Oxidation Of Ti6Al4V Alloy And Its Biotribological Properties

Ti6Al4V alloy, with good corrosion resistance, mechanical properties andbiocompatibility, has been widely used in the biomedical field. Titanium oxide layer on thesurface of Ti6Al4V alloy were prepared by oxidation to improve friction and wearproperties of titanium alloy, providing a theoretical basis for modification of titanium alloy.Then the surface morphology, composition, mechanical properties, Electrochemicalproperties and biological properties were investigated.As temperature increases, the thicker oxide layer is formed, the greater stress betweensubstrate and oxide layer produced, eventually lead to the whole spalling of the oxide layer.As oxygen content increases, oxide layer get thicker and spalling area get larger. With theincrease of temperature and oxygen content, the microhardness of polished surface increaseat first then decreased, and the maximum microhardness value reach901HV and the nano-hardness value is14.82GPa at900℃and O240%vt, increased by1.82times and1.8timesseparately; while nano-hardness of oxygen diffusion layer formed at700℃is20.11GPa,increased by2.8times, conforming that an oxygen diffusion layer with good mechanicalproperties was formed on the surface of Ti6Al4V alloy.The corrosion current density increase by2.5to7.1times for Ti6Al4V alloy afteroxidizing at different temperature, and increase by1.2to4.3times after oxidizing atdifferent oxygen content, but the corrosion depth for oxidized Ti6Al4V alloy is0.0009~0.0018mm per year, indicating that the oxidized titanium alloy has good corrosionresistance.The oxygen diffusion layer improved the hardness of Ti6Al4V alloy, reduced adhesionin the process of friction and wear, reduced the friction coefficient of friction, and greatlyimproved the wear resistance of Ti6Al4V alloy. The wear rate was1.67×10-11kgN-1m-1after oxidizing at700℃and1.23×10-11kgN-1m-1after oxidizing at900℃, the wear rateis reduced by more than90%, suggesting an excellent resistance to wear performance.All the evidence indicated that oxygen diffusion layer, with good mechanicalproperties, good corrosion resistance and excellent wear resistance, were prepared on thesurface of titanium alloy by oxidation.