The formation mechanism and effect of amorphous SiO2 on the corrosion behaviour of Fe-Cr-Si ODS alloy in LBE at 550 °C

• The corrosion behaviour of the developed Fe-Cr-Si ODS in LBE at 550 °C was studied. • The oxide scale/matrix interface features were investigated using the FIB and TEM. • Amorphous SiO 2 particles formed preferentially at the inner oxide layer, and delayed the growth of the outer magnetite layer. • SiO 2 promoted the formation of Cr-rich oxides and reduced the interface defects. The corrosion behaviour of the newly developed Fe-Cr-Si oxide-dispersion-strengthened alloys in liquid lead–bismuth eutectic at 550 °C was microstructurally studied. The corrosion resistance was enhanced with increasing Si content, attributing to the preferred formation of amorphous SiO 2 during the inward diffusion of oxygen. SiO 2 promoted the formation of Cr-rich oxides that were uniformly distributed in the inner-oxide layer and matrix, thereby reducing the Fe and O diffusion coefficients and ultimately delaying the formation of the outer magnetite layer and the growth of the inner Cr-rich oxide layer while reducing interfacial defects.