Influence of Silicon Carbide Particle Size on the Microstructure and Mechanical Properties of Zirconium Diboride-silicon Carbide Ceramics

The influence of silicon carbide (SiC) particle size on the microstructure and mechanical properties of zirconium diboride-silicon carbide (ZrB2-SiC) ceramics was investigated. ZrB2-based ceramics containing 30vol.% SiC particles were prepared from four different α-SiC precursor powders with average particle sizes ranging from 0.45 to 10 μm. Examination of the dense ceramics showed that smaller starting SiC particle sizes led to improved densification, finer grain sizes, and higher strength. For example, ceramics prepared from SiC with the particle size of 10 μm had a strength of 389 MPa, but the strength increased to 909 MPa for ceramics prepared from SiC with a starting particle size of 0.45 μm. Analysis indicates that SiC particle size controls the strength of ZrB2-SiC.