Influence of glycine additive on corrosion and wear performance of electroplated trivalent chromium coating

The aim of this study is to evaluate the effect of various molar ratios of glycine to chromium salt (Gly : Cr) and different current densities on the corrosion and wear behaviors of Cr(III) electroplated coatings. The morphology and thickness of the coatings were investigated by scanning electron microscopy. The wear properties of the coatings were studied using pin on disk and hardness tests, while corrosion behavior of the coatings was identified using linear polarization, small amplitude cyclic voltammetry, and electrochemical impedance spectroscopy methods. By increasing the glycine concentration, a structure with low crack density was obtained. In all molar ratios, maximum thickness and current efficiency was observed at a current density of 150 mA·cm⁻². All the electrochemical methods had a consistent result, and maximum corrosion resistance of approximately 16000 Ω·cm² was obtained in the case of Gly : Cr = 3:1 and current density of 200 mA·cm⁻².