Surface and interface analysis techniques are reviewed mainly about electron microscopy and surface analysis methods. The principal of the techniques, fundamental and preferable way of using them, some examples, and future prospects of them are presented.
At metal oxide (AO)-metal (M) interfaces, metal (M) atoms can make bonds with metal oxide through either oxygen (O) atoms or metal (A) atoms that composed of the oxide. Examples of the identification of an element at the interface in atomic level using photoelectron spectroscopy have been demonstrated for alumina, zinc oxide and cerium oxide. Software, which predicts interface bonding according to a method developed by the author, and which is open to public, is presented. It is demonstrated that the difference in the interface bonding species has great influence on the band offset, the energy difference between the Fermi level and the valence band in the band energy diagram. The observations of such difference in band offset using photoelectron spectroscopy are also provided.
The analysis techniques using X-ray have advantage in non-destructive analysis or in-situ observation of reaction due to its high transmissivity to materials. Utilization of synchrotron radiation expands the capability of X-ray analysis. Applications of three techniques using synchrotron radiation are introduced; hard X-ray photoemission spectroscopy, X-ray diffraction measurement controlling X-ray penetration depth, and in-situ X-ray diffraction measurement of reaction in water.
Fundamentals of an electrochemical impedance measurement were reviewed. The impedance characteristics under charge transfer control and under diffusion control, and their equivalent circuits are described. Analytical method using the Nyquist plot and the Bode plot for typical impedance spectra was explained. In addition, a change in impedance behavior for CPE (constant phase element) parameter, which is often used in equivalent circuit modeling and data fitting of electrochemical impedance data, was represented. In the latter of this paper, research reports for degradation estimation of steel materials used for infrastructure using an electrochemical impedance measurement were provided. The degradation of organic coated steels, the structure of thermally sprayed coating exposed to outdoors for a long term, and the corrosion performance of reinforcing steel bars in concrete were estimated by electrochemical impedance method.