Pressureless sintering of La-Y-Sialon ceramics and grain growth in later period of sintering

摘要

The pressureless sintering process of Sialon ceramics added (1.5/100 La_2O_3+4.5/100 Y_2O_3) as sintering aids was studied. It is found that a β'-Sialon with relative density over 99/100 is obtained by sintering at 1750 deg. C for 1 h. Crys- tal grain growth was observed at room temperature by SEM for the samples sintered at 1 800 deg. C holding for different time. It is proved that grain-growth along c-axis of β'-phase is a first priority, since (210) and (001) lattice plans have differ- Ent activation energy. On the present conditions, logarithm of grain aspect ratio L/W of average grain length L to aver- Age width W is in proportion to sintering time because of proportion of lgL to sintering time and proportion of W to sin- Tering time.