Low-temperature pressureless sintering of SiC ceramics with Al2O3-Y2O3-La2O3 addition

Silicon carbide (SiC) was pressurelessly sintered at lower temperature by using different oxides as sintering additives. The low sintering temperature was attributed to liquid-phase sintering of the eutectic liquid with or without the combination of Al2O3, Y2O3 and La2O3 formed at sintering temperature. The addition of La2O3 reduced the temperature of the liquid phase and stimulated the rearrangement of SiC powder and made it easy to separate out yttriferous and aluminiferous crystal. The improvement of chemical homogeneity in oxide additive by synthesized was favourable to the limit to volatilization of the oxide additive during sintering. The microstructure and mechanical property of the SiC based multiphase ceramics were sensitive to additive system, adding amount and sintering temperature.