Effect of SiC Addition on Microstructure and Properties of Sintered SiC/Zr Composites in Vacuum

SiC/Zr composites of different composition were prepared by vacuum sintering, using SiC powder and ZrH₂ powder as the raw material. The effect of SiC addition on the microstructure and properties of SiC/Zr composite was studied. The results show that the compact and single Zr metal can be obtained without adding SiC, but the hardness and corrosion resistance are poor. After adding SiC, SiC reacts with Zr, and ZrC and Zr₂Si are produced. SiC particles are bounded well to Zr matrix by interfacial reaction layer, which lead to the higher hardness and corrosion resistance. With the rising of SiC addition, the relative density of the compact and sinter both decrease, while the second phase in the structure increases. The corrosion resistance of SiC/Zr composite is improved and the hardness increases initially and decreases afterwards. When the addition of SiC is 15%, the hardness reaches the maximum value. (authors)