The Fate of Copper During Corrosion of Cu-5Zn-5Al-1Sn (89% Cu, 5% Zn, 5% Al, 1% Sn) Compared to Copper in Synthetic Perspiration Solution

Cu-5Zn-5Al-1Sn (89% Cu, 5% Zn, 5% Al, 1% Sn) and UNS C11000 copper (Cu) were compared with respect to corrosion rate, film formation, and Cu release in two surface conditions pertinent to the use of antimicrobial functional materials. Electrochemical, surface characterization, and solution analysis methods were utilized to track the fate of copper during corrosion in synthetic perspiration solution in a freshly ground condition and after 30-d lab air passivation. Corrosion behavior was a function of both alloy composition and surface condition with slightly lower corrosion rates on Cu-5Zn-5Al-1Sn compared to Cu. Throughout the corrosion process, the majority of Cu was observed to undergo dissolution into the synthetic perspiration solution as copper cations for both materials, at concentrations that would suggest favorable antimicrobial functionality for both Cu-5Zn-5Al-1Sn and Cu, regardless of surface condition. In contrast, oxide films were thinner on Cu-5Zn-5Al-1Sn under all conditions. Hence, the combination of a slightly lower corrosion rate and a thinner oxide resulted in a similar Cu release rate for the two materials in synthetic perspiration.