Mechanical, tribological and thermal properties of hot pressed ZrB2–SiC composite with SiC of different morphology

Abstract

ZrB2–SiC composites were prepared by hot pressing with different sources of SiC to study the effect of SiC with different morphology on densification, microstructure, phase composition and mechanical properties like hardness, fracture toughness and tribological properties (namely, scratch resistance, wear parameters) and thermal behaviour of the composites. Three different ZrB2–SiC composites, i.e. ZrB2–SiCP (polycarbosilane derived SiC), ZrB2–SiCC (SiC from CUMI, India) and ZrB2–SiCH (SiC from H. C. Starck, Germany), were studied. It is found that ZrB2–SiCC composite shows highest hardness (19·13 GPa) and fracture toughness (5·30 MPa m1/2 at 1 kgf load) in comparison with other composites. Interconnected network, better contiguity between grains of ZrB2–SiC composites and impurity content in starting powders can play significant roles for achieving high mechanical, tribological and thermal properties of the composites. Coefficient of friction and wear parameters of all ZrB2–SiC composites are very low, and thermal conductivity of ZrB2–SiC composites varied from 52·71 to 65·53 W (m K)−1 (ZrB2–SiCP), 54·30 to 71·55 W (m K)−1 (ZrB2–SiCC) and 64·25 to 88·02 W (m K)−1 (ZrB2–SiCH), respectively and also calculate the interfacial resistance of all the composites.