Anodized films on aluminum formed in sodium hydroxide bath containing hydrogen peroxide were investigated by X-Ray photoelectron spectroscopy (ESCA) and X-Ray diffraction. Electron binding energies between Al and O in anodized films formed at various electrolytic conditions were measured by ESCA. Metallic aluminum and aluminum (III) were observed in the films which anodized for 3 seconds but aluminum (III) were only observed after anodized for additional few seconds in the same anodizing bath at 40 voltage. By this results, it was suggested that anodized films were formed about 30Å by anodizing for 7 seconds. It was observed that amount of oxygen atoms due to hydroxide in the films for 3 seconds anodizing were increased and that of oxide were also increased by 7 seconds anodizing. X-ray diffraction patterns showed that a transition to αAl₂O₃ occured at about 900°C by heating and its temperature was lower than that of sulfuric acid anodized films. Hydrates of the films were obtained at lower temperature than sulfuric acid anodized films by the hydrothermal treatment.

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The purpose of this study is to compare the aluminum anodic oxide film anodized in sulfuric acid bath (DC 15V) with preanodized and electrolytically colored film (NiSO₄-H₃BO₃ bath, AC 15V) in respect to barrier layer thicknesses and corrosion resistance. Examinations have been carried out referring to (1) interfacial impedance diagrams and barrier layer thickness measured by Hunter's method, (2) TEM observations of the cross section of films and (3) potentiostatic polarization curves in a 1M sodium chloride solution, and dipping test in corrosive solutions. The results obtained are summarized as follows: (1) The interfacial impedance values of colored films were greater than those of uncolored films. The barrier layer thicknesses measured by Hunter's method were also in the order. (2) TEM observations revealed that the barrier layer thickness was more than twice as large as the initial thickness during AC electrolytic coloring. (3) The anodic currents caused by the pitting corrosion for the colored films were smaller than those of the uncolored ones. In dipping test, the colored films showed high resistance to pitting corrosion. The results of above examinations reveal that the electrolytically colored films were definitely more resistant to corrosion than the anodic films and this is due to the thickend barrier layer of the former films.

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Methods for precipitating uncomplexed zinc ions in an industrial wastewater from electroplating plants were investigated to obtain a precipitate favorable for electrolytical recovery of the metal, in which the sludge of zinc is supplied to the anode compartment of a diaphragm cell. Sodium hydroxide or sodium hydrogen carbonate was added to a zinc sulfate solution to form colloidal white precipitates. The ageing of the precipitates led to the gradual (quicker on warming) formation of a crystalline ZnO or Zn(CO_3)0.4(OH)_1.2. These crystallines had outstanding filtration rates and low contents of water (40% or less, as filtrated). The residual zinc ion concentration was lowered to less than 1mg/l in these cases.

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Ni-P, Co-P, and Ni-Co-P alloys (0≤P≤16wt%) were electrodeposited from Watts-type plating bath containing phosphorous acid. Effects of bath temperature, current density, content of phosphorous acid in the bath, and molar ratio of metal ions in the bath on the deposition rate and the composition of the deposited alloys were studied. The relation between Vicker's hardness and phosphorous content in the deposited Ni-P and Co-P alloys were also discussed. Moreover, for better understandings of the conformation or the nature of the chemical state of phosphorous, its properties and stability in the deposited Co-P alloys, the differential scanning calorimetry, the small angle X-ray scattering, and the P-K_β X-ray spectroscopy were measured on the alloys. The results are summerized as follows; (1) The deposition rate and composition of the deposited alloys are greatly influenced by the plating conditions, that is, temperature of the bath, current density, and composition of electrolytes in the bath. (2) The Ni-P, Co-P, and Ni-P, Co-P deposited alloys containing more than 5 wt% phosphorous exhibited the hardness of 600-800Hv. (3) Phosphorous in the Co-P alloys as deposited is bonded to cobalt by metallic bond, and it is suggested that phosphorous in the alloy is neither at the elementary state (red or white) nor constitutes stoichiometric cobalt-phosphides such as CoP, Co_1.6 P, and that the deposits are at the state of a super-saturated solid-solution of phosphorous in hcp Co (P<-5wt%) and an amorphous solid (P>-5wt%).

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The influences of Al³⁺ ion on the nickel deposition from nickel-aluminum ammonium sulfate bath (Ni²⁺ 0.15mol/l, Al³⁺ 0.15mol/l) containing citric acid were studied by means of galvanostatic/potentiostatic electrolysis, pH titration, and cathode polarization methods with respect to the feasibility of Ni-Al codeposition. If the amount of citric acid added was less than 30g/l and powdery or peeling deposits including aluminum were obtained at pH3, but when added citric acid was more than 30g/l, stable Al-citrate complexes were formed and uniform bright nickel deposits without containing aluminum were deposited. Cathode polarization curves were found to shift at a current density where powdery or peeling deposits began to appear. The cathodic decomposition potential for powdery or peeling deposition was more noble than for uniform bright deposition.

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