Densification behavior of ZrB2–MoSi2–SiCw composite processed by multi stage spark plasma sintering.

This study reports the densification behavior and novel design of core-rim microstructure for different ZrB 2 –MoSi 2 -SiC w (ZMS w) composites. Four ZrB 2 –MoSi 2 composites containing various amounts of SiC w (0, 5, 10, and 20 vol%) were densified by multistage spark plasma sintering. Optimal combinations of sintering schedule, temperature, and composition are recognized for producing dense ZrB 2 -based ceramic-matrix composite with core-rim grain structure in the boride matrix, where ZrB 2 core is surrounded by a solid solution of (Mo,W)Si 2. Fragmentation, rearrangement, plastic deformation, and grain boundary diffusion mechanisms are responsible for densification of composites sintered by multistage SPS conditions at 1700 °C. Addition of SiC w significantly improves the density and mechanical properties of ZrB 2 –MoSi 2 –SiC w composites due to the formation of a core-rim structure. [ABSTRACT FROM AUTHOR]