Effect of processing on toughness of Ca α-sialon ceramics.

The influence of processing on microstructural development of Ca α-sialon composition (Ca _xSi_{12−3 x}Al_{3 x}O _xN_{16− x}) with x = 1.8 was studied by dwelling at different intermediate temperatures before reaching the final sintering temperature. The microstructural observation results have showed the different aspect ratios of elongated grains obtained by the various processing conditions, reflecting the effect of the number of nuclei of α-sialon on morphology of grains during sintering. Improved toughness was achieved by applying low temperature dwelling for Ca α-sialon compositions with low x values. The toughness showed an increase of 33% and 16% for x = 0.6 and 1.0 compositions respectively with middle dwelling processing at 1350°C for 3 h before reaching 1750°C for 1 h by hot-pressing. [ABSTRACT FROM AUTHOR]