A model for prolonged dezincification of α-brasses in 3% sodium chloride buffer solutions at different pH values

Corrosion-induced release of Cu and Zn into rainwater from brass, bronze and their pure metals. A 2-year field study

“…Brass can be selectively corroded through a dezincification process where zinc-rich surface regions are replaced with a porous layer of copper (Shreir et al 2000). Dezincification can be quantitatively expressed with a dezincification factor, defined as the quotient between the ratio of the zinc and copper content in solution and the corresponding ratio in the metal alloy (Rehan et al 2001). A factor exceeding 1 indicates that there is selective dissolution of zinc while a value of approximately 1 indicates uniform dissolution of the alloy.…”

“…This is in agreement with the dezincification mechanism previously described, i.e. the initial selective dissolution of zinc, followed by simultaneous dissolution of zinc and copper and subsequent re-deposition of copper (Dinnappa and Mayanna 1987;Marshakov 2002;Rehan et al 2001;Selvaraj et al 2003;Sundberg et al 2003). Annual release rates of copper and zinc from brass are significantly lower compared to the pure metals exposed to identical exposure conditions, Fig.…”

“…This can be quantified by calculating a factor of dezincification, Z f , (Rehan et al 2001), defined as the quotient between released zinc to copper in the runoff water compared to its nominal bulk alloy relation. This factor decreases from 13±5 for the first year of exposure, to 8±5 for the second year of exposure, showing the degree of dezincification to decrease with time (Fig.…”

“…According to recent experimental and theoretical findings, the first step of dezincification is the selective dissolution of zinc, forming structural defects such as mono-and di-vacancies in the surface layer which increases its free energy, and the subsequent propagation by simultaneous dissolution and re-deposition of copper (Dinnappa and Mayanna 1987;Marshakov 2002;Rehan et al 2001;Selvaraj et al 2003;Sundberg et al 2003).…”

“…(Dinnappa and Mayanna 1987;El-Sherif et al 2004;Mazza and Torchio 1983;Rehan et al 2001;Sastri 2005;Shreir et al 2000;Sundberg et al 2003). According to (Holm and Mattsson 1982), little or no dezincification is expected, neither for α-brasses with 15% zinc or less nor for arsenical α-brasses at atmosphere conditions.…”