The wide used of the mullite ceramics can be explained by their distinctive high-temperature properties such as high thermal and pressure stability in harsh oxidising enviroments favourable thermal shock, as well as high chemical resistance both to alkali and acid media. These properties can be achieved largely by complete densification in the process of sintering by using advance sintering techniques such as spark plasma sintering, hot pressing inter alia. One of the possible ways could be the modification of the primary composition of mullite-ZrO2 ceramics by Si3N4 taking into account the fact that such an additive could promote the densification of the ceramic. This phenomenon is based on the fact during sintering the reaction with oxides occuring on the surface of Si3O4 particles create a liquid phase, thus promoting the diffusion processes and finally leading to densification of the product.
In the present work, a comparative study has be done to explore a Si3N4 additive effect on mullite-ZrO2/Y2O3 ceramics structure, phase composition, and certain other properties of ceramics sintered by SPS and compared to traditionally sintered ones.