Premium
Effect of Chloride Ion Concentration on the Galvanic Corrosion of α Phase Brass by Eccrine Sweat
Author(s) -
Meekins Andrew,
Bond John W.,
Chaloner Penelope
Publication year - 2012
Publication title -
journal of forensic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.715
H-Index - 96
eISSN - 1556-4029
pISSN - 0022-1198
DOI - 10.1111/j.1556-4029.2012.02063.x
Subject(s) - chloride , brass , sodium , chemistry , copper , corrosion , zinc , calcium , inductively coupled plasma , inorganic chemistry , ion , metal , potassium , plasma , physics , organic chemistry , quantum mechanics
Inductively coupled plasma mass spectrometry measurement of the relative concentration of sodium, chloride, calcium, and potassium ions in eccrine sweat deposits from 40 donors revealed positive correlations between chloride and sodium ( ρ = 0.684, p < 0.01) and chloride and calcium ions ( ρ = 0.91, p < 0.01). Correlations between ion concentration and the corrosion of α phase brass by the donated sweat were investigated by visual grading of the degree of corrosion, by measuring the copper/zinc ratio using energy‐dispersive X‐ray spectroscopy, and from a measurement of the potential difference between corroded and uncorroded brass when a large potential was applied to the uncorroded brass. An increasing copper/zinc ratio (indicative of dezincification) was found to correlate positively to both chloride ion concentration and visual grading of corrosion, while visual grading gave correlations with potential difference measurements that were indicative of the preferential surface oxidation of zinc rather than copper.