Electrodeposition and the properties of a Zn-Cotton nanocrystal composite coating

Abstract

The present work proposes the study of a composite zinc coating obtained through electrodeposition containing nanoparticles of a natural polymer of cotton nanocrystals. In this work, the effect of the addition of cotton nanocrystals on the morphology, structure, corrosion resistance, and hardness of the zinc coating is investigated. The effect of adding these particles on deposition efficiency is also investigated using scanning electron microscope (SEM), X-ray diffraction, roughness and Vicker microhardness measurements, mass loss tests, obtaining potentiodynamic polarization curves, and electrochemical impedance spectroscopy (EIS). Current density efficiency measures were also taken. It was found that the addition of the cotton nanocrystal in the deposition bath lead to the production of a coating with finer morphology and with less roughness compared to Zn coating obtained in the absence of the nanocrystal. However, it was found that the addition of cotton nanocrystal decreased the hardness of the coating. The results show that the addition of cotton nanocrystal increases the current efficiency and corrosion resistance of zinc coating in 0.5 mol/L NaCl solution, and this effect is more significant with the increase in the content of the nanocrystals. With the addition of 10% v/v of cotton nanocrystal the polarization resistance of the coating was improved up to 5-fold while its corrosion rate was reduced by up to 6-fold compared to the zinc coating without nanocrystals.