Corrosion of the WC-12Co and enamel coatings in liquid Zn-55Al alloy at 640 °C. (1st August 2021)

• Record Type: Journal Article
• Authors: Yu, Zhongdi; Chen, Minghui; Gao, Feng; Yu, Yueguang; Wang, Xin; Zhu, Shenglong; Wang, Fuhui
• Is Part Of: Corrosion science. Volume 188(2021)
• Publication Date: 2021-08-01
• Subjects: A. WC-12Co composite coating -- A. Enamel coating -- C. High temperature corrosion -- C. Liquid alloy; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2021.109559
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: Enamel coating provides higher corrosion resistance than WC-12Co coating. Co-Zn solid solution forms firstly at the corrosion front of the WC-12Co coating. Dissolution of Co-Al, Co-Zn phase and decarburization of WC degrade WC-12Co. γ-Al2 O3 grows on enamel coating can delay Ca dissolution and form CaAl4 O7 . CaAl4 O7 interlayer prevents Al permeation and provides high corrosion resistance. Abstract: Corrosion behavior of the WC-12Co and enamel coatings in liquid Zn-55Al alloy is investigated comparatively. Serious corrosion consumes over 40 μm of the WC-12Co coating after 100 h immersion. Co dissolution occurs firstly by forming Zn-Co solid solution and then intermetallic compounds. WC is decarburized and reacts with Al to form WAl5 at high temperature. The enamel coating suffers quite slight corrosion. Porous γ-Al2 O3 layer develops at surface, which then reacts with the enamel to form a continuous CaAl4 O7 interlayer that prevents the further invasion of Al and provides the high corrosion resistance.