铝基体上氧化铝／二氧化钛复合膜的形貌和结构研究

Morphology and structure of alumina/titania composite films on surface of aluminum

二氧化钛是一类具有高光催化活性的功能性材料，在能源、环保、卫生保健等领域有着重要的应用价值．利用阳极氧化和电沉积的方法在铝基体上制备了氧化铝／二氧化钛复合膜，通过XRD、TG／DSC、SEM、EDS、XPS等分析手段对复合膜的形貌和结构进行了表征，并对复合膜的形成过程予以阐述．结果表明，电沉积得到的TiO2为非晶态，随热处理温度的升高，TiO2向晶态转变。热分析结果确定TiO2由无定型结构向锐钛矿结构转变的温度约为425℃。TiO2分布于氧化铝膜的表面及微孔内部，随电沉积时间的增加，TiO2的含量增大，复合膜表面趋于出现裂纹缺陷。复合膜表面主要由Ti、O两种元素构成，同时存在较少量的Al、S、K等元素，其中Ti元素全部以TiO2的形式存在．铝阳极氧化膜表面的TiO2是通过交流电沉积过程中的阴极反应生成并沉积于氧化铝的表面及微孔内部，随沉积时间的延长，放电通道和氧化铝膜的溶解作用加剧，复合膜表面将呈现网状裂纹形貌。

As a kind of functional material, titania with high photocatalytic activity can be widely used in fields of energy, environmental protection, health care etc. In this paper, alumina/titania composite films were prepared on surface of aluminum by anodic oxidation and electrodeposition. The morphology and the structure of the composite films were characterized by XRD, TG/DSC, SEM, EDS, XPS methods and the formation process of the films was also discussed. The results show that electrodeposited TiO2 is amorphous and its structural transition will happen with the increasing of its heat-treatment temperature. The transition temperature from amorphous TiO2 to anatase is about 425℃ which were confirmed by thermal analysis. TiO2 exits on the surface and in the micropores of the aluminum anodic oxidation film. With the expansion of the dectrodepositing time, the content of TiO2 increases and cracks trends to appear on the surface of composite films. The surface element of the films mainly consists of Ti and O. The dement Ti exits all in type of TiO2 and other elements such as Al, S, K are also found but exit in minute quantity. TiO2 are created and deposited on the surface and in the micropores of alumina through the cathode reaction during AC electrodeposition. The effect of discharge channels and films dissolution will be enlarged with the expansion of electrodepositing time, and then a netlike cracks morphology will also be showed.