Impedance characteristics and mass transport of underfilm corrosion were studied in detail under anodic and cathodic polarization. Cathodic blisters were found to be 20 to 100 times larger than anodic blisters. Chemical analysis of the solution under the films revealed that the anodic current through the film was carried by chloride and ferrous ions, and the cathodic current was carried mainly by sodium ion in the initial stage of blistering. As a result of the charge transport, the pH of the anolyte decreased through hydrolysis of ferrous ion, while that of the catholyte increased to 12.5 or more due to the concentrated solution of sodium ion.
At the initial stage of delamination, the impedance characteristics of coated steels showed an impedance arrest in the very low frequency region. This arrest split into two-in the very low and medium frequencies-and the impedance values at both arrests decreased with time. In cathodic polarization, the impedance decreased very rapidly and the impedance spectra were extremely similar to those observed on naturally delaminated coated steels. An equivalent circuit for the degraded coated steels was derived from a physicochemical model of delamination. It was easily shown that the break point frequency which appeared in the Bode diagram as the onset frequency of the impedance arrest (phase shift =45°) was proportional to the area of delamination. Based on this, a break frequency method was proposed and examined to evaluate the degree of degradation of coated steels.

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The effects of thallium on palladium electrodeposition reactions were investigated by impedance measurements. Ethylenediamine in the electrolyte formde an adsorption layer on the electrode surface and lowered the double layer capacitance Cd. However thallium ion in the electrolyte was deposited on the electrode surface at underpotential deposited, breaking the ethylenediamine adsorption layer and increasing Cd. In addition, the addition of thallium ion to the electrolyte resulted in secondary capacitive loops and inductive loops were observed at low frequency. The secondary loops reflected the activation of a crystal growth reaction with increasing overpotential, but the inductive loops did not correspond to the growth mode of the electrodeposits. These responses suggest that the hydrogen ion adsorption reaction as the rate determining step.

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Copper test pieces were diffusion-annealed in an evacuated capsule at 1073K for 3.6ks with chips of a Cu-Zn alloy as a zinc vapor source. The test pieces were homogenizing-annealed or oxidized at 1073K for 1.8-60.3ks.
Variations in the observed surface concentration of zinc with homogenizing-annealing time differed from those calculated by the equation reported by Whittle, but coincided approximately with those caluculated using an equation taking into account the concentration-dependence of interdiffusion coefficients.
In the oxidation experiments, sudden increases in oxide layer thickness were found after a certain oxidation time. A definite difference was found between observed values for the variations in surface concentration of zinc with oxidation time and the theoretical values obtained by Whittle.

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Electrodeposition of Fe-Cr-Ni ternary alloys from mixed solutions of metal chlorides and glycine at pH 2.4 was investigated with emphasis on the state of the Cr (III) complex ions. The Cr (III) complex changed its form from a hexa-aquochromium (III) complex to an unidentified complex coordinated with glycine molecules when the solution was cathodically electrolyzed for a certain time. Electrodeposition from the solution containing the aged complex showed relatively good throwing power, and the solution was stable.

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Some factors controlling the induction period (IP) of the reaction between 1, 1, 1-trichloroethane (CCl₃CH₃) and aluminum (Al) were investigated. The results were compared with results previously reported and obtained from recent work on the reaction between carbon tetrachloride (CCl₄) and Al. It was found that: 1) A minute amount of water or oxide film on the surface of Al has the effect of extending the IP, but the effect is smaller than that obtained for the reaction between CCl₄ and Al.
Specifically, when the oxide film on the surface of Al is removed by making scratch marks, the IP is reduced to less than 5 seconds, regardless of the presence of minute amounts of water. This reaction also occurs at room temperature. 2) Unlike the cases of CCl₄, when Al purity is 93%, the IP is shorter than when pure 99% Al is used. 3) Some of the inhibitors that extend the IP on pure 99.99 and 99% Al have no effect on Al of lower purity (93%). This phenomenon does not occur when CCl₄ is employed. 4) When pure Al plate is used, the IP is 100-120 minutes in boiling CCl₄ and 4-5 minutes in boiling CCl₃CH₃, and this difference can be ascribed to the fact that minute amounts of water and components other than Al in the aluminum alloy have a minor effect on extending the IP in CCl₃CH₃.

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It was found that Zr(IV)-Cr(III) or Ti(IV)-Cr(III) composite oxide film is formed on a stainless steel by cathodic polarization in a chromate solution containing Zr(IV) or Ti(IV) ions. The method provided good oxidation resistance to SUS 430 stainless steel at elevated temperatures. In principle, it is possible to develop other composite oxides including Y(III), Ce(IV), La(III), Gd(III), and others. The present method is similar to commonly used electrolytic chromate treatment, and it has potential advantages for practical applications.

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Characteristics of silver cyanide baths for heavy electrodeposition were studied in terms of bath composition, cathodic polarization curves and the appropriate range of current densities.
It was found that cathodic overpotential increased with increases in the content of potassium carbonate, and increased remarkably with the addition of 5g/L of potassium hydroxide. The addition of more than 20g/L potassium hydroxide, however, reduced the cathodic overpotential.
When silver cyanide and potassium cyanide consentrations were both higher, there was a wide range of appropriate current densities. The addition of potassium hydroxide raised the covering power, and also increased the range of appropriate current densities. Potassium carbonate also broadened the range of appropriate current densities.
Using a bath composed of AgCN: 125g/L, KCN: 180g/L KOH: 20g/L and K₂CO₃: 20g/L and a current density of 2-3 A/dm², it was possible to obtain silver deposits of 2700μm or more.

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