Fabrication of a uniform chromate conversion coating on Zn alloy for improved corrosion resistance in humid environments.

Autor: Ha S; Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, Gyeongbuk, Republic of Korea., Eun J; Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, Gyeongbuk, Republic of Korea., Choi C; POSCO, 8 Pokposarang-Gil, Gwangyang-Si, Jeollanam-Do, Republic of Korea., Cho S; POSCO, 8 Pokposarang-Gil, Gwangyang-Si, Jeollanam-Do, Republic of Korea., Jeon S; Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, Gyeongbuk, Republic of Korea. jeons@postech.ac.kr.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2023 Aug 31; Vol. 13 (1), pp. 14311. Date of Electronic Publication: 2023 Aug 31.
DOI: 10.1038/s41598-023-41629-w
Abstrakt: We developed a facile method to produce a uniform chromate conversion (CC) coating on zinc alloy-plated steel substrates (ZS). When an acidic CC solution is applied to ZS (C-ZS), zinc is dissolved and chromium ions are reduced to form a chromate coating. In localized areas where zinc is excessively dissolved, zinc hydroxide particles are formed, which hinders the formation of a uniform chromate film, leaving the areas vulnerable to further corrosion (i.e., the formation of dark spots) when exposed to high humidity conditions. To suppress the excessive dissolution of zinc, the ZS surface was pretreated with thiolated polyethylene oxide to form a hydrophilic self-assembled monolayer. A more uniform protective CC coating was obtained on the pretreated ZS, resulting in superior corrosion resistance under high humidity conditions.
(© 2023. Springer Nature Limited.)
Databáze: MEDLINE
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