Effect of hydrogen peroxide concentration on the nanostructure of hydroxyapatite coatings via ultrasonic-assisted electrodeposition

Abstract

Hydroxyapatite (HA) coating is prepared by ultrasonic-assisted electrodeposition from the electrolytes containing hydrogen peroxide (H2O2). Effects of H2O2 concentrations (0, 0.5, 2.0, 4.0 mL/L) on the morphology, chemical bonds, crystallinity and roughness of the HA coatings are investigated. The results show that the HA coating via ultrasonic-assisted electrodeposition is spindle-like in the absence of H2O2, but becomes flake-like and wrinkle-like morphology after adding different concentrations of H2O2 into the electrolyte. The SEM image of HA coating at half of the deposition time (i.e. 30 min) reveals the transition from spindle-like to wrinkle-like. TEM image shows that wrinkle-like HA coating electrodeposited at 4.0 mL/L H2O2 is also found with spindle-like HA crystal nanostructure. The influencing mechanism of H2O2 on the HA coating nanostructure is also proposed. This study provides a new idea for the preparation of hydroxyapatite electrodeposited coatings.