Effect of Growing Conditions and Post Treatments on Calcium Phosphate Films Obtained by Electrode Position

Abstract

The effect of growing conditions and post treatments in electrodeposited calcium phosphate films on 316 L stainless steel is presented. The concentration and pH of electrolyte solution and the potential values for the electrodeposition process were determined based on a study of cyclic voltammetry curves. The electrolyte concentration was fixed at 0.025 M ((NH4) H2PO4) and 0.042 M (Ca(NO3)2.4H2O), choosing a pH = 5 as the better condition for the films deposition. In addition, the electrolyte temperature was varied between room temperature and 60°C to determine the influence of this parameter on the deposited films. Films were characterized using Fourier Transform Infrared Spectroscopy, X-ray diffraction and Scanning electron microscopy equipped with energy dispersive spectroscopy. The as deposited films at -1.2 V and -1.7 V exhibit the dicalcium phosphate dihydrate phase (Brushite) while thermal post treatment favor the formation of octacalcium phosphate in amorphous phase, and basic treatment tend to produce the Hydroxyapatite phase. The suggested mechanism for the HAp phase formation, after the basic treatment, consists in providing the necessary OH- groups to complete the synthesis process.