Biological activity and corrosion resistance of Ca-P/chitosan composite membrane on magnesium alloy

Calcium phosphate (Ca-P)/chitosan membranes were formed on AZ91 magnesium alloy coated MAO membrane by chemical deposition method. Various spectroscopic techniques, such as X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and inductively coupled plasma, were used to characterise the surface morphology, crystalline structures and chemical compositions. They show that the biological composite membrane is composed of tricalcium phosphate, dibasic calcium phosphate and hydroxyapatite. After adding chitosan, the physical properties of Ca-P membrane changed significantly. Electrochemical test and immersion test in simulated body fluid (SBF) were used to evaluate the corrosion resistance and biological activity. Results show that Ca-P/chitosan membranes increased the corrosion potential of the materials and decreased the corrosion current. Ca-P/chitosan membranes could reduce the biodegradation rate of magnesium alloy in SBF. Therefore, the corrosion resistance of magnesium alloy is improved.