Impact of in-situ SiC whisker growth on MgO–Al2O3–C unfired refractories

To meet the refractory requirement for steel making process, an in-situ growth SiC whiskers enhanced MgO–Al2O3–C (MAC) refractories was developed. With adding catalyst, the SiC whiskers grew control at the working temperature (1400 °C) to improve the performance of MAC refractories. The effects of catalyst amounts and catalyst type on the SiC whiskers growth behavior and refractory performance was studied. As a results, with 0.8 wt% Ni(NO3)2 catalyst adding, the MAC refractory exhibited the highest, the CCS and CMOR values reached 56.50 MPa and 10.52 MPa, respectively. The thermal shock and oxidation resistance of MAC refractory was also enhanced through deflecting cracks and bridging mechanisms caused by SiC whiskers. Besides, according to experiment results and thermal dynamic calculation results, the SiC whisker grows follows a gas-liquid-solid (V-L-S) mechanism. This research work introduces a new method to boost the performance of refractories.