Synthesis and Sintering of MgAlON: Influence of Sintering Additives

MgAlON ceramics were prepared by combined use of self-propagating high-temperature synthesis of Al + Al₂O₃ + MgO + Mg(ClO₄)₂ mixtures doped with sintering agent LiF, CaCO₃ or La₂O₃ + Y₂O₃ + MgO and pressureless sintering. The effect of additives on the combustion process and phase formation of synthesized products, as well as their subsequent sintering was studied. Introduction of 10 wt % CaCO₃ was shown to lower the combustion temperature followed by stopping the combustion front. It was revealed that the density of sintered ceramic materials reaches 90% of the theoretical value. The sintered sample prepared by doping with 0.6 wt % CaCO₃ was found to possess the highest density (3.3 g/cm³) and light transmittance (16%).