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Nanoscale Investigation of the Impact of pH and Orthophosphate on the Corrosion of Copper Surfaces in Water
Citation:
Lewandowski, B. R., D. A. LYTLE, AND J. C. Garno. Nanoscale Investigation of the Impact of pH and Orthophosphate on the Corrosion of Copper Surfaces in Water . LANGMUIR. American Chemical Society, Washington, DC, 26(18):14671-14679, (2010).
Impact/Purpose:
To inform the public.
Description:
Advanced surface characterization techniques were used to systematically investigate the passivation of copper during corrosion in water as impacted by pH and orthophosphate. Atomic force microscopy, depth profiling with time-of-flight secondary ion mass spectrometry and X-ray diffraction were used to evaluate changes in the nanoscale morphology and surface chemistry of copper surfaces resulting from various chemical treatments. Nanoscale differences in surface morphology are clearly evident after 6 and 24 hours immersion in water samples. Orthophosphate and pH dramatically influence the evolution and progression of changes during surface corrosion. For example, the surface of copper exposed to water at pH 6.5 in the absence of orthophosphate produced relatively large cubic crystals up to 400 nm in height. In the presence of orthophosphate, the morphology and growth rate of corrosion by-products changed dramatically, and the formation of identifiable crystals diminished. These investigations provide insight on the mechanisms of surface passivation and the evolution of nanoscale mineral deposits on surfaces at early stages of the corrosion of copper in water.
