging of Al 2O 3–10 wt.% Fe 2O 3 solid solutions in N 2/4%H 2. Reduction aging at 1450 °C for 10 and 20 h resulted in considerable improvements in abrasive wear resistance. The nanocomposites developed from solid solutions doped additionally with ∼250 ppm of Y 2O 3 contained finer intergranular second phase particles (by a factor of ∼2) and showed further improvements in the wear resistance. Doped nanocomposites reduction aged for 20 h at 1450 °C exhibited the minimum wear rate (reduced by a factor of ∼2.5 with respect to monolithic Al 2O 3). The suppression of fracture-induced surface pullout in the presence of intragranular nanosized second phase particles was the major factor responsible for the improved wear resistance of the nanocomposites with respect to monolithic alumina; microstructures without these intragranular nanoparticles showed no improvement. Higher aging temperature led to the presence of coarse (>2 μm) intergranular FeAl 2O 4 particles which had a detrimental effect on the wear resistance.