The Role of defects which play in the process of functional degradation in environmental resisting properties of ceramic coatings

针对各种类型的材料的薄膜涂层已被用于保护基底表面免受腐蚀损害或为其添加许多功能。迄今为止，对TiN薄膜涂层的研究主要集中在力学性能和化学性能方面。因此，在这项研究中，基本性能，如CVD和PVD涂层的耐腐蚀特性的角度来看，在涂层的缺陷和涂层与基体之间的附着性能。研究了涂层功能退化过程中缺陷对涂层耐环境性能的影响。主要研究结果如下：（1）利用原子力显微镜（AFM）对TiN涂层在3%NaCl水溶液中的局部腐蚀过程进行了详细的微米级或微米级的观察，研究了TiN涂层的局部腐蚀过程。结果表明，局部腐蚀形貌与缺陷类型之间存在相关性。此外，缝隙腐蚀特性是由薄膜与基体之间的附着性能控制的。(2)本研究中所使用的TiN薄膜涂层是由两种不同类型的涂层方法，即等离子体CVD和动态离子混合（DIM）方法。利用原子力显微镜（AEM）研究了微米级和微米级铝合金在3%NaCl水溶液中的腐蚀缺陷形貌和局部腐蚀初期形貌。结果，根据涂覆方法，明显观察到缺陷类型和局部腐蚀形态的差异。(3)电化学原子力显微镜（AFM）可以在不同的电化学控制条件下对不同镀膜方法制备的TiN薄膜的缺陷类型和初始局部腐蚀过程进行原位观察。

Thin film coatings toward various types of materials have been used for protecting substrate surface from corrosion damages or adding a lot of functions to them. Till now the studies have been mainly conducted concerning mechanical and chemical properties of TiN thin film coating. Therefore in this study, basic properties such as corrosion-resisting characteristics of CVD and PVD coatings were investigated from the viewpoint of defect in coated layer and adhesion properties between coating and substrate. The roles of defects, which play in the process of functional degradation in environment resistant characteristics of coatings, were examined. And then, improvement in these characteristics of coatings by making better the adhesion state between coating and substrate is investigated.Results obtained are summarized as follows ;(1) Extremely initial stages of localized corrosion process in coated TiN thin film in 3%NaCl aqueous solution was investigated by detailed mum or urn orders observations using Atomic Force Microscope (AFM). As a result, it was observed that correlation between localized corrosion morphologies and type of defects. Moreover, crevice corrosion characteristics were controlled by the adhesion properties between thin film and substrate was recognized.(2) TiN thin film coatings used in this study were made by two different types of coating methods, that is, Plasma CVD and Dynamic Ion Mixing (DIM) method. Then, defect morphology and the initial stage of localized corrosion morphology of urn or mum orders in 3% NaCl aqueous solution was investigated by Atomic Force Microscope (AEM). As a result, difference in the types of defects and localized corrosion morphologies were dearly observed depending upon the coating methods.(3) Electrochemical AFM in-situ observation of the types of defects and initial localized corrosion process on TiN thin film made by different coating methods can be conducted under various electrochemically controlled conditions.