Micro-arc oxidation of β-titanium alloy: Structural characterization and osteoblast compatibility

The beta-titanium alloys have recently become important in bone implant applications. In this study, micro-arc oxidation (MAO) was used to modify the surface of beta-titanium alloy (Ti-13Cr-3Al-1Fe) using NaH2PO4 solution as an electrolyte. The microstructure of the oxidized layer as a function of the applied voltage and treatment time were investigated. The cellular adhesion, proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 pre-osteoblast were measured to reveal the cell compatibility of the treated specimens. The experimental results show that microstructure of the oxidized layer can be greatly affected by the discharge voltage and treatment time during MAO treatment as alpha-titanium metal and alpha + beta titanium are. The oxidized layer can gradually increase its thickness, pore size and surface roughness as a function of the discharge voltage and treatment time, which at the same time increases the rutile phase constituent. The osteoblast cell compatibility presented by the treated specimens is increased but less sensitive to the process parameters, even though the associated difference in morphology and crystalline form are found to be tremendous. (C) 2009 Elsevier B.V. All rights reserved.