Interfacial reaction mechanism between multi-component oxides and solid alloys deoxidised by Mn and Si during heat treatment

To clarify the interfacial reaction mechanism between multi-component oxides and solid Mn- and Si-deoxidised alloys during heat treatment, five diffusion couples with different compositions of Fe–Mn–Si alloy and CaO–SiO2–Al2O3–MgO–MnO oxide were produced using a confocal scanning laser microscope. The changes in the chemical compositions of the oxide and alloy by heat treatment at 1273 and 1473 K were investigated. The mechanisms of the ‘solid–solid’ and ‘solid–liquid’ interfacial reactions and the diffusion of elements between the alloy and oxide were revealed thermodynamically and are discussed. The results show that counter-diffusion occurring between Mn and Si in the alloy and oxide was the main reaction in the diffusion couples. The MnO content of the oxide and the Si content of the alloy are the driving forces of the interfacial reactions.