No abstract

Powders of silicon nitride, aluminum nitride, and rare-earth oxides were weighed and mixed in an agate jar under absolute ethyl alcohol on a rotating mill for 2 h. Dried mixtures were hotmessed at 1700°C

R = La,Gd,Y) systems by XRD phase analyses of the solid-state reacted samples from powder mixtures of SiC, Si 3 N 4 , and R 2 O 3 . Subsolidus phase diagrams of these systems were presented and summarized. Within these systems in-situ SiO 2 impurity in the powder mixtures often cause the formation of some oxygen-richer rare-earth siliconoxynitrides, J-, K-, H-phases and extends the ternary systems SiC-Si 3 N 4 -R 2 O 3 into the quaternary systems SiC-Si 3 N 4 -SiO 2 -R 2 O 3 (Si-C-N-O-R). In these systems, the reaction of partial SiC participation and the formation mechanism of rare-earth siliconoxynitrides are discussed.