Influence of blackberry leaf extract on the copper corrosion behaviour in 0.5 M NaCl

[Display omitted] •The blackberry leaf extract acts as mixed copper corrosion inhibitor in 0.5 M NaCl.•Determination of the extract composition and functional groups was performed.•The inhibitor adsorption prevents the corrosive effect of chloride.•The inhibitor efficiency was determined by applying the PP, EFM and EIS methods. The research presented in this paper is focused on blackberry leaf extract (BLE) as a environmentally friendly corrosion inhibitor for copper in 0.5 M NaCl. The caffeic acid, quercetin-3-O-glucoside and kaempferol-3-O-glucoside were identified in BLE by using high-performance liquid chromatography (HPLC-DAD). The BLE functional groups were identified (ATR-FTIR). The electrochemical methods (potentiodynamic polarization, electrochemical frequency modulation and electrochemical impedance spectroscopy) show that BLE acts as a mixed type of inhibitor (max. IE is 97.19 %). The corrosion process is controlled by diffusion (BLE lower than 15 g/L) and charge transfer (15 g/L BLE).