Modification of degradation behavior of magnesium alloy by IBAD coating of calcium phosphate

In order to modify the degradation behavior of magnesium alloy, hydroxyapatite (Ca10(PO4)6(OH)2) coating is formed on magnesium alloy by ion-beam assisted deposition (IBAD) and heat treatment. The morphology, composition and phase structure of the coated samples were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy, respectively. The width of atomic mixed interface between the coating and substrate formed by IBAD was approximate 3 μm, which was measured by Auger electron spectroscopy. The hardness and elastic modulus of coating were measured with a depth-sensing nanoindenter system. The results of accelerated test (AT) of degradation indicate that the coatings can decrease degradation rate of original Mg alloy significantly.