Significant improvement of slag corrosion resistance and thermal shock resistance of corundum-based dry vibratable refractory by addition of Fe-Si3N4

Fe-Si3N4 was introduced to improve the service performance of corundum-based dry vibratable refractories in the casting industry, specifically enhancing their thermal shock resistance and resistance to slag corrosion. The study analyzed the effects of Fe-Si3N4 powder content on the refractories' mechanical properties, phase compositions, slag corrosion resistance, and microstructures. The addition of Fe-Si3N4 facilitated the production of magnesium aluminate spinel in the refractory matrix, while also decreasing the wettability between the molten slag and refractory. Increasing the Fe-Si3N4 content resulted in accelerating the replacing Mg2+ (0.072 nm) with Al3+ (0.053 nm) in the spinel. Simultaneously, Fe3+ (0.055 nm) was effectively dissolved into the alumina crystals. The bulk density, compressive strength, and slag corrosion resistance of the refractories were improved. However, the thermal shock resistance initially increased but then decreased. In industrial tests, a corundum-based dry vibratable refractory with a 1 wt.% Fe-Si3N4 content effectively prolonged the lifespan of an induction melting furnace when used as a lining refractory. Importantly, the refractory did not spall or generate cracks in the matrix after induction melt furnace industrial test.