Crystallographic anisotropy of corrosion rate and surface faceting of polycrystalline 90Cu-10Ni in acidic NaCl solution

• Published in: Materials & design 2022-03, Vol.215, p.110429, Article 110429
• Main Authors: Yi, Xuening, Ma, Aili, Zhang, Lianmin, Zheng, Yugui
• Format: Article
• Language: English
• Subjects: 90Cu-10Ni alloy; AFM; Corrosion rate; Crystallographic anisotropy; Grain orientation; Surface faceting
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2022.110429

[Display omitted] •Statistics of 91 grains reveal the orientation-dependent corrosion rate following the order of (001) < (101) < (111).•A negative linear correlation is found between corrosion rate and θ(111) of grains.•Grains near (001), (111), (101), (112) show four different types of submicron-scale post-corrosion morphologies, respectively.•Each type of the faceted morphology is bounded by {001} planes which have the lowest corrosion rate.•Crystallographic models are established to explain the orientation-dependent surface faceting of grains. The orientation-dependent corrosion rate and surface faceting of polycrystalline 90Cu-10Ni in acidic NaCl solution was investigated statistically. A good linear relationship was found between corrosion rate and the deviation angle from the 〈111〉 direction of the grain. For the three principle low-index planes, the corrosion rates followed the sequence of (001) < (101) < (111). More interestingly, there is a clear correlation between crystallographic orientation and surface faceting of grains in 90Cu-10Ni. Grains orientated near the three principle low-index planes and the (112) plane exhibit four different types of submicron-scale post-corrosion morphologies, respectively. However, each type of the faceted structure is bounded by {001} planes which have the lowest corrosion rate, independent of the substrate grain orientation. This is supported by the crystallographic models and AFM topographic measurements. Current study provides a simple way to identify grain orientation by etching, and also promising solutions to optimize corrosion properties through tailoring surface texture and design micro- or nano-scale surface structure by controlled etching.