Gas boronizing of iron with the mixture of diborane and either hydrogen or argon was carried out by using electric resistance and high frequency induction furnaces. Needle shape boride layers were obtained when specimens were treated with the mixture of diborane and hydrogen in the high frequency induction furnace. Microscopic examination of the microsections taken from the cross sections of the specimens and the results of X-ray diffraction showed that the boride layers consisted mostly of a single boride of Fe₂B, and partially of two borides of FeB and Fe₂B. Boronizing reaction of iron with diborane was supposed to be brought about under the conditions that the decomposition of diborane was reduced by the excess of hydrogen or produced only near the surface of the specimen. The rate of boride layer formation was not in accordance with the parabolic law of diffusion.

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Morphology of zinc electrodeposits was studied, and microscopic observation of the deposits was conducted. Smooth zinc deposits were obtained in a limited concentration range of about 8mol/l KOH+0.65mol/lZnO, and dendritic crystallization was observed at low zincate ion concentrations. The dendrites were fern-like, and one-two-or three-dimensional, and their crystal size increased with a decrease in the zincate ion concentration of the bath. The growth of the dendritic zinc crystal was inhibited by the presence of small amounts of tellurium and lead ions in the bath, and thus the morphology of the zinc deposit changed from dendritic to laminar and to granular structures by these ions.

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Pure aluminum (A 1100) and AI-Mg-Si alloy (A 6063) sheets anodized at 15V in 10V% H₂SO₄ solution were reanodized at different voltages (3, 5, 7, and 9V) in the same solution. Alternatively they were anodized in 10V% H₂SO₄ solution by applying current of periodically reversed polarity at various current densities. These anodized sheets were electrolyzed in a solution of H₂SO₄:50g/l, SnSO₄: 20g/l by applying alternating current (50Hz, 10V) and thus colored films of purple, blue, green, gray, pink, etc. were obtained. It was found that these various colors are due to the deposition Sn by the AC electrolysis at the metal-oxide interfaces roughened to different extent by the different primary anodizing processes.

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The electrolytic oxidation of chromium (III) has been studied in a cell without diaphragm. Oxidation rate of chromium (III) into chromium (VI) increased with increases in pH, concentration and cathodic current density. PbO₂ was found to be most preferable for the anode material due to the catalytic action of PbO₂ for chromium. By increasing the cathodic current density or by using cathode materials of low hydrogen overvoltage, reduction of chromium (IV) at the cathode could be reduced. (NH₄)₆Mo₇O₂₄ which was used as additive, increased the anodic current efficiency by about 10%-15%. Since pH could be maintained at a value from 1.8 to 2.5 by constantly adding chromium hydroxide, chromium (VI) is recovered with good efficiency.

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