Enhancing the thermal shock resistance of Al2O3-SiC-C castables via the generation of in-situ SiC whiskers

ABSTRACT The demand for Al2O3-SiC-C castables (ASCs) with excellent strength and thermal shock resistance has expanded considerably. Here, the effects of Fe-Si3N4 on the thermal shock resistance and physical properties of ASCs were studied. The addition of Fe-Si3N4 to ASCs lead to the formation of SiC whiskers, enhancing the cold modulus of rupture and the cold crushing strength of the castables. The formed SiC can fill the pores left by the oxidation of carbon after heating at 1450°C for 3 h, thereby improving the bulk density of the castables. Additionally, the residual strength ratio of the castables after three thermal shock cycles was improved and this was attributed to the generation of microcracks due to the release of N2 and the generation of the whiskers. The optimal Fe-Si3N4 content was 4 wt%. Therefore, the results of this study revealed that the thermal shock resistance and physical properties of ASCs were enhanced by the addition of Fe-Si3N4.