Solubilisation of nickel from powders at near-neutral pH and the role of oxide layers

• Published in: Corrosion science Vol. 51; no. 9; pp. 2043 - 2054
• Main Authors: Pulvirenti, April L., Bishop, Elizabeth J., Adel-Hadadi, Mohamad A., Barkatt, Aaron
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-09-2009; Elsevier
• Subjects: A. Nickel; Applied sciences; B. XRD; C. Atmospheric corrosion; C. Oxidation; C. Passive films; Corrosion; Corrosion environments; Exact sciences and technology; Metals. Metallurgy; A. Nickel; B. XRD; C. Oxidation; C. Passive films; C. Atmospheric corrosion; Oxide layer; Surface layer; pH; Oxidation; Passivity; Atmospheric corrosion; Passivation
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2009.05.029

Dissolution rates of nickel powder in pH 5 acetate buffers were observed to be an effective indicator of the thickness of the oxide layer on the surface of the nickel particle. Tests on powders pre-cleaned with acid or pre-oxidized in air demonstrated this dependence. The saturation level of nickel in the solution is not greatly affected by the initial state of the powder. Effects of additive solutes are most pronounced during short-term dissolution tests. Among such solutes, reduced sulphur and selenium species, phosphate, fluoride, oxalate, and permanganate cause the largest increases in dissolution rate, while hexacyanoferrate, arsenite, periodate, chromate, vanadate, molybdate, iodate, and tungstate suppress the dissolution.