Tuning phase composition and morphology of calcium phosphate coatings on Ti6Al4V by pulse electrodeposition

This study investigates the influence of varying experimental parameters on the electrodeposition mechanism, phase composition, and morphology of calcium phosphate coatings synthesized by pulse electrodeposition on Ti6Al4V alloys. The objective is to optimize the pulse electrodeposition parameters to enhance the physicochemical properties of calcium phosphate coatings on Ti6Al4V alloys, aiming to improve bioactivity and osseointegration potential for biomedical applications. Cyclic voltammetry was used to elucidate the reaction mechanisms, while coatings were obtained under controlled pulsed potentials at two pH values (4.5 and 6.0) and three pulse ratios (ton/toff = 30/15, 60/30, and 120/60 seconds). The morphology, roughness, phase composition, and chemical structure of the coatings were characterized using scanning electron microscopy (SEM), confocal microscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results revealed that pH and pulse duration have a substantial impact on the local electrochemical environment, influencing the phase composition (hydroxyapatite vs. brushite), surface roughness, and porosity. Coating produced at pH of 6 exhibited predominantly hydroxyapatite phases, whereas lower pH values led to biphasic compositions. The thickness and roughness of the coating showed a direct dependence on pulse duration. These findings demonstrate the feasibility of tailoring calcium phosphate coatings through pulse electrodeposition for enhanced biomedical performance.