Microstructural characteristics of the oxides formed on zinc contaminating stainless steel in high temperature water

The microstructure and phase composition were investigated for 304 stainless steel (SS) with Zn contaminant in 300 degrees C high temperature water. The synchrotron radiation-grazing incidence X-ray diffraction (SR-GIXRD) was employed to investigate the thin oxide structure. It is revealed that zinc contacted with 304 stainless steel by formation columnar zeta -FeZn13 particles and compact delta-FeZn10 grains. After 24 h high temperature water corrosion, 304 SS surface was primarily covered by ZnO, while the thin Fe2O3 oxides were detected by the analysis of the SR-GIXRD. The iron oxides were dominant for 240 h high temperature corrosion. The ZnO products were dissolved in the water environment causing the substrate evident degradation.