Pressureless sintering of La-Y-Sialon ceramics and
grain growth in later period of sintering
grain growth in later period of sintering
(State Key Laboratory for Powder Metallurgy,
Central South University,Changsha 410083, P.R.China)
Central South University,Changsha 410083, P.R.China)
Abstract: The pressureless sintering process of Sialon ceramics added (1.5% La2O3+4.5%Y2O3) as sintering aids was studied. It is found that a β′-Sialon with relative density over 99%is obtained by sintering at 1750℃ for 1h. Crystal grain growth was observed at room temperature by SEM for the samples sintered at 1800℃ 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 different activation energy. On the present conditions, logarithm of grain aspect ratio L￣/W￣ of average grain length L￣ to average width W￣ is in proportion to sintering time because of proportion of lgL￣to sintering time and proportion of W￣ to sintering time.
Key words: Sialon; grain growth; pressureless sintering