Textured alpha-SiAION Ceramics Via Templated Grain Growth

In this study, textured a-SiAION ceramic was produced by templated grain growth process. In order to enhance the alignment of the seeds, gated tape casting arrangement was utilized. Y-Ce codoped seeds were synthesized to induce the preferred orientation. For the production of the seeds, Ce3 was used as a sintering additive due to its well-known effect on the formation of elongated alpha-SiAION grains. In addition, Y3+ was used to stabilize Ce3+ in a-SiAION structure. Gated tape casting arrangement was also used to enhance the alignment of the seeds in the green tape. After the lamination and sintering, preferentially aligned alpha-SiAION grains were observed by the microstructural investigation. In addition, XRD results obtained from the planes parallel and perpendicular to the casting direction indicated the alignment of grains in alpha-SiAlON ceramics. Hardness measurements also confirmed that the alignment of the grains results in 8% increase in hardness value of the plane perpendicular to the casting direction with respect to that of the parallel one.