In order to enhance the research work on electrochemical corrosion, five corrosion systems have been selected to study by scanning tunneling microscopy, spectrum analysis, electrochemical measurement and some physical technologies in microscope. The morphologies of corrosion interface in those corrosion systems have been observed by STM. The composition, structure and other physical characteristics of those interfaces have been analyzed by spectrum analysis and some physical technologies. The relationship between the characteristic of interface in microscope and the corrosion mode in microscope has been discussed. The results are shown as follows: 1. The atomic structure of FeNiSiB amorphous alloy has been observed by STM. The structure of this amorphous alloy can be described by Bernal model. It means that this alloy is made up by Bernal polyhedron at first, this smallest particulate matter piles up together to form bigger particle and then to form the amorphous alloy in the end. The surface of this alloy can be described by factual dimension. This material has special corrosion behavior because of its special structure. The smallest structure that takes part in the corrosion reaction in this alloy is Bernal polyhedron so that the general corrosion occurs on amorphous alloy in the air and in the sulfuric acid solution. 2. The corrosion process of FeNiSiB amorphous alloy has been observed in 0.03 mol/L H_2SO_4 by STM in situ. In different period, the elements that affect the corrosion process are not same. At the beginning, the machining process plays a big role in the surface dissolving, and then, the dissolution process is decided by the structure of alloy. General corrosion can be described as that any part of the surface will be anodic region or cathodic region in different corrosion period. The harmonious development of this process led to the general corrosion mode in macroscope. 3. The negative difference effect (NDE) phenomenon of magnesium has been studied by electrochemical measurement and STM. After observing the morphology characteristics on magnesium by STM in nanoscale, the new "Partially Protective Film" mechanism is proposed to explain the NDE phenomena. The are may oxide pieces which do not bulk up on the magnesium surface and the magnesium will dissolve under the defect of oxide pieces when the anodic potential or current are applied on the electrode. It shows that the possibility and the degree of NDE are decided by the structure of oxide on the magnesium electrode . 4. The relationship between the existing form and inhibiting behavior of dodecylamine(DDA) on amorphous alloy has been studied by electrochemical measurement, physical test and scanning tunneling microscopy. The experiment shows that there are different relationships between the inhibitor concentration and inhibition efficiency in different concentration scale. During 1ppm～100ppm concentration scale, the inhibition efficiency increase with the inhibitor concentration steeply, but the increase tendency of inhibition efficiency lowers during 100ppm～1000 ppm concentration scale. The adsorption isotherm fumula fitting results show that only one DDA molecular layer adsorbs on amorphous alloy during 1ppm～100ppm concentration scale without any effect from the nearby inhibitor molecules, but during 100ppm～1000ppm, the force between the nearby inhibitor molecules decide the adsorption form. The result form STM and conductivity test recover that the micelle has been formed when the concentration comes to 23ppm, the protection efficiency of DDA is limited due to the forming of micelle. The typical structures of micelle have been observed by STM and the process of micelle forming was proposed in the end. 5. The morphology of the protection film of AMT formed on bronze has been observed by scanning tunneling microscopy in Angstrom scale. There are five ellipse units join together to form linear structure. Many linear structures make up the protection film to prevent corrosion process of bronze. After analysis the reactivity of AMT with Cu ion by XPS, XAES and IR, the conclusion has been gotten as following: Cu ions dissolving from bronze combined with AMT, and then, the complex compound deposit on the bronze to form the protection film.
修改评论