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-MgAl 2 O 4 -ZrO 2 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-Cr 2 O 3 composite, MgO-ZrO 2 composite, and MgO-MgAl 2 O 4 -ZrO 2 composite. On the basis of the microstructural analysis and mechanisms calculations, the corrosion resistance behavior of the MgO-MgAl 2 O 4 -ZrO 2 composite is attributable to its highly dispersed structure, which helps protect the high activity of ZrO 2 . When in contact with the slag, ZrO 2 reacts with CaO to form the stable phase CaZrO 3 , which protects MgAl 2 O 4 against corrosion, thereby enhancing the corrosion resistance of the composite.