Phase and microstructural evolution of low carbon MgO-C refractories with addition of Fe-catalyzed phenolic resin

Abstract In the present paper, phase and microstructural characterization of low carbon MgO-C refractories with addition of Fe-catalyzed phenolic resins as binder were investigated. Initially, phenolic resin was modified using various amounts of Fe particles as catalyst originated from iron nitrate ([Fe(NO3)3·9H2O]). The MgO-C matrix compositions were prepared by using 7% of modified phenolic resin, shaped and cured at 200 °C for 24 h. The cured samples were coked in the temperature range from 800 to 1400 °C and then characterized by XRD and FE-SEM techniques. Based on attained results, in-situ graphitic carbons, particularly in carbon nanotubes (CNTs) network were gradually formed from Fe-catalyzed phenolic resin in the matrix of MgO-C refractory bodies. It was also clarified in comparison with sample containing as-received phenolic resin, more ceramic whiskers such as Al4C3, AlN, MgO and MgAl2O4 were formed in the matrix of MgO-C specimens with addition of Fe-catalyzed phenolic resin binder and significally increased with coking temperature. Microstructural observation showed the graphitic carbons like CNTs and ceramic whiskers mainly formed in the bonding phase between the aggregates, that certainly leads to enhancement of physical and mechanical properties of MgO-C refractories.