Autoria: MITRE, C. I. N.; PARIS, E. C.; LOBO, C. M. S.; ROTH, C.; COLNAGO, L. A.

Resumo: The corrosion of metals is a major problem of modern societies, demanding new technologies and studies to understand and minimize it. Here we evaluated the effect of a magnetic field (B) on the corrosion of copper in aqueous HCl solution under open circuit potential. The corrosion product, Cu2+, is a paramagnetic ion and its concentration in the solution was determined in real time in the corrosion cell by time-domain NMR relaxometry. The results show that the magnetic field (B = 0.23 T) of the time-domain NMR instrument reduces the corrosion rate by almost 50%, in comparison to when the corrosion reaction is performed in the absence of B. Atomic force microscopy and X-ray diffraction results of the analysis of the corroded surfaces reveal a detect-able CuCl phase and an altered morphology when B is present. The protective effect of B was explained by magnetic forces that maintain the Cu2+ in the solution/metal interface for a longer time, hindering the arrival of the new corrosive agents, and leading to the formation of a CuCl phase, which may contribute to the rougher surface. The time-domain NMR method proved to be useful to study the effect of B in the corrosion of other metals or other corrosive liquid media when the reactions produce or consume paramagnetic ions.

Ano de publicação: 2022

Tipo de publicação: Artigo de periódico

Unidade: Embrapa Instrumentação

Palavras-chave: Copper corrosion, Magnetocorrosion, Time-domain NMR relaxometry