Influence of Hot Pressing Temperature and SiC Content on the Microstructure and Mechanical Properties of ZrB2-SiC

The influence of hot pressing temperature and SIC content on the microstructure and mechanical properties of ZrB(2)-SiC ceramics was investigated. ZrB(2) containing 20 volume percent SiC were prepared by hot pressing at 1850, 1900 and 1950 degrees C for 60 min. Fully dense ceramic was obtained after hot pressing at temperature of 1950 degrees C. In addition, the materials with SiC content of 0, 10vol.%, 15 vol.%, 20 vol.% and 30 vol.% hot pressed at 1950 degrees C were also investigated. Results showed that the grain size of the ZrB(2) significantly reduced on adding 10vol.% SiC and then decreased slightly with further increasing SiC content, whereas the grain size of SiC exhibited a opposite trend. The flexural strength of ZrB(2)-SiC ceramics remarkedly increased on adding 10vol.% SiC due to the significant decrease of ZrB(2) particle size and then slightly increased with increasing SiC content up to 20vol.%. However, further increasing SiC content led to a reduction of the flexural strength.