The effect of SiC-CVD coating on the flexural strength of metal boride particle dispersed SiC was investigated. Compressive residual stress was detected in the CVD-SiC coating on the TiB
2/SiC specimen. The compressive residual stress was thought to arise during the cooling process from the CVD processing temperature, i. e., from 1300°C to an ambient temperature because of the larger coefficient of thermal expansion of TiB
2/SiC as compared to CVD-SiC. The compressive residual stress increased with the volume fraction of TiB
2. The CVD coating layer fractured and separated from TiB
2/SiC at volume fractions of TiB
2≥35 vol%. The compressive residual stress stored in the SiC-CVD coating affected the flexural strength of CVD coated TiB
2/SiC. The flexural strength increased by the CVD coating from 583 to 767MPa at room temperature. The flexural strength was decreased by the SiC-CVD from 767 to 610MPa at 1450°C. The change of flexural strength of SiC-CVD coated TiB
2/SiC with temperature was thought to be related to the evolution of thermal residual stress. At lower temperature than the CVD processing temperature, the compressive residual stress induced on the surface of CVD coating enhanced the flexural strength of TiB
2/SiC. On the other hand, higher temperatures than the CVD processing temperature, tensile stress was induced on the surface CVD coating and the flexural strength of TiB
2/SiC decreased.
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