Atomic layer deposition of Al2O3 thin films for corrosion protections of additive manufactured and wrought stainless steels 316L

• Published in: Materials letters Vol. 331; p. 133434
• Main Authors: Gong, Na, Seet, Hangli, Cao, Jing, Luai Meng, Tzee, Wang, Yong, Tan, Dennis C.C., Kiang Ivan Tan, Chee, Suwardi, Ady, Zhu, Qiang, Blackwood, Daniel J., Ling Sharon Nai, Mui, Liu, Hongfei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.01.2023
• Subjects: Additive manufacturing; Atomic layer deposition; Electrochemical corrosion; Protective coating; Stainless steel; Protective coating; Additive manufacturing; Atomic layer deposition; Electrochemical corrosion; Stainless steel
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2022.133434

[Display omitted] •Electrochemical corrosions have been compared for AM- and wrought-SS316L.•AM-SS316L has a better corrosion resistance than that of wrough-SS316L.•Corrosion of AM-SS316L is dominated by defect-assisted cracking.•Corrosion of wrought-SS316L is dominated by pitting without cracking.•ALD coating of Al2O3 significantly enhanced the corrosion resistance. We report atomic layer deposition (ALD) of Al2O3 films and their effect on corrosion resistance of additively manufactured (AM) and wrought stainless steel (SS) 316L. Electrochemical polarization and impedance spectroscopy provide evidence that the Al2O3 coatings increased the corrosion resistance of the AM- and wrought-SS316L by lowering the corrosion current and enhancing the active passivation. The corrosion resistant enhancement on AM-SS316L (by ∼ 53.8%) is much more significant than that on wrought-SS316L (by ∼ 2.6%). The difference has been discussed and associated with the corrosion-induced morphological changes, i.e., corrosion pits are much less on AM-SS316L than on wrough-SS316L and, instead, microcracks emerged on AM-SS316L rather than on wrought-SS316L. The corrosion-induced microcracks in the vicinal regions of structural defects on AM-SS316L are consistent with its residual localized strains.