Characterization of electrodeposited calcium phosphate coatings by complementary scanning electron microscopy and scanning-transmission electron microscopy associated to X-ray microanalysis

The results showed that at 2 mA/cm2 current density, the coating is composed of an octacalcium phosphate: Ca8H2(PO4)6 and its amorphous phase called OCPam. At 5 mA/cm2, the coating is a mix of calcium deficient hydroxyapatite (Ca-def HAP): Ca10 − x(HPO4)x(PO4)6 − x(OH)2 − x with 0 < × ≤ 2 and its amorphous phase called Ca-def HAPam. And, at 10 mA/cm2, the coating is mainly composed of an amorphous phase of Ca-def HAPam. Furthermore, cathodic reaction mechanisms of electrolytic CaP coatings on Ti6Al4V are proposed to explain the different kinds of calcium phosphate obtained.