Effect of Zr addition on intergranular corrosion of low-chromium ferritic stainless steel

Addition of Zr to low-Cr ferritic stainless steel forms a mixture of ZrC and Fe23Zr6 precipitates that can prevent intergranular corrosion. Transmission electron microscopy and three-dimensional atom probe analysis suggest that the ZrC and Fe23Zr6 mixture prevents intergranular corrosion in two ways: by acting as a strong carbide former to suppress the formation of Cr-carbide and by acting as a barrier against the diffusion of the solute Cr towards the grain boundary.