The passivity of selective laser melted 316L stainless steel

• Published in: Applied surface science Vol. 504; p. 144495
• Main Authors: Kong, Decheng, Dong, Chaofang, Ni, Xiaoqing, Zhang, Liang, Luo, Hong, Li, Ruixue, Wang, Li, Man, Cheng, Li, Xiaogang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 28.02.2020
• Subjects: AFM; Cellular structure; Passive film; Selective laser melting; Stainless steel; AFM; Passive film; Selective laser melting; Stainless steel; Cellular structure
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.144495

[Display omitted] •High sub-grain boundary density increased the nucleation of passive film.•Micro-galvanic effect accelerated the rapid formation of passive film.•Re-passive ability of the SLMed 316L without pore was equal to the wrought.•Widely precipitated oxide and sulphide particles led to poor corrosion resistance for SA SLMed 316L. The passive film properties of as-received selective laser-melted 316L stainless steel (SLMed 316L SS) without obvious pores were studied and compared with those of wrought and solution-annealed (SA) SLMed 316L SSs. Among the samples, the as-received SLMed 316L SS had the lowest passive current density, which was attributed to two factors: the super high sub-grain boundary density increased the number of nucleation sites for passive film formation, and the micro-galvanic effect between the sub-grain boundary and the inner sub-grains also accelerated the rapid formation of a thick protective layer. The poor passivation and re-passivation abilities of the SA SLMed 316L SS were ascribed to the extensively precipitated nanosized oxide and sulfide particles, especially those at the grain boundary.