纳米TiO2/SnO2涂层制备与光阴极保护性能

采用溶胶凝胶法与浸渍提拉技术在304不锈钢表面上制备了纳米TiO2/SnO2叠层涂层。用扫描电子显微镜(SEM)，X射线衍射(XRD），X射线光电子能谱(XPS)对涂层表面形貌、晶体结构与组成进行了表征。通过测量稳定电位方法研究了涂层的光电化学性能和对不锈钢的光阴极保护特性。结果表明，所制备的纳米TiO2/SnO2叠层涂层表面连续、均匀致密；涂层中的TiO2为锐钛矿型，颗粒呈球形，平均直径约为35nm，SnO2为金红石型；涂层表面与内层均由Ti、Sn、O、C四种元素组成。纳米TiO2表面层与纳米SnO2中间层分别浸渍提拉4次制得的叠层涂层，紫外光照的光电化学效应、储存电子性能与光阴极保护作用最好，紫外光照1h的延时阴极保护作用可达7h。通过研究分析,提出了纳米TiO2/SnO2叠层涂层的光阴极保护作用机理。

Preparation and Photocathode protection properties of nano-TiO2/ SnO2 coatings

By the sol - gel method and dip-coating process, nano-TiO2/SnO2 bilayer coatings were prepared on conducting 304 stainless steel substrates. Surface morphology structure and composition of the as-prepared TiO2/SnO2 coatings were characterized by SEM, XRD and XPS. The performances of photoelectricchemical and photocathode protection for 304 stainless steel were studied by measuring the steady potential of the bilayer coatings. The results show that the surface of the nano-TiO2/SnO2 bilayer coatings is uniform and compact. The bilayer coatings are composed of TiO2 in anatase and SnO2 in rutile and the particles are average in size of 35 nm.. Surface and inner of the bilayer coatings are composed of Ti, Sn, C and O elements. The results of electrochemical measurements show that the nano-TiO2/SnO2 coatings prepared by dipping 4 times for TiO2 coatings and SnO2 coatings respectively have most excellent photo-electrochemical properties and store Charges properties. It is indicated that the bilayer coatings were irradiated by UV illumination for 1 h and provided a cathodic protection for 7 h. In the paper, a new photocathodic protection mechanism of nano-TiO2/SnO2 bilayer coatings was put forward.