Interaction of liquid tin and zinc with AISI 304 stainless steel after passivation in air and nitric acid

The reaction of liquid Sn and Zn with passivated AISI 304 stainless steel has been investigated by analyzing the growth of interfacial intermetallic layers. Both Sn and Zn are prone to metallurgically react with ground stainless steel by the formation of interfacial (Fe, Cr)Sn2 and ζ-(Fe, Cr)Zn13, δ-(Fe, Cr)Zn10 intermetallics, respectively. The native oxide film grown in air has retarded the growth of (Fe, Cr)Sn2 layer. The chemical oxide film grown in nitric acid has prevented the formation of (Fe, Cr)Sn2 layer and changed the metallurgical combination to physical attachment. In the liquid Zn, both native and chemical oxide films become unstable and slightly decrease the growth of intermetallic layer. It is supposed that the composition and structure differences in those two oxide films and the fast diffusion of zinc at relatively high temperature are responsible for the instability of oxide film and the growth of the intermetallic Fe–Zn compound.