Improved corrosion performance of selective laser melted stainless steel 316L in the deep-sea environment
Yang Zhao, Hang Xiong, Xuanpeng Li, Wenlong Qi, Jidong Wang, Yong Hua, Tao Zhang, Fuhui Wang
Abstract
Through electrochemical and surface analysis, the composition, semi-conductive property and electrochemical performance of the passive film formed on selective laser melting stainless steel 316L (SLM SS316L) and wrought SS316L in the deep sea environment were analyzed, respectively. Results indicated that the corrosion resistance of SS316L can be enhanced by the SLM process, which is attributed to the greatly smaller grain size and higher density of grain boundaries. Grain boundary, i.e. metallurgical defects, enhances the dissolution of SS316L and releases a large quantity of Cr3+ ions at the interface. Then Cr(OH)3 precipitated and dehydrated to produce much more stable oxides Cr2O3. As a result, a thin and compact passive film formed on the SLM SS316L, which then suppressed localized corrosion and resulted in high corrosion resistance.