A study was made on a method of preparing a printed Wiring board clad with metal core oxidation. Mechanisms of rectification and breakdown were investigated for preventing rectification, lowering of electrical resistivity, and breakdown of anodic oxide film under high humidity. The sealing with boiling water or high pressure steam and anodic re-oxidation in 3wt% ammonium borate bath were conducted in order to improve the electric properties of anodic oxide film formed in 10wt% H₂SO₄ bath.
The results obtained were as follows.
(1) It was considered that the rectification, the lowering of electrical resistivity, and the breakdown of the film under high humidity were due to the interactions between adsorbed water and impurities contained in its micro-porous structure.
(2) The rectification of film decreased by sealing with boiling water, and its breakdown voltage increased to 500V or higher by sealing with high pressure steam of 3 or 6kg/cm².
(3) The electrical resistivity was improved up to 5×10¹² Ω cm by anodic re-oxidation in 3wt% ammonium borate and sealing with high pressure steam.
(4) Insulation and wiring were successful by using selective anodic oxidation method.

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Zinc-oxygen secondary battery has been noticed as an automobile storage battery. An uniform and smooth deposit of zinc must be obtained from the alkaline electrolyte containing zincate ion during charging process for the purpose of better charging characteristic and longer life of the battery.
When an electrode, which had been anodically polarized to the passive state, was used, the polarization was less than that on the bare surface and did not bring about reproducible data. It was due to the evolution of hydorogen during the deposition and local deposition of zinc on the oxide surface. In alkaline zincate solution, the deposition of dendritic zinc during charging was the most serious problem.
However, an uniform and smooth deposit was obtained during charging by addition of piperonal to the electrolyte. Piperonal was decomposed in the electrolyte during the use for a long time, but it was improved by coaddition of hydrogen peroxide. Moreover, the charge-dischage cycle was much lengthened by addition of trietlylenetetramine. In such a case, a smooth deposit was also obtained after 5 cycles, though high polarization was produced in charging.

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It has been empirically known that corrosion resistance, formability, and other properties of the spangles of galvanized iron sheet greatly depend upon the variation of structural formation (general pattern) of the spangles. However, the reason of the fact has not been clarified yet.
The present study of the authors is an attempt to establish relations ammong external appearance, crystal orientation, and corrosion resistance of the spangles.
The results of the study revealed that with respect to external appearance, spangles would be divided into the following three types:
Type A (representative dendritic spangles): The spangle develops from one nucleus, and the main axes of growth linearly and radially extend with smaller branches growing out.
Type (B): The spangle grows from a nucleus in a straight line, and the axis of growth sharply divides the area into two parts: shiny area on one side and frosty one on the other.
Type (C): In this pattern, the axes of growth are generally curved and blurred, and more or less frosty areas are exhibited over the whole surface.
The results of the determination of crystal orientation of each spangle were as follows:
Type A: The crystal orientation on the plane parallel to the sheet surface was close to the basal plane of hexagonal crystals at an angle of not more than 8° to C-axis.
Type B: The crystal orientation on the plane parallel to the sheet surface was at an angle of 9-30° to C-axis. The shiny areas consisted of single crystals and the frosty ones exhibited progressive change of orientation with growth of the spangle.
Type C: The crystal orientation on the plane parallel to the sheet surface was at an angle of not less than 57° to C-axis. It was close to the hexagonal prism and consisted of polycrstals exhibiting preferred orientation.
As for corrosion resistanse, the spangles of Type A were superior to others. The corrosion resistance of the spangles was higher when the crystal orientation was closer to the basal plane of hexagonal crystals.

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The oxidation of 18Cr/10 Ni/Ti stainless steel diffusion-coated with chromium was studied regarding the change of chromium concentration with oxidation time in the region near the surface of metal. Samples prepared for the oxidation tests were diffusion-coated at 950 and 1, 050°C for 1, 3 and 5hrs.
The oxidation was made in the still atmosphere at temperatures of 950-1, 050°C, and the results were discussed by measurement of weight increase, electron probe microanalysis, X-ray diffraction analysis, and scanning electron microscopy.
Breakthrough occurred in a stainless steel as received by oxidation at 1, 050°C in 10-20hrs.; whereas, no breakthrough was observed in any sort of diffusion-coated stainless steels in less than about 130hrs. The thicker diffusion-coated layer could make the time to breakthrough longer. However, any stainless steel as received before breakthrough showed less weight increase than the diffusion-coated one at any temperature of oxidation.
It was considered that the breakthrough of the material occured when the chromium concentration on the metal surface dropped to about 10%, which led to the formation of FeCr₂O₄ by the exposure of metal surface to the air owing to cracking or peeling of oxide scale.

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Studies were made of the effects of application of three kinds of direct currents (single phase full-wave, three phase half-wave, and six phase half-wave) and other five kinds of currents (interrupted, pulse, PR, periodic alternate [DC or AC], and superimposed [DC and AC] currents) on hard anodic oxidation coatings of aluminum. Specimens were anodized at 0°C for 45min, in 100g/l of H₂SO₄ containing 15g/l of C₂H₂O₄.
The results of the experiments were as follows:
(1) The color of coating anodized by applying a direct current was dark, but it became light when a negative current was applied.
(2) The adhesion of coating was extremely poor when PR current or periodic alternate (DC or AC) current was applied.
(3) The bath voltage was higher than those by other currents when single phase full-wave or three phase half-wave direct current was applied, and the cell size of these coatings was larger. Except for superimposed (DC and AC) current, it was observed by scanning electron microscopy that the cell size became somewhat larger when a current including AC was applied.
(4) The thickness of coating was larger and its hardness was higher than those by other currents when a direct current was applied.
(5) The coating ratio was high when a direct current was applied, but it became lower when a negative current was applied.
(6) The coating ratio was higher when the density was higher; in other words, the density of each coating indicated almost the same tendency as the value of coating ratio.
(7) The results of the measurement of sulfur intensity of coating by X-ray microanalyzer revealed that the quantity of sulfur contained in the coating was less than that by a direct current when superimposed (DC and AC) current was applied, although a large quantity of hydrogen sulfide gas was evolved near the specimens.

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Electrodeposition of metals on the anodized alumina film being completely free from the substrate metal, was studied with respect to the systems of CuSO₄/oxalic acid and other solutions.
Evolution of hydrogen at the Al anode was explained in terms of the mechanism of electrostenolysis.
Al foil (20μ in thickness) was anodized in 3% oxalic acid, by which the substrate metal was completely converted into alumina foil.
The results obtained were as follows:
(1) The electrostenolysis of metals occurred on the porous part of oxide films.
(2) The electrostenolysis did not occur when the ionic mobility of alumina film was large; whereas, when the ionic current reached a limiting value, the electronic current in the oxide film became predominant so that the electrostenolysis occurred.
(3) The SO₄^2-ion was permeable to the oxide film formed in 3% oxalic acid bath; whereas, oxalate ion was not permeable to the film.
(4) The evolution of hydrogen at the anode was actually detected and the possibility of electrode-position of metals, which are nobler than H⁺ion, on the porous anodic oxide film was considered to be related with the mechanism of metal deposition in the “Anorok Verfahren (Asada's Process).”

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