Open AccessInvestigation of slurry erosion-corrosion behavior of Ta(Si1−xAlx)2 nanocrystalline coatings
Author(s) -
Jiang Xu,
Qingwen Xie,
Shuang Peng,
Zhengyang Li,
Shuyun Jiang
Publication year - 2020
Publication title -
materials research express
Language(s) - English
Resource type - Journals
ISSN - 2053-1591
DOI - 10.1088/2053-1591/ab6f39
Subject(s) - materials science , slurry , nanocrystalline material , corrosion , coating , equiaxed crystals , metallurgy , erosion corrosion , alloy , electrochemistry , cathode , composite material , nanotechnology , chemistry , electrode
To enhance the erosion-corrosion resistance of titanium alloys, two Ta(Si 1−x Al x ) 2 coatings with different Al content were deposited on Ti−6Al−4V alloy by double cathode glow discharge method. The coatings consist of single hexagonal C40 structured TaSi 2 phase, which forms an equiaxed grain structure with an average diameter of ∼5 nm. Al addition was found to enhance the values of H/E and adhesive strength between the substrate and coating. The erosion–corrosion behavior of the coatings was studied in a liquid–solid acid slurry flow (specifically a medium of 5 wt% HCl solution that contained a 10 wt% concentration of silica-based sand) using electrochemical measurements, weight loss tests and SEM observation. The results indicated that the ternary Ta(Si 0.875 Al 0.125 ) 2 coating provided better protection, compared to the binary TaSi 2 coating, against the combined attack of mechanical erosion and electrochemical corrosion in a liquid–solid acid slurry flow. This is attributable to high self-healing ability of the surface passive film and a higher H/E ratio.