Corrosion resistance evaluation of highly dispersed MgO-MgAl₂O₄-ZrO₂ composite and analysis of its corrosion mechanism: A chromium-free refractory for RH refining kilns

The corrosion resistance behavior of a highly dispersed MgO-MgAl₂O₄-ZrO₂ composite refractory material is examined by testing with high-basicity and low-basicity RH (Ruhrstahl-Hereaeus) slags. The composite material exhibits greater resistance to the RH slags than the traditional MgO-Cr₂O₃ composite, MgO-ZrO₂ composite, and MgO-MgAl₂O₄-ZrO₂ composite. On the basis of the microstructural analysis and mechanisms calculations, the corrosion resistance behavior of the MgO-MgAl₂O₄-ZrO₂ composite is attributable to its highly dispersed structure, which helps protect the high activity of ZrO₂. When in contact with the slag, ZrO₂ reacts with CaO to form the stable phase CaZrO₃, which protects MgAl₂O₄ against corrosion, thereby enhancing the corrosion resistance of the composite.