Microstructure evolution in HIPed AlON and its effect on optical property

Transparent aluminium oxynitride (AlON) ceramics were prepared by hot isostatic pressing (HIP) with 0.08 similar to 0.14 wt% Y2O3 or 0.01 similar to 0.04 wt% La2O3 as sintering additives. Both Y2O3 and La2O3 additives prompted sintering process and accelerated grain growth. When higher amount of Y2O3 (0.12 wt%) or La2O3 (0.03 wt%) additives were doped, extensive twins occurred accompanied with the coarsing of grain size (similar to 100 mu m). Electron backscatter diffraction (EBSD) analysis showed that twin boundaries increased with the increasing of Y2O3/La2O3 concentrations. By co-doping of Y2O3-La2O3 additives with reduced doping level, the formation of twins was successfully suppressed, which was necessary to limit the additional light scattering of twin boundaries. (C) 2015 Optical Society of America