Corrosion resistance enhancement of WC cermet coating by carbides alloying. (February 2019)

• Record Type: Journal Article
• Authors: Wang, Haibin; Lu, Hao; Song, Xiaoyan; Yan, Xifeng; Liu, Xuemei; Nie, Zuoren
• Is Part Of: Corrosion science. Volume 147(2019)
• Page Start: 372
• Page End: 383
• Publication Date: 2019-02
• Subjects: Cermet coating -- Cr alloying -- Surface potential -- Corrosion resistance -- Micro-galvanic effect; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2018.11.028
• Languages: English
• ISSNs: 0010-938X

Abstract

Graphical abstract: The potential difference between the carbides and metallic binder was significantly decreased owing to Cr dissolution in carbides. Accordingly, the prepared WC-Co2 Cr3 coating obtained remarkably enhanced corrosion resistance (the corrosion current density was decreased by one order of magnitude from that of the conventional coating). A new mechanism of reducing surface potential by carbides alloying was proposed for high corrosion resistance of cermet coatings. Highlights: A unique WC-Co2 Cr3 powder was designed to prepare the WC cermet coating. New mechanism of reducing surface potential by carbides alloying was proposed. The electrochemical corrosion resistance of the coating was remarkably enhanced. Abstract: A new type of WC-based coating was prepared using a specially designed WC-Co2 Cr3 powder. The microstructure and corrosion resistance of the present coating were examined and compared with those of the conventional WC-10Co-4Cr coating. It was found that Cr dissolved homogeneously in Co, WC and W2 C phases in the WC-Co2 Cr3 coating. However, in the conventional coating Cr mainly exists in Co. The potential difference between the carbides and metallic binder was significantly decreased in the WC-Co2 Cr3 coating owing to Cr dissolution in carbides. The resistance against the micro-galvanic corrosion is then remarkably enhanced compared to the conventional WC-based coating.