Copper and Copper Alloys

Bi-modal trends in the long-term corrosion of copper and high copper alloys

“…marine organisms [8], and also under carbon or calcium carbonate deposits [41]. In addition, pitting for copper has been associated with de-aerated and low pH conditions inside pits or crevices [8].…”

“…Most investigations of the corrosion behaviour of copper and copper alloys have focused on short-term laboratory trials, electrochemical testing, examination of corrosion products, or relatively short field exposure programs [8,24], [25]. There are some exceptions, including the 20 year study of atmospheric corrosion for a range of almost pure coppers from various manufacturers exposed to 3 different atmospheric environments [26,27].…”

“…There has been more than a century of scientific study of the corrosion of copper, particularly in relation to its behaviour in seawater and in sulphur dioxide contaminated atmospheres [5,6,8]. In chlo-ride environments early investigations [9,10] identified the corro-sion products formed on copper to consist of mainly of cuprous oxide (Cu 2 O), cuprous chloride (CuCl) as well as other products including cupric hydroxide Cu(OH) 2 , cupric oxide CuO and to a les-ser extent, mainly in the outer layers of the corrosion product, the loosely adherent precipitation products atacamite (Cu 2 (OH) 3 Cl) and malachite (CuCO 3 ÁCu(OH) 2 ) [11].…”

An impedance study on admiralty brass dezincification originated by microbiologically influenced corrosion

“…A change in the Bode plots indicating increased corrosion activity is observed after 122 days, when the dezincification phenomenon, which hitherto appears in small areas starts to spread to large areas. It is suggested that the high zinc content in the alloy may contribute to the corrosion process, since dezincification is less expected when the zinc content is below 15% (Gilbert, 1994). The Bode plots exhibit a decrease in the impedance modulus and in the phase angle.…”

“…Dezincification is a known type of corrosion of copperzinc alloys which is due to de-alloying of the zinc metal. Two mechanisms have been proposed in the literature for the dezincification of brasses, involving on the one hand selective corrosion of the zinc in brass, leaving the copper in the matrix, and on the other hand complete dissolution of the brass followed by re-deposition of the copper (Gilbert, 1994).…”