Surface Characterization And Corrosion Resistance Of Ceramic Coating On The Surface Of Titanium By Micro-arc Oxidation

Objective The purpose of this study was to consider the efficacy for titanium implantmodification by micro-arc oxidation technology and supply experiment foundation for developingnew-style dental implant.Methods Ceramic coating was formed on titanium surface by using micro-arc oxidation. Themorphology, elemental composition and phase components of the films were studied by scanningelectron microscopy (SEM), energy dispersive spectrum (EDS), and X-ray diffraction (XRD),respectively. Roughness and contact angles were measured by profilemeter and contact angle meter,Corrosion resistance of titanium immersed in simulated body fluid was investigated by polarizationcurves and electrochemical impedance spectroscopy (EIS).Results About 10μm ceramic coating was formed on titanium surface with micro-arc oxidationand was made from O, Ti, Ca, P elements. On the surface, the coating was consisted of many volcanicmicroporous, about 0.1μm～5μm in diameter. XRD indicated that the phase components of the coatingcould be anatase and rutile mainly, otherwise hydroxyapatite and calcium phosphate hydrate were alsoinvestigated. The surface roughness of micro-arc oxidation specimens increased (P＜0.01), meanwhilecontact angles decreased. Electrochemical experiment revealed the self-corrosion potential andself-corrosion current density of titanium with micro-arc oxidation film were -0.255V and 0.80μA/cm~2respectively, while those of untreated titanium were -0.358V and 0.55μA/cm~2. EIS confirmed model ofequivalent circuits is reasonable.Conclusions1. Ceramic coating was formed on titanium surface by using micro-arc oxidation.2. Micro-arc oxidation film was made from O, Ti, Ca, P elements and 1.63 Ca/P ratio wassimilar to hydroxyapatite.3. Ceramic coating included anatase, rutile and hydroxy-apatite.4. Increased roughness and decreased contact angles on titanium surface by using micro-arcoxidation.5. In simulated body fluid, the corrosion resistance of specimens enhance significantly, inaddition, the microstructure of micro-arc oxidation film was the main reason of highcorrosion resistance.