A Case Study: Investigation of Untreated and Treated 304 Stainless Steel on Corrosion Behaviour

Abstract

A titanium coating on an iron-based metal surface significantly enhanced its resistance to localised corrosion. The research thoroughly investigated the microstructure and corrosion behaviour of both the untreated and treated 304 stainless steel substrates. The coating’s morphology was meticulously examined using scanning electron microscopy (SEM), while its chemical composition was determined via energy-dispersive X-ray spectroscopy (EDX). Electrochemical impedance spectroscopy (EIS) was employed in an open circuit potential experiment to evaluate the coating’s resistance to localised corrosion in an alkaline solution. SEM was again utilised to assess the coating’s morphologies and cross-sectional view. The result revealed that untreated samples showed small and large pits on the microstructure, while no pit was detected in treated samples. Only fine dimples and voids were observed for the treated sample. The treated sample exhibited superior corrosion resistance to the untreated sample with a corrosion rate of 0.002348 mm/year and 0.007109 mm/year, respectively. This is attributed to the presence of the coating for a treated sample with curing for 10 minutes. The corrosion rate value is still considered excellent and accepted for stainless steel because the corrosion rate penetration is below 1 mils per year (mpy).