Effects of Aluminum, Silicon And Ferro Silicon Anti Oxidants in MgO C Refractories

  Three different materials (aluminum, ferro -silicon and silicon) were used as antioxidants in order to prevent the decarburization process and to keep and/or increase the final properties in MgO-C refractories. Their effects were compared by measuring the physical and mechanical properties as well as oxidation and the resultant phases and microstructures, in the temperature range of ۲۰۰-۱۶۰۰ °C. High temperature oxidation was measured up to ۱۰۰۰ °C. The impurities of the aluminum and silicon powders were less than ۱%. The ferro-silicon contains ۲-۵% Al, and ۱۰-۲۰% Fe. Results indicate that the oxidation of the samples were much better in the ferrosilicon than aluminum and silicon cases. The CCS measurements indicate more improvements due to the effects of ferro-silicon than silicon case. Results indicate that aluminum is more effective at low temperature. However, at higher temperatures, the other two anti-oxidants are more effective. The phase analysis indicates that the reaction of M۲S phase with other phases might cause some reduction of high temperature behaviors. Also, Phase analysis indicates the formation of MgO-FeO/Fe۲O۳ phase, aluminum and silicon carbides as well as Spinel phase in the samples.