Effects of phenolic resin contents on microstructures and properties of c/sic-diamond composites

In this paper, C/SiC-diamond composites were obtained by chemical vapor infiltration (CVI) and reactive melt infiltration (RMI), and the effects of phenolic resin contents on the microstructures and properties of as-obtained C/SiC-diamond composites were studied. The results suggested a significant influence of phenolic resin contents on the pore structure of the composites before reactive melt infiltration (RMI), as well as phase composition and density of the matrix after RMI. The mechanical properties of composites were shown to correlate with the threshold effect of phenolic resin. Sample R5 prepared with high phenolic resin contents displayed significantly declined mechanical properties. On the other hand, adjustment of the phenolic resin content yielded samples with maximum room temperature thermal conductivity reaching 14.75 W/(m·K). The theoretical thermal conductivity of the composites calculated by the Hasselman-Johnson (H-J) theoretical model was estimated to 24.52 W/(m·K). Overall, the increase in phenolic resin content led to unreacted diamond-C regions and the formation of substantial porosity. These features reduced the thermal conductivity of the resulting C/SiC-diamond composites.