Effects of different catalysts on performance of self-bonded SiC refractories

Abstract The 3C–SiC whisker was catalytically synthesized with extended graphite and Si powder firing at 1573K using 1 wt% Fe, 3 wt% Co or 3 wt% Ni as catalysts, respectively. First-principles calculation results show the activities of the reactants of the synthesis of SiC could be increased via dwindling the bonding strength of C C, Si–O and C–O bonds. Furthermore, the performance of self-bonded SiC refractories prepared by the present catalytic method was enhanced including the mechanical properties (Fracture toughness of 1.35 MPa﹒m1/2 for the containing Fe catalysts samples, Fracture surface energy of 114 J﹒m−2 and MOR of 32.2 MPa (1473 K) for the sample with Ni catalysts), as well as the TSR (Residual MOR and Residual MOR percentage of 13.17 MPa and 62% at ΔT = 1075 K, respectively). The results indicate that the incorporation of catalysts decreased the reaction temperature by about 100 K as well as facilitated the in-situ formation of 3C–SiC whiskers, which interlinked and connected each other in the matrix of as-prepared self-bonded refractories and improved the high temperature properties. Among them, the Fe NPs presented the best catalytic activity.