Oxide films characterization

SIMS Cluster Ion Characterization During Oxygen Adsorption and Oxidation. For heavy oxidation, that is essentially bulk oxide films, the oxidation state of the metal can be determined from the positive and negative SIMS intensity distributions (1 ). Though similar attempts have been made to characterize the nature of the surface during the early stages of oxygen interactions (14,15), we now know from the extensive information available from other techniques that such interpretations are incorrect. We use the by now well-characterized W(100)/O and Ni(100)/0 systems as examples. 

Tremiliosi-Eilho G, Jerkiewicz G, Conway BE. 1992. Characterization and significance of the sequence of stages of oxide film formation at platinum generated by strong anodic polarization. Langmuir 8 658-667. 

Mrad/h). Films were stored at -20° until analysis could be carried out. Oxidized films and derivatized, oxidized films were characterized by iodometry (reflux with Nal in isopropanol/acetic acid) and by transmission Fourier Transform (FT) IR (Perkin Elmer 1500), using the spectral subtraction technique (3, 14). Free radicals were measured by the electron spin resonance technique (e.s.r., Varian E4 spectrometer). 

The formation condition for PS can be best characterized by i-V curves. Figure 2 shows a typical i-V curve of silicon in a HF solution.56 At small anodic overpotentials the current increases exponentially with electrode potential. As the potential is increased, the current exhibits a peak and then remains at a relatively constant value. At potentials more positive than the current peak the surface is completely covered with an oxide film and the anodic reaction proceeds through the formation and dissolution of oxide, the rate of which depends strongly on HF concentration. Hydrogen evolution simultaneously occurs in the exponential region and its rate decreases with potential and almost ceases above the peak value. 

The passive film is composed of metal oxides which can be semiconductors or insulators. Then, the electron levels in the passive film are characterized by the conduction and valence bands. Here, we need to examine whether the band model can apply to a thin passive oxide film whose thickness is in the range of nanometers. The passive film has a two-dimensional periodic lattice structure on... 

Ruby, C. Fusy J. Genin, J-M.R. (1999) Preparation and characterization of cross oxide films deposited on MgO (100). Thin solid films. 352 22-28... 

Marino GEB, Nascente PAP, Biaggio SR, Rocha-Pilho RG, Bocchi N (2004) XPS characterization of anodic titanium oxide films grown in phosphate buffer solutions. Thin Solid Pilms 468 109-112... 

An in-situ characterization of the interface structure of the growing oxide film appears to be necessary for an appropriate modeling, but this is most difficult to achieve [B. Pieraggi, R. A. Rapp (1988)]. 

The initial surface composition of boiler tubing, prior to its installation will have an important impact on the amount and type of activated corrosion products in an aqueous reactor coolant. Consequently, the type of thermal pre-treatment the tubing undergoes, for example, for mechanical stress release,will affect the surface oxide film, and ultimately, the corrosion behavior. This particular work has been directed toward characterization of surface oxide films which form on Inconel 600 (nominal composition 77% Ni, 16% Cr, 7% Fe, — a tradename of Inco Metals Ltd., Toronto Canada) and Incoloy 800 (nominal composition 31% Ni, 19% Cr, 48% Fe 2% other, — a tradename of Inco Metals Ltd., Toronto, Canada) heated to temperatures of 500-600°C for periods of up to 1 minute in flowing argon. These are conditions equivalent to those experi enced by CANDU(CANadian Deuterium Uranium)ractor boiler hairpins during in situ stress relief. 

The vibrationally excited precursor AB/s/(fs) can decay not only via energy transfer to the bulk but also via a chemical transformation (desorption of B and reaction with the formation of D and C/s/). These chemical processes can be characterized by the chemical lifetime Tch, which can be estimated in the framework of the statistical RRKM theory (see, e.g., Refs. [50, 51]) using the reaction parameters of reagents B and A/s/, precursor AB/s/, and transition complexes determined based on the results of quantum-chemical calculations. Such estimates were performed for many reactions of interest for the growth of metal oxide films [20]. It appeared that in the wide temperature range... 

Lausmaa, J., Kasemo, B., Matsson, H., and Odelius, H., Multi-technique surface characterizations of oxide films on electropolished and anodically oxidized titanium App. Surf. Sci. 45, 189-200 (1990). 

The intensities of the integrated signals may be evaluated on the basis of well-characterized standards. Consequently ISS provides qualitative and quantitative information on the composition of the surface. Noble gas ions that penetrate the first layers of the surface are backscattered as neutrals, and thus may not pass the energy analyzer. As a consequence, only ions backscattered at the first atomic layer are detected and the method is sampling the outmost atomic layer. A soft sputter process by noble gas ions yields an ISS depth profile with atomic depth resolution. Therefore ISS has been applied to the study of very thin oxide films, as e.g. of passivated Fe/Cr alloys. This method may be applied in addition to XPS due to its high depth resolution. 

As is the case for most natural phenomena, oxide films often have a rapid initiation, a vigorous youthful growth period, a fruitful middle age, a declining later period and, finally, destruction. In this vein, we can list at least ten overlapping stages which may characterize an oxide film at one time or another during its lifetime. 

The metal oxides prepared by conventional baking or by the CVD method are, in general, chemically stable, crystalline materials, and show excellent mechanical, electrical, optical, and physical properties. Flexible porous gel films obtained by the surface sol-gel process are totally different. In this chapter, we described a new preparative method for ultrathin metal oxide films by stepwise adsorption of various metal alkoxides. We named this method the surface sol-gel process. Structural characterization of the gel films thus obtained, the electrical property, and formation of nano-composites with organic compounds, were also explained. The soft porous gel contains many active hydroxyl groups at the surface and interior of the film. This facilitates adsorption of organic compounds, and consequent preparation of ultrathin metal oxide/polymer nano-composite films and organization of functional small molecules. In the nano-composites, proper selection of polymer components leads to the design of new materials with unique electrical, optical, and chemi-... 

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