title: Copper corrosion by-product release in long-term stagnation experiments.
abstract: The effect of long-term stagnation on copper corrosion by-product release and corrosion rates was studied in pipe-rigs according to the German standard DIN 50931, Part 1. The analysis of the water phase was supplemented by surface analysis of corrosion scales. Copper concentration during stagnation did not follow a solubility process. The characteristic curves obtained can be explained by subsequent copper release and copper refixation processes. Oxygen consumption can be described by the first-order kinetic rate law. The corrosion scales consisted of cuprite (Cu2O) and malachite (CuCO3 x Cu(OH)2). Malachite grew in well-defined crystals during stagnation, served as sink for dissolved copper and did not protect the pipe against corrosion attack. Copper concentrations measured after long-term stagnation (up to 122 h) correspond to the solubility of malachite in the testwater.
authors: Heinrich-Sontheimer-Laboratory, DVGW-Water Technology Center Karlsruhe, Germany. merkel@tzw.de
authors: Till H
authors: TH
authors: Merkel
authors: Hans-Jürgen
authors: HJ
authors: Gross
authors: Wolfgang
authors: W
authors: Werner
authors: Thomas
authors: T
authors: Dahlke
authors: Susanne
authors: S
authors: Reicherter
authors: Günter
authors: G
authors: Beuchle
authors: Siegfried H
authors: SH
authors: Eberle
mesh_terms: D003300:Copper / Q000032:analysis* / Q000737:chemistry*; D003343:Corrosion; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008854:Microscopy, Electron; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D014877:Water Pollution, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis
chemical_list: D003300:Copper; D010100:Oxygen