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 ZrB2-MoSi2-SiCw (ZMSw) composites. Four ZrB2-MoSi2 composites containing various amounts of SiCw (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 ZrB2-based ceramic-matrix composite with core-rim grain structure in the boride matrix, where ZrB2 core is surrounded by a solid solution of (Mo,W)Si2. Fragmentation, rearrangement, plastic deformation, and grain boundary diffusion mechanisms are responsible for densification of composites sintered by multistage SPS conditions at 1700 degrees C. Addition of SiCw significantly improves the density and mechanical properties of ZrB2-MoSi2-SiCw composites due to the formation of a corerim structure.