Abstract

The objective of this work was to study the galvanic corrosion of AISI 1020 carbon steel induced by the presence of copper sulfide mineral by electrochemical techniques using a home-made electrode with copper concentrate and a carbon steel working electrodes. The concentrate electrode as a film attached on a supportive media was prepared rubbing the surface tip of a graphite/wax electrode against dried powdered mineral. The graphite/wax electrode was a plastic cylinder with a cavity filled with a supportive media and metal fittings for electrical connections to the potentiostat (bare electrode). The supportive media was a 1.3:1 mixture of candle wax and pencil graphite respectively, which is a good electrical conductor. The carbon steel working electrode was prepared from a carbon steel disk embedded in a Teflon cylinder. A polarization curve from – 1100 a 1600 mV SHE using a graphite/wax electrode without film mineral indicated the occurrence of the main electrochemical reactions of hydrogen and oxygen evolution. In between these two reactions no significant redox activity was observed. This feature is very important to restrict the effect of interfering possible redox reactions of the particle support. The galvanic corrosion current density of steel induced by concentrate was achieved by superimposing individual concentrate and carbon steel polarization curves, both in contact with the same working aqueous solution. The main findings of this work are: a). –This technique allows the determination of electrochemical features of ground mineral. This is important where massive samples are not available. b). - The support for ground mineral exhibit ideal electrochemical features, c). - Concentrate induced galvanic corrosion on carbon steel in chloride solutions at ambient conditions was corroborated.