Abstract
The corrosion behavior and mechanism of PH13-8Mo stainless steel with and without nitric acid passivated film were studied through 5 years of outdoor exposure tests in industry-marine atmospheric environments in Qingdao, by means of morphological observation, weight-loss measurement, X-ray photoelectron spectroscopy (XPS) and Scanning Kelvin Probe (SKP). The results showed that the pre-passivation certainly inhibits the corrosion, but exhibits an obvious limitation of protection period for PH13-8Mo stainless steel in industrial-marine atmosphere. Compared with bare PH13-8Mo steel, the number and depth of pitting of pre-passivated steel were reduced, and the average corrosion rate decreased by 14.7%. The reasons of improved corrosion resistance included the higher ratio of Cr/Fe and oxide/hydroxide, and the more positive and homogeneous Kelvin voltage potential for the surface of outdoor exposed pre-passivated steel. Meanwhile, the pre-passivation film on the Cr-depleted regions caused by the Cr-rich precipitated phase was preferentially destructed in the atmosphere with Cl-, which decreased the protection period.
Highlights
PH13-8Mo is a martensitic age-strengthened stainless steel with a special grade of steel, which has ultra-high strength and toughness while maintaining good plasticity
Literatures revealed that the difference in the composition of the passivation film had a significant effect on the corrosion resistance of stainless steel in the marine atmosphere
It is well-known that passivation films on stainless steel are mainly composed of Cr and Fe oxides (Goutier et al, 2011; Escrivà-Cerdán et al, 2013) which play an important role in corrosion resistance
Summary
PH13-8Mo is a martensitic age-strengthened stainless steel with a special grade of steel, which has ultra-high strength and toughness while maintaining good plasticity. The influence of surface treatment of 304L stainless steel on atmospheric corrosion resistance was studied by Wallinder et al (2003). Literatures revealed that the difference in the composition of the passivation film had a significant effect on the corrosion resistance of stainless steel in the marine atmosphere. PH13-8Mo stainless steel samples with and without inorganic pre-passivated surface were exposed in Tuandao Cape for 5 years, and the corrosion behaviors of the steel were investigated. Where μ is the expected value, i.e., the focus position of the potential distribution; σ is the standard deviation of the distribution of the Gaussian analysis (i.e., the representative dispersion of the potential distribution; the larger the value, the larger the dispersion potential distribution) (Wang et al, 2019)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
