Ellipsometry has been used to study the growth of anodic films on superpure aluminum in sodium hydroxide of concentration range 0.1-4M. The ellipsometer used was a self-nulling type, and all experiments were performed in situ at a constant wavelength of 632.8 nm. The results are explained by the growth and dissolution of anodic films that are duplex in nature. During the dissolution process, at certain potentials, a highly reproducible transient effect in the optical signal is seen. This effect has been related to roughening of the underlying aluminum substrate, followed by subsequent smoothing upon completion of the dissolution process. The latter is indicated by the optical signal returning close to its initial value prior to film growth. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 138.251.14.35 Downloaded on 2015-03-13 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 138.251.14.35 Downloaded on 2015-03-13 to IP ABSTRACTThe cyclic voltammograms in 98% H~SO4 were measured on the mesophase-pitch-based carbon fibers heat-treated at various temperatures. They showed a marked dependence on the heat-treatment temperature of the carbon fibers. The electrochemical formation of graphite-sulfuric acid intercalation compounds was confirmed by x-ray diffraction. The change of graphite layer planes in the carbon fibers due to electrolysis was examined by Raman spectra.

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Die ellipsometrische Untersuchung des Oxid?lmwachstums auf hochreinem Al in 0.1 ‐4 M NaOH erfolgt in situ bei einer konstanten Wellenlänge von 632.8 nm.

Cyclisch voltammetrische, Photostrom‐sp‐ektroskopische sowie Kapazitätsmessungen zeigen, daß durch die Cu‐Oxidation beim Vorwärts‐sweep des cyclischen Voltammogramms anfangs eine p‐leitende (′u3O‐Schicht gebildet wird, und daß die Dicke der Schicht beim Rück‐sweep zunimmt, da eine Deckschicht aus Cu(OH)3 oder CuO zu CugO reduziert wird.

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