Research on High Performance Fe3Si-Si3N4-SiC Composite Used for Blast Furnace

Abstract

Excellent Fe 3 Si-Si 3 N 4 -SiC composites were successfully prepared with FeSi75 and SiC as main starting materials by nitridation reaction(at 1300°C for 8Hrs). The material properties were studied; the ferrosilicon nitridation mechanism was analyzed through chemical thermodynamics; phase composition, microstructure, corrosion resistance of products were also investigated. The results are shown that the comprehensive properties of Fe 3 Si-Si 3 N 4 -SiC are outstanding. The nitridation products are fiber-like -Si 3 N 4 and rod-like -Si 3 N 4 , which makes better mechanical behavior due to fiber reinforcement; a great deal of Fe 3 Si 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 is shown that the fiber-like -Si 3 N 4 is formed by SiO(g) and N 2 (g) reaction which also increases the rate of nitridation. Fe 3 Si-Si 3 N 4 -SiC material has high corrosion resistance. Now it has been successfully applied to one 2000M 3 domestic steel plant, the blast furnace operation goes well.

Silicon nitridation mechanism in reaction‐bonded Si3N4–SiC and Si3N4‐bonded ferrosilicon nitride

“…We suspect that the existence of gaseous SiO leads to the matter loss during silicon nitridation and causes the low nitridation rate of Si. We also notice that in the process of Si 3 N 4 ‐bonded ferrosilicon nitride production at the same condition as Si 3 N 4 –SiC, there is no fibrous α‐Si 3 N 4 generated which means hardly any gaseous SiO is generated during silicon nitridation. Therefore, the difference of nitridation mechanism of silicon in producing Si 3 N 4 ‐bonded ferrosilicon nitride and Si 3 N 4 –SiC is analyzed in order to explore a way to increase Si nitridation rate at low cost.…”