Preparation of Nano TiO_2-V_2O_5 Composite Coating and Its Functions in Corrosion Protection of Metals
- 化学化工－已发表论文 
采用溶胶-凝胶法和浸渍提拉技术在316L不锈钢表面构筑纳米TiO2薄膜和“夹心”式TiO2-V2O5复合薄膜(TiO2/TiO2-V2O5/TiO2),应用AFM和XRD表征膜的形貌及纳米颗粒的晶型.结合光、电化学方法测试了复合膜在0.5mol·L-1NaCl溶液(pH=4.6)中暗态或紫外照射条件下的防腐蚀性能.结果表明,TiO2/TiO2-V2O5/TiO2复合膜具有双重保护功能,即在紫外光照下可以起到光生阴极保护的作用,特别是当停止光照后,光生电位仍可维持在较低的电位长达6h以上.同时作为表面阻挡层,可显著提高金属的耐腐蚀性.Using sol-gel method and dip-coating process,TiO2 and sandwiched TiO2-V2O5 composite films (TiO2 / TiO2-V2O5 / TiO2) have been used to coat the surface of 316L stainless steel. The morphology and structure of the films have been analyzed by AFM and XRD. The anticorrosion properties of the composite films have been stud-ied under dark condition by electrochemical methods. The performance of photogenerated cathodic protection of the composite coatings has been measured in 0.5 mol·L-1 NaCl solution(pH=4.6) by combining photoelectrochem- ical system with corrosion electrochemical system under UV illumination. The results show a significant dual pro-tective performance for the composite films. Under UV illumination the photo-generated cathodic protection is ac-tive,and after the UV light is shut off, it takes about 6 hours for the photogenerated potential to shift from -0.25 V to -0.14 V, which implies a possibility to remain a cathodic protection of metal even in the dark condition. Fur-thermore,under the dark condition the sandwiched TiO2 / TiO2-V2O5 / TiO2 composite coatings as excellent barrier layers are able to provide a protection for the 316L in a corrosive environment.