Establishment of Ceramic Coating System for Improving Resisting Function of Thin Film Coating from the Environmental Attack

针对金属和有机化合物等各种材料的薄膜涂层已被用于保护基材表面免受恶劣环境的影响或为其增加许多功能。然而，涂层从一开始就存在纳米缺陷和裂纹。在实际环境中，腐蚀溶液通过涂层的纳米缺陷进入基材，从而产生降解。因此，从(a)通过注入N^+离子提高基体金属的耐腐蚀性，(b)通过动态离子混合（DIM）方法优化薄膜形成条件来提高附着强度，(c)通过涂层TiO_2膜的光催化作用来保护薄膜涂层试样免受腐蚀等方面进行了各种研究。所得结果总结如下：(1)通过划痕试验研究了等离子体CVD涂层TiN膜的粘附特性。更重要的是，通过研究TiN薄膜形成的温度条件与划痕试验得到的Lc临界载荷之间的关系，评价TiN薄膜与衬底的粘接强度。同时，通过对基材粘附强度的依赖性评价，明确了CPCD试验对不同膜厚和粘附强度的TiN薄膜缺陷率评价的适用范围。此外，还讨论了对CPCD测试方法的改进，以避免对薄膜缺陷的过高估计。(2)为了更好地了解薄膜涂层局部腐蚀过程与缺陷形貌之间的关系，需要在水溶液中进行现场观察并结合电化学测量。因此，利用作者新建立的电化学原子力显微镜（EAFM）对3% NaCl水溶液中缺陷形貌和nm或μm级局部腐蚀进行了原位观察。(3)采用离子束混合法制备了304不锈钢表面的TiO_2薄膜。因此，离子束混合法制备的TiO_2薄膜具有优异的粘接性能和梯度结构。然后用XRD和ESCA对薄膜的组成和晶体结构进行了表征。并证实了0.15mm厚的TiO_2薄膜在0.3wt% NaCl水溶液中具有阴极保护性能。少

Thin film coatings toward various types of materials such as metal and organic compound have been used for protecting substrate surface from harsh environment or adding a lot of functions to them. However, nanometric defects and cracks were always existed in coated thin film from the initial stage. In actual environment, degradation was generated as a result of the corrosive solution going into substrate through the nanometric defect of coating. Therefore, various investigations were conducted from the view points of (a) improvement of corrosion resistance of substrate metal through N^+ ion implantation, (b) Improvement of adhesion strength by optimizing thin film formation condition by Dynamic Ion Mixing (DIM) method and (c) protection of thin film coated specimen from corrosion by photo-catalytic effect of coated TiO_2 film.Results obtained are summarized as follows ;(1) The adhesion characteristic of TiN films, which was coated by plasma CVD, was investigated by the scratch test. Th … More en, through investigating the relationship between temperature condition of TiN film formation and critical load of Lc obtained by scratch test, the adhesive strength between TiN film and substrate was evaluated. Also, through evaluating the substrate materials dependency upon adhesive strength, the applicable range of the CPCD test was made clear for the defect ratio evaluation of TiN films with various film thickness and adhesion strength. In addition, some improvements in CPCD test method for avoiding the overestimation of defect in film were discussed.(2) Because of the better understanding of correlation between localized corrosion progress and defect morphology of thin film coating, in situ observation in aqueous solution together with electrochemical measurement was needed. Therefore, in situ observation of defect morphology and nm or μm orders localized corrosion generated in 3% NaCl aqueous solution was conducted by Electrochemical Atomic Force Microscopy (EAFM) newly established by present authors.(3) Formation and characterization of TiO_2 thin film made on 304 stainless steel by Ion-beam-mixing method were conducted. Therefore, TiO_2 thin film made by Ion-beam-mixing method have superior adhesive characteristics and graded microstructure. Then, examination of the compositions and crystal structure of deposited thin films were conducted by XRD and ESCA.And also, it was confirmed that the 0.15mm thick TiO_2 thin film could have cathodic protection performance in 0.3wt% NaCl aqueous solution at room temperature. Less