Microstructure and bioactivity of Ca, P and Sr doped TiO2 coating formed on porous titanium by micro-arc oxidation

In the present study bioactive coatings enriched with micro-pores and Ca P Sr elements were formed on pore walls of porous titanium by micro-arc oxidation (MAO) It is found that pore size plays a significant role on the MAO treatment of porous titanium For samples with pore size smaller than 90 mu m whatever applied voltage and treatment time were employed MAO coatings were formed only in the near surface region As to the sample with average pore size of 150 mu m MAO coatings were formed on both outer and inner pore walls throughout the depth Compared with the untreated one the specific surface area dramatically Increased about 460 times Further studies found that pore size thickness and amounts of 0 Ca P and Sr elements of the coating on the outer pore walls were obviously higher than those on the Inner pore walls Additionally the coating on the outer pore walls was composed of anatase and rutile TiO2 and other complex Ca P Sr phases in comparison with anatase TiO2 formed on the inner pore walls In spite of the distinct features of coatings on the different locations of pore walls MAO-treated porous titanium overall showed a good apatite inducing ability (C) 2010 Elsevier B V All rights reserved