A chromium plating bath principally composed of chromic anhydride with a large content of fluosilicate (K₂SiF₆ of 3-55g/l) was studied with respect to the current density.
The following results were obtained:
(1) The solubility of potassium fluosilicate in chromic acid solution was increased by means of preliminary electrolysis.
(2) In the electrolysis for an extremely short time, the current efficiency was always higher than that of the Sargent Bath. However, the efficiency was above 50% on the side of higher temperature and higher current density.
When the time for electrolysis was longer, it was difficult to maintain such a high current efficiency, but the efficiency was likely to be higher than that of the Sargent Bath.
(3) This plating had a wider range of brightness than the Sargent Bath. Burnt deposits were not produced in this plating even under a high current density as 200amp./dm².

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Pure aluminum (99.50%) was electrolyzed with alternating current in alkaline solutions of various concentrations containing glycolic acid, which had been prepared by the reduction of oxalic acid. After that, its surface state was observed.
Sodium hydroxide solutions (0.1-0.4% in concentrations) containing 5-14% of sodium glycolate were used as electrolytic solutions.
The following results were obtained:
(1) When a stainless steel (18-8) was used for the other electrode, a golden film was obtained by the electrolysis for 30-60min. under current density of 3-6amp./dm².
The thickest (9.5μ) and hardest (14.2 by Martens' scratch tester) film was obtained in 0.3- 0.4% solutions of sodium hydroxide containing 12% of sodium glycolate.
The maximum reflection absorbance of the colored film was found at 385mμ and the color tone was similar to that of the anodized film from oxalic acid-sulfuric acid soution.
(2) When lead was used for the other electrode, a black film was obtained under the same conditions as above (1), and the thickest and hardest film was obtained in 0.1% solution of sodium hydroxide. The degree of coloring was deeper in proportion to the electrolysis time.
The color of the film was different according to the kind of the other electrode. However, the coloration would be due to the formation of chelate compounds by theelectrolysis of glycolic acid.

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In the previous paper, the semi-conductive properties of titanium oxide coatings were explained in terms of oxygen deficiency and gradients of oxygen concentration within the coatings. In order to prove this hypothesis, the coatings were examined with X-ray diffractometer, micro-analyzer, thermal analyzer, etc.. The following conclusions were drawn from the results of these analyses.
The flame sprayed TiO₂ powder mainly comprised rutile crystals containing small amounts of anatase and brookite. The flame sprayed coatings of titanium oxide were composed of multi-components, including rutile, brookite, anatase, Ti₃O₅, Ti₂O₃, TiO, ete.. In addition to the above components, the coatings of BaTiO₃-TiO₂ system contained glassy BaTiO₃.
Heat treatment of the coatings promoted the crystallization, but lattice parameters of rutile were not varied; whereas, tetragonality of BaTiO₃ was steadily increased with the rise of treating temperature.
The dispersions of Ti and Ba were rather good, but that of oxygen was not good. The concentration of oxygen was made uniform by the heat treatment.
Direct heat treatment in the air gave steep gradients of oxygen concentration; but the concentration within the coatings was made uniform by the heat treatment of the coatings covered with carbon.
A steep gradient oxygen concentration was produced near the surface of the coatings by means of a fired-on silver electrode.
Flame sprayed TiO₂ coatings had about 1.3wt% of oxygen deficiency; while the deficiency in TiO₂-BaTiO₃ coatings was only 0.2wt%, which depended on the ratio of TiO₂ to BaTiO₃. The degree of oxygen deficiency in the coatings was decreased by heat treatment.

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The composition and temperature of electroless copper plating baths were investigated by means of design of experiment for the purpose of clarifying the effects of the above factors on the deposition rate of copper and the decomposition in the bath.
Tartrate or EDTA was used as a complexing agent. The deposition rate of copper in such a bath depended upon temperature, concentrations of copper ion and formaldehyde, and the interaction between temperature and copper ion concentration. However, the deposition of copper from EDTA bath greatly depended upon temperature and concentration of copper ion, but slightly upon other factors. Whereas, the deposition from tartrate bath fairly depended upon concentration of formaldehyde and the interaction between temperature and copper ion concentration as well as other factors.
The decomposition in EDTA bath depended upon pH as well as temperature, concentrations of copper ion and formaldehyde, the effects of the four factors were nearly in the same degree. In addition, the decomposition rate was increased with the increase of pH value.

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Investigations were made on the effects of halogen ions in nickel sulfate plating baths of various concentrations.
Experiments were conducted on natinal electrode potential of electrolytic Ni anode, anodic polarization, anode potential, anode efficiency, cathodic polarization, bath voltage, and a few properties of Ni electrodeposits.
The results obtained were as follows:
(1) It was found that Cl^-, Br^-, and I^- ions promoted anodic dissolution; whereas, F^- ion acted as an inhibiter for the anodic dissolution. They were arranged in dessending order of reactivity as follows: Cl^->Br^->I^->F^-
(2) Halogen ions had effects on hardness and stress of Ni deposits.

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Observations and discussions were made for the mechanisms of electrodepositions of copper from sulfate and cyanide baths and of nickel from sulfamate and sulfate baths.
The behavior of initial crystal nucleation and crystal growth was observed under an electron microscope.
Main considerations obtained were as follows:
(1) The electrodeposits of Cu and Ni were nearly identical in crystal forms, because the both metal had the same crystal lattices (face centered cubic lattices).
(2) Different types of electrodeposited crystals were observed between simple salt and complex salt baths.
(3) Initial crystal nuclei had semi-spherical form with diameter of less than 3000Å. The machanism of nucleation was supposed to consist of the followig three stages; that is, the presence of a huge ionic mass in the electrolytic bath, its continuons discharge, and instantaneous deposition of the corresponding metal.
(4) The nucleation seemed to be concentrated around the scratches on the substrate caused by grinding and in the neighborhood of grain boundaries of crystals.

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