Effect of composition and microstructure of duplex stainless steel on adsorption behaviour and efficiency of corrosion inhibitors in 4 molar hydrochloric acid. Part I: Standard DSS 2205

•Variation in elemental composition on 6 batches of duplex stainless steel 2205 results in different uninhibited and inhibited corrosion rate.•The higher the Ni content, Ni/Cr ratio or austenite content, the lower is the weight loss.•Use of higher inhibitor dosage (20 mM) eliminates such dependence of weight loss on variation in the elemental compositions.•Cationic inhibitor preferentially adsorbs on ferrite phase (carbon concentration on ferrite phase is three time that on austenite phase measured by SEM-EDX).