Abstract: The invention provides a process for the production of sialon ceramic (and a sialon ceramic produced by such a process) comprising or including the steps of: (I) preparing a sialon reactant mixture including or comprising: a) silicon metal; b) clay; and c) a secondary aluminium source; (II) heating the reactant mixture in an atmosphere containing nitrogen gas to a temperature sufficient to substantially react the silicon metal, the secondary aluminium source and the nitrogen with the clay to form or to contribute to the forming of the sialon product; wherein the clay participates in the reaction as a source of aluminium and silicon. Further, the invention provides a method for preparing a sialon ceramic in a predetermined shape.

Abstract: A process for the production of .alpha.' or .beta.'SiAlON from a starting mixture of silicon metal and clay, wherein the process includes heating the mixture in a flowing nitrogen, or nitrogen containing, atmosphere to a temperature sufficient to react the silicon and the nitrogen with the clay to form the .beta.' or .alpha.'SiAlON and wherein the clay participates in the reaction as a source of aluminium and silicon.