Use of natural extracts as corrosion inhibitors for AISI 304 steel

Abstract

The research is based on the study of the effect of non-toxic compounds on the environment and renewable natural resources, using them as environmentally safe corrosion inhibitors for AISI 304 steel in 0.1 mol /L. The evaluation of the corrosion protection was done with the immersion of steel plates of aqueous and ethanolic extracts of mate and green tea. The corrosion potential was determined using a saturated calomel electrode as reference. In the absence of inhibitors in a time of 60 minutes, the control test showed corrosion potential equal to -158 mV / ECS. However, in the presence of mate aqueous extract, the Ecorr was - 138 mV/ECS and -149 mV / ECS for the aqueous extract of green tea. The ethanolic extracts of mate and green tea presented potential corrosion results of -58 mV / ECS and -143 mV / ECS, respectively. Only the ethanolic extract of mate presented significative results in the inhibition of the corrosive process in the metal study, presenting meaningful values ​​of Eca before and after inhibitor treatment statistically different by pareid sample t-test. Thus, the ethanolic extract of mate grass presents potential use as a green corrosion inhibitor.