The effect of heat-treatment on the performance of sub-micron SiCp-reinforced alpha-beta sialon composites .2. Heat-treatment studies
Özet
The effects of heat-treatment on alpha --> beta sialon transformation in dense, agglomerate-free Ln-sialon/SiCp(Ln=Nd,Yb) composites are reported. The stability of the alpha-sialon phase is not only dependent on the temperature and time of heat-treatment, but also on the kind of additive and the amount of SiC particles. In Nd-densified Samples, the alpha-sialon phase is very unstable at 1450 degrees C and transforms, almost totally to the beta phase with the Nd-M (melilite) phase and NdAlO3 as grain-boundary crystalline phases. In contrast, Yb3+-densified samples show good stability for the alpha-sialon phase at 1450 degrees C, with only a small amount of beta-sialon produced. The crystalline grain-boundary phases produced in this case are Yb-garnet, and Yb-J-phase
