Effect of stainless steel fibers on properties of MgO–C refractories

MgO–C refractories with stainless steel fibers were prepared to investigate the effects of stainless steel fibers addition on the thermal shock resistance, oxidation resistance, and microstructure of MgO–C refractories, and the optimum amount of stainless steel fibers was determined. The results showed that adding stainless steel fiber in MgO–C refractories can increase flexural strength and thermal shock resistance, with an optimal addition of 2 wt.%, owing to the bridging effect and crack deflection toughening of stainless steel fibers inside the material. The formation of MgAl1.9Fe0.1O4 composite spinel, which was responsible for higher oxidation resistance, produced volume expansion and prevented the diffusion of oxygen. The strengthening mechanism is physical embedding at room temperature, while it is reaction bonding at high temperature.