Study on High Performance Fe3Si-Si3N4-SiC Composite Preparation and its Application in Blast Furnace

Excellent Fe3Si-Si3N4-SiC composites were successfully prepared with FeSi75 and SiC as main starting materials by nitridation reaction(at 1300°C for 8Hrs). The effect of ferrosilicon alloy addition amount on material properties was studied; the ferrosilicon nitridation mechanism was analyzed through chemical thermodynamics; phase composition, microstructure, alkali resistance of products were also investigated. The results show that when ferrosilicon addition amount is 12wt%, the comprehensive property of Fe3Si-Si3N4-SiC is the best. The nitridation products are fiber-like α-Si3N4 and rod-like β-Si3N4, which makes better mechanical behavior due to fiber reinforcement; a great deal of Fe3Si intermetallic compounds uniformly distribute in matrix, which is one of the products of Fe-Si nitridation and as a plastic phase forming in grain boundary optimizes the performance of products. Chemical thermodynamic analysis shows that the fiber-like α-Si3N4 is formed by SiO(g) and N2(g) reaction which also increases the rate of nitridation. Fe3Si-Si3N4-SiC material has good performance. Now it has been successfully applied to one 2000M3 domestic steel plant, the blast furnace operation goes well.