Effect of microstructure and passive film on corrosion resistance of 2507 super duplex stainless steel prepared by different cooling methods in simulated marine environment
来源期刊：International Journal of Minerals Metallurgy and Materials2020年第8期
论文作者：Min Zhu Qiang Zhang Yong-feng Yuan Shao-yi Guo
文章页码：1100 - 1114
摘 要：The effect of microstructure and passive film on the corrosion resistance of 2507 super duplex stainless steel（SDSS） in simulated marine environment was investigated by electrochemical measurements, periodic wet–dry cyclic corrosion test, scanning Kelvin probe force microscopy, atomic force microscopy, and X-ray photoelectron spectrometry. The results show that the occupation ratio of γ phase increases with the decrease in cooling rate, whereas the content of α phase reduces gradually. In addition, the σ precipitated phase only emerges in the annealed steel. The pitting sensitivity and corrosion rate of 2507 SDSS reduce first and then increase as the cooling rate decreases. The σ precipitated phase drastically reduces the protective ability of the passive film and facilitates micro-galvanic corrosion of the annealed steel. For various microstructures, the pits are preferentially distributed within the σ and γ phases. The corrosion resistance of 2507 SDSS prepared by different cooling methods is closely related to the microstructure and structure（stability and homogeneity） of the passive film. Normalized steel shows an optimal corrosion resistance, followed by the quenched and annealed steels.
Min Zhu1,2，Qiang Zhang1，Yong-feng Yuan1，Shao-yi Guo1
1. School of Mechanical Engineering & Automation, Zhejiang Sci-Tech University2. National and Local Joint Engineering Research Center of Reliability Analysis and Testing for Mechanical and Electrical Products, Zhejiang Sci-Tech University
摘 要：The effect of microstructure and passive film on the corrosion resistance of 2507 super duplex stainless steel（SDSS） in simulated marine environment was investigated by electrochemical measurements, periodic wet–dry cyclic corrosion test, scanning Kelvin probe force microscopy, atomic force microscopy, and X-ray photoelectron spectrometry. The results show that the occupation ratio of γ phase increases with the decrease in cooling rate, whereas the content of α phase reduces gradually. In addition, the σ precipitated phase only emerges in the annealed steel. The pitting sensitivity and corrosion rate of 2507 SDSS reduce first and then increase as the cooling rate decreases. The σ precipitated phase drastically reduces the protective ability of the passive film and facilitates micro-galvanic corrosion of the annealed steel. For various microstructures, the pits are preferentially distributed within the σ and γ phases. The corrosion resistance of 2507 SDSS prepared by different cooling methods is closely related to the microstructure and structure（stability and homogeneity） of the passive film. Normalized steel shows an optimal corrosion resistance, followed by the quenched and annealed steels.
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