Porous and nanostructured TiO2 coatings with different Ca, P contents were prepared on titanium by plasma electrolytic oxidation (PEO) in a Ca and P containing electrolyte at different current densities. The surface morphologies and microstructure of the coatings were observed by scanning electron microscope (SEM). Phase compositions of the coatings were characterized using X-ray diffraction (XRD). Simulated body fluid (SBF) immersion tests were conducted to evaluate the apatite forming ability and bioactivity of coatings. The results reveal that the PEO coatings mainly consist of anatase and rutile phases, their surfaces exhibit grains of about 10-100 nm in size and pores less than 10 urn in diameter. The surface grains, coating thicknesses, surface roughness and Ca, P contents of the coatings all increase with the increase of the applied current density during PEO process. The as-prepared PEO coatings with high Ca and P contents could induce apatite formation after immersed in SBF for 14 d, indicating its good bioactivity. However, PEO coatings with low Ca and P contents or heat-treated coatings are bio-inert. The Ca, P contents of the PEO coatings and its crystallization state play key roles in inducing apatite formation in SBF.%采用等离子体电解氧化(PEO)技术,在纯钛基体上制备了具有多孔和纳米结构并含有不同钙磷含量的氧化钛涂层.采用扫描电子显微镜和X射线衍射仪研究了涂层的显微结构和相组成.采用模拟体液浸泡实验评价涂层的生物活性.研究结果表明:涂层主要由锐钛矿和金红石相组成,涂层表面孔径小于10μm,晶粒直径约10～100nm,且涂层表面晶粒、涂层厚度、表面粗糙度和涂层中的钙磷元素含量均随着PEO过程中电流密度的增大而增加.PEO涂层在模拟体液中浸泡14 d即能够诱导类骨磷灰石在其表面沉积,显示出良好的生物活性.涂层中的钙磷含量和结晶形态对其生物活性起关键作用.
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