以硫酸和磷酸为电解液,工业纯钛为阳极,不锈钢为阴极,恒电流阳极氧化的方式在钛表面直接获得TiO2多孔氧化膜,经过500℃热处理,促进氧化膜由非晶体向晶体的转变.采用扫描电镜和X射线衍射对阳极氧化膜的形貌和结构进行了分析,研究了电流密度、电解液种类以及浓度对TiO2多孔氧化膜形态和晶型的影响,并探讨了其形成机理.结果表明,以磷酸为电解液时钛表面仅生成锐钛矿相的TiO2,而以硫酸为电解液时钛表面生成锐钛矿和金红石两种晶相的TiO2.
The TiO2 porous films were prepared directly on the surface of pure titanium by constant current anodic oxidation using sulphuric acid and phosphoric acid as electrolytes, pure titanium and stainless steel as anode and cathode respectively. Surface morphologies of the TiO2 porous films were observed by scanning electron microscope and crystal phases were analyzed by X-ray diffraction. The effects of the current density, the kinds and concentrations of electrolytes on the surface morphologies and crystalline phases of TiO2 porous films were investigated,and the forming mechanism of TiO2 porous films and its crystallization were discussed. The results show that the current density and electrolyte concentration are the two main factors effecting the surface morphologies and crystalline phases of the anodic oxidation films. The TiO2 porous films are transited from non-crystal to crystal by heat treatment at 500℃ for two hours. The anodic oxidation films only have anatase phase on the surface of pure titanium in the phosphoric acid,and the aperture sizes range from several hundred nanometers to several micrometers, whereas the anodic oxidation films have anatase phase and rutile phase on the surface of pure titanium in the sulphuric acid,and the aperture sizes range from 100 ~ 200 nm.