Study on AlON phase evolution and densification behavior as a function of particle size and doping amount

Abstract

Three groups of AlON powders with D50 = 0.5, 1.1 and 2.7 μm (referred as P0.5, P1.1 and P2.7) were prepared to study the pressureless sintering behavior of AlON. These powders were doped with 0−0.75 wt.% Y2O3 to investigate the combined effect of powder size and doping amount on the phase transformation, microstructure evolution and densification process during heating. The addition of high additive amount to P0.5 and P1.1 powders resulted in massive transformation into α-Al2O3 and AlN, which resulted in agglomeration of α-Al2O3 and isolation of AlN. Although low amount of additive to all three powders can effectively inhibit agglomeration of α-Al2O3 and homogenization of particle size before sintering, its sintering ability is insufficient. 0.05, 0.10 and 0.50 wt.% Y2O3 is the optimal addition to P0.5, P1.1 and P2.7 powders, respectively, to obtain high density, i.e. the larger of AlON powder size, the more Y2O3 is needed.