Corrosion inhibition effect of arabic gum on Cu-WC nanocomposite coating synthesized by electrodeposition technology

Nanostructured Cu-WC composite coatings were electrodeposited by co-deposition process onto pretreated steel substrate from an acidic sulfate electrolyte bath containing various amount of dispersed WC powder. The analysis by scanning electron microscopy shows those Cu-WC composite coatings containing cracks and random distribution of the oval-shaped WC particles. The X-ray diffraction (XRD) reveals that the structure of Cu-WC coatings is controlled by the WC powder amounts in the electrolyte baths. The average crystallite size was calculated by use X-ray diffraction analysis and its increasing is proportional to the enhancement of WC solid particles amount. The crystallite structure was fcc for electrodeposited Cu-WC nanocomposite coatings. The potentiodynamic polarization and electrochemical impedance spectroscopic studies reveal that grain refinement offers the best corrosion resistance. Arabic gum shows that it is an anodic inhibitor with high inhibitor efficiency reaches 70.95%. IR spectroscopy analysis shows several functional groups responsible for high inhibitor efficiency. Highlights Cu-WC coatings were electrodeposited with varying WC content onto steel substrates. SEM and XRD showed random WC distribution and fcc structure with increasing grain size. 10 g/L WC coating had the best corrosion resistance in 3.5% NaCl. Arabic gum improved corrosion resistance, acting as an effective anodic inhibitor. EIS confirmed max inhibitor efficiency of 70.95% at 25 g/L WC with Arabic gum.