Stainless steel corrosion resistance in 0.5 m h2so4 using cassia fistula extract

Abstract

A study of the corrosion behavior of stainless steel (SS) in 0.5 M sulphuric acid using Cassia fistula leaf extract (CFLE) at 30 °C was carried out. The study was conducted by taking the SS samples, in inhibited and uninhibited solutions through linear sweep voltammetry tests, and then subjecting the recorded data from the experiment to analysis, to yield the surface coverage, inhibitor efficiency, inhibition mechanism and adsorption model. The analysed data showed that inhibitor efficiency ranged from 98.59 to 95.25% at 2 and 8 g/L respectively. Surface coverage data for the experiment fitted well to the Langmuir model with a separation factor parameter showing favourable adsorption. Inhibitor adsorption was spontaneous showing overriding physical adsorption, while an anodic inhibition mechanism was displayed. CFLE promoted the overriding influence of the chromium oxide passive film on the SS metal surface to forestall the aggressive effect of sulphuric acid.