The effect of surface treatment on the corrosion behavior of a pure Ta sheet in an equimolar NaCl–KCl melt at 850°C in air. Part 1: Laser surface melting. Issue 12 (13th September 2019)

• Record Type: Journal Article
• Authors: Hu, Ke; Hu, Shubing; Zeng, Siqi; Peng, Bo; Zhang, Yu; Xiao, Ming; Liu, Kaige; Wang, Xuerong; Liu, Wei; Wang, Kanghui; Yu, Wenkang; Lu, Xiaoxin; Yan, Wenjie
• Is Part Of: Materials and corrosion. Volume 70:Issue 12(2019)
• Page Start: 2205
• Page End: 2219
• Publication Date: 2019-09-13
• Subjects: chloride -- hot corrosion -- LSM -- oxidation -- Ta; Materials -- Periodicals; Metals -- Periodicals; Corrosion and anti-corrosives -- Periodicals; 620.1122305
• DOI: 10.1002/maco.201910974
• Languages: English
• ISSNs: 0947-5117

Abstract

Abstract: The corrosion behavior of pure Ta and laser surface melting–treated Ta sheets was investigated in an equimolar NaCl–KCl melt at 850°C in air. The results show that the predominant factors involved in the consumption of materials were reactions that form sodium‐containing oxides and Ta2 O5 . High corrosion stress led to slip of the untreated Ta surface grains, further resulting in preferential corrosion along slip bands. The slip of surface grains substantially deteriorated the bonding between the corrosion scale and matrix, thus leading to rapid degradation of the corrosion scale. The melt layer consisted of a thin Ta2 O5 film, and the inner dendrite layer demonstrated self‐healing characteristics during corrosion and presented a better hot corrosion resistance than the untreated Ta owing to the excellent bonding at the scale and melt layer interface. Abstract : The corrosion of Ta is promoted by basic/acid fluxing of Ta2 O5 at the Na–Ta–O/Ta–O interface and oxidation of Ta at the Ta–O/Ta interface. Preferential corrosion occurs along slip bands, thus forming tunnels that act as pathways to transport the corrosive media inward to cause corrosion. The preferential corrosion not only accelerates the consumption of metal but also substantially deteriorates the bonding of the corrosion scale with the Ta.