The growth process and microstructure of Au films electrodeposited on pure iron from KCN bath were examined by electronmicroscopy. The nuclei formed on (001) Fe at the early stage of electrodeposition were three-dimensional plate particles. With the progress of electrodeposition, these nuclei grew up into insular form and network in morphology, and finally into a complete continuous film, which is called “Au plate crystal” by the authors. The coherencies between Au plate crystal and iron substrate were (001) Fe||(001)Au and [110]Fe||[010]Au. In the growth process, a large number of dislocations, micro-twins and stacking faults were formed in the Au films. The density of dislocations was about 3-5×10¹⁰cm^-2 and that of micro-twins was about 2×10¹⁰cm^-2. The formation mechanism of micro-twins was identical with Burbank-Heidenreich's process or Hall-Thompson's process in evaporation. The length of twins was about 400-650Å. The sub-grains of less than 0.1μ in diameter were observed in the Au films of high indices formed on the substrate plane of high indices. The rotation Moire patterns existed in the vicinity of some of the sub-grain boundaries. Quantitative electronmicroscopic analysis of the Moire patterns and diffraction patterns revealed the growth of some of the crystals having orientations rotated and tilted at certain angles to the main plate crystal during their growing process.

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Gold was electrodeposited on pure (001) Fe substrate from KCN bath, and the effects of current density and substrate temperature on nucleation and epitaxy of Au were examined by electronmicroscopy. It was attempted to apply Walton's “Statistical Theory of Nucleation” to the Au deposits. Linear relations were found between the logarithm of nucleation rate (log I) and the inverse number of substrate temperature (1/T), and between the logarithm of I (log I) and the logarithm of formation rate of adatom (log R). The Au films obtained in the present experiments made epitaxial growth on (001) Fe substrates. The epitaxy of Au films was controlled by the question whether the Au particles can easily be rearranged when they coalesce with the neighboring particles. High current densities had an effect on the improvement in the epitaxy of Au films, but the substrate temperature made a little contribution to the epitaxy.

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This paper describes the electrodeposition of nickel from Ni (CF₃COO)₂-KBr-MeOH solutions for studying the electrodeposition mechanism of nickel. Bright and smooth nickel deposits were obtained from Ni(CF₃COO)₂ 500g/l-KBr 8.0g/l-MeOH bath under current density of 2.0-14.0 Amp/dm² at 50°C. The current efficiencies in this case were about 100% for both of cathode and anode. The rate controlling step in electrodeposition of nickel from Ni(CF₃COO)₂-KBr 8.0g/l-MeOH bath under current density of 1.2-3.9Amp/dm² was a charge transfer reaction. The main values in these experiments were as follows: Apparent transfer coefficient: α_c=0.69, Apparent valence: n=1.1, Apparent exchange current density: i_oc=0.084Amp/dm², Tafel slope: b_c=-0.082V, and Apparent activation energy: E_c=5.3kcal/mol.

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Binding energies of the elements in binary aluminum alloys and their anodic oxide films formed in sulfuric acid solution under a constant current density were studied by X-Ray photoelectron spectroscopy. The results obtained were as follows. (1) The binding energies of Al_2P, Al_2S, and O_1S electrons in aluminum alloys and thier oxide films were nearly identical with those in high purity aluminum and its oxide film, respectively. (2) The binding energies of Mg_2P electrons in Al-10% Mg alloy and its oxide films were estimated to be 50.9eV, which was found to be about 1.0eV higher than the binding energy at Mg_2P electron for MgO and the oxide found in the spectrum of the Mg metal. The tendency for this energy shift was also clearly found in the spectrum of MgKL₃L₃ Auger electron. (3) The spectra of Si_2P electrons in Al-3% Si alloy and its oxide films were not clearly detected by the interferences of the spectrum of plasma loss due to the emission of Al_2P electron and by the spectrum of Al_{Kα3, 4} X-Ray lines at Al_2S electron.

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Studies were made of the effects of application of pulsating current wave form on hard anodizing of aluminum. Specimens were anodized at 0°C in 100g/l of H₂SO₄ containing 15g/l of C₂H₂O₄, at a constant electric quantity of 160A·min/dm² with changing the current density and the time of pulse current. Direct currents (single-phase full-wave, three-phase half-wave, and six-phase half-wave), interrupted current and superimposed (DC and AC) currents were applied to compare with pulse current. A thicker coating is obtained when a direct current wave form containing high ripple percent was applied. When pulsating current (high output 4A/dm² 30sec, low output 2A/dm² 7.5sec) was applied, the hardness of coating was higher than hard anodic oxidation coatings using a direct current. The hardness became higher when the ratio of the time between the high output and the low output was 4:1. It was observed by scanning electron microscopy that the cell size of the cross section of coatings was independent of the current wave formes used. There found no obvious relation between the cell size and the hardness.

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The theoretical equations of the temperature difference (Δt) in a flow of electrolytes between the electrolyte and the electrode surface were derived from the heat transfer theory and Joules heat caused by electrolytic current and overvoltage: in laminar flow Δt=K_liηl^0.5/u^0.5 and K_l=0.36 a^1/3ν^1/6/λ in turbulent flow Δt=K_tiηl^0.2/u^0.8 and K_t=6.67a^1/3ν^0.47/λ where i: current density, η: overvoltage, l: length of specimen, u: flow rate of electrolyte, a: thermal diffusivity, ν: kinematic viscosity, λ: thermal conductivity. The results of experiments in laminar flow of electrolytes were as follows: the theoretical temperature differences calculated by the above equation agreed well with the data obtained in the anodizing of aluminum where the measured overvoltages are constituted mainly by activation -and resistance-over-voltage. However, in the case of electro-plating and -dissolving, the experimental data were lower than the theoretical values owing to the IR drop and the concentration overvoltage contained in the measured overvoltage.

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