Tungsten-iron alloys were deposited from ammoniacal alkaline tartrate electrolytes in a wide range of metal composition. The iduced codposition was studied by steady-state and galvanostatic pulsed d.c. electrolysis, X-ray diffraction of electrodeposits, and direct chemical analysis of the metal composition of the solution sorbed on the electrode surface. Comparison of alloy composition was made between the alloy obtained by steady-state d.c. electrolysis and the alloys obtained by interrupted galvanostatic pulsed d.c. electrolysis. The result showed that, in the steady state of electrolysis, the tungsten percentage of the metal contained in the solution adjacent to the cathode surface was extremely higher than that in the bulk of the electrolytes having different metal compositions. The result of direct chemical analysis of the solution near the cathode surface showed that the preferential deposition of tungsten was not an anomalous phenomenon. It was found that the preferential deposition of tungsten occurred by the following interaction between electrolytes and cathode materials. (a) There was a preferential adsorption of tungsten in some ionic state, and (b) The tungsten percentage of the metal contained in the adsorbed layer, covering both of non-polarized and polarized electrodes, was higher than that in the electrodeposits.

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Galvanic corrosion between titanium and a titanium-palldium alloy was studied by measuring the polarization characteristics and the weight loss by dipping in 0.5-1.0N HCl at 90°C. The following results were obtained: (1) When titanium was contacted with a titanium-palladium alloy, the corrosion rates of the both metals were almost the same at any concentration of HCl. When the concentration was 7N or higher, their corrosion rates were higher than that of titanium alone in HCl. (2) An active behavior was observed in the anodic polarization curve of titanium when the concentration of HCl was not lower than 1N, but the behavior was not observed in the alloy when the concentration was up to 8N. The coupled potential of titanium and the alloy was at a potential nobler than the critical potential for passivation of titanium in a dilute HCl up to about 3N. When the concentration was increased to 6-7N, the coupled potential was in the incomplete passivation region. When the concentration was 7N or higher, the coupled potential was at the peak current of passivation.

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The surface film, produced by cathodic treatment of steel sheets in a dilute chromic acid solution containing small amounts of sulfuric acid and a fluoride, consisted of an upper layer of hydrated chromium oxide and a lower layer of metallic chromium. Low carbon steel sheets of various surface states specially prepared were subjected to cathodic treatment in the dilute chromic acid solution, and then, coated with clear epoxy-phenolic lacquer. The examinations of surface roughness, reflectivity, and lightness were made on the steel substrates, cathodic-treated sheets, and lacquered sheets. The results of examinations were as follows. The surface roughness of cathodic-treated sheets was almost the same as that of original steel substrates. The reflectivity of cathodic-treated sheets largely depended upon that of original steel substrates and the former value was lower than the latter value. The reflectivity of the lacquered steels merely depended upon that of original sheet substrates. The lightness of the cathodic-treated sheets depended upon that of original steel substrates; that is, the former linearly increased with the increase of the latter. The lightness of the lacquered sheets also depended upon that of original steel substrates, and the relation between the both was expressed by a linear function.

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Samples of low carbon steel sheets containing various amounts of metallic chromium and hydrated chromium oxide were prepared by cathodic treatment in a dilute chromic acid solution. The samples obtained were then baked and coated with a clear lacquer. The examinations were made for the effects of amounts of metallic chromium and chromium oxide on reflectivity, lightness, and chromaticity of the cathodic-treated sheets, baked sheets, and lacquered sheets. The results were summarizedas follows: The metallic chromium had no effects on the reflectivity of cathodic-treated sheets. However, it had effects on the lightness of cathodic-treated sheets in the range of not higer than 0.3-0.4mg/dm² of chromium oxide. The reflectivity of cathodic-treated sheets decreased with the increase of chromium oxide in the cathodic film; however, it remained unchanged when the amount increased to 0.5mg/dm² or higher. The lacquered sheets showed a constant value of reflectivity regardless of the amount of chromium oxide. The lightness of cathodic-treated sheets decreased with the increase of chromium oxide however, it remained unchanged when the amount increased to 0.4-0.5mg/dm² or higher. The lacquered sheets showed a constant value of lightness regardless of the amount of chromium oxide; however, in the lacquered sheets of high lightness, their values of lightness depended on the amount of chromium oxide. The surface chromaticity of cathodic-treated sheets showed “a” values of -0.6-+0.7 and “b” values of -0.5- -0.6, which indicated that the hue was pale blue with low saturation. The above values of “a” and “b” were obtained at the chromium oxide amounts of not higher than 0.2-0.25mg/dm² showing bluish luster undiscernible with naked eyes. The hue of lacquered sheets slightly shifted to the yellow-green zone and remained constant regardless of the amount of chromium oxide. After the cathodic-treated sheets were baked at 210°C for 20min., their bluish hue slightly faded.

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The self-regulation of sulfate concentration by the addition of Sr²⁺ to a chromium plating bath saturated with SrSO₄ was studied. The following results were obtained: (1) Since SrSO₄ is a strong acid salt, the solubility of SrSO₄ in low pH solution such as a chromium plating bath was not much higher than that in its aqueous solution. (2) The SO₄ concentration could freely be regulated by the addition of SrCO₃ to the chromium plating bath. (3) The decrease in the solubility of SrCO₃ conformed to “common-ion effect” in the chromium plating bath, but not in the aqueous solution. It would be more clear by assuming activity instead of concentration. Namely, the ionic strength was higher and steady in the chromium plating bath and was supposed to be proportional to CrO₃ concentration; but it was changeable in the aqueous solution. (4) For example, the solubility of SrSO₄ (as SO₄) was 1.4g/l in chromium plating bath containing 50g/l of CrO₃ at 55°C. When SrCO₃ of 6.0g/l was added to the bath, the SO₄ concentration became 0.5g/l, by which the plating bath for self-regulating SO₄ was prepared.

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The self-regulation of fluorosilicate concentration by the addition of K⁺ to a chromium plating bath saturated with K₂SiF₆ was studied. The following results were obtained: (1) Since K₂SiF₆ is a strong acid salt, the solubility of K₂SiF₆ in low pH solution such as a chromium plating bath was not much higher than that in its aqueous solution. (2) The decrease in the solubility of K₂SiF₆ conforming to “common-ion effect” did not agree to the following dissociation. K₂-SiF₆→2K⁺+SiF₆^2-. (3) The reason was explained by the following hydrolysis of K₂SiF₆: K₂SiF₆+H₂O→2K⁺+SiF₅(OH)^2-+HF. The dissociation of a fluorosilicate having higher solubility such as Na₂Si F₆ was as follows: Na₂SiF₆→2Na⁺+SiF₆^2-. Whereas, the dissociation of a fluorosilicate having lower solubility such as BaSiF₆ was as follows: BaSiF₆+2H₂O→Ba²⁺+SiF₄(OH)₂^2-+2HF. The results of experiments well agreed with the basis of these dissociations. (4) For example, the solubility of K₂SiF₆ was 10g/l in chromium plating bath containing 250g/l of CrO₃ at 55°C. Therefore, the plating bath for selfregulating SiF₆ was prepared by the addition of a small amount of K₂CO₃ to the bath. The solubility of K₂SiF₆ was 7g/l in low concentration chromium plating bath containing 50g/l of CrO₃ at 55°C. Since the optimum concentration of K₂SiF₆ in this bath is 0.6g/l, 27.5g/l of K₂CO₃ shall be added to get the self-regulating bath. However, this composition was not adequate for the chromium plating bath owing to the increase of pH value.

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Various pretreatments of copper and copper alloys (beryllium copper and phosphor bronze) were examined for electroplating of thin permalloy film. Attention was paid to internal stress relieving, surface leveling and adhesion of permalloy film. Heat treatment of the substrate was effective for homogenizing and adhesion of electrodeposited film. The higher temperature for treatment was required for the beryllium copper alloy than for copper or phosphor bronze. Electropolishing was the best method for surface leveling of the substrate. However, the surface of copper alloys was supposed to be covered with an oxide film after the electropolishing from the fact that it took a long time to reach a stable immersion potential. Therefore, the cyanide bath of high pH had to be used for the flush copper plating after the electropolishing. It was found that copper alloys can be used for the substrate of magnetic wires by the application of copper flush plating. The copper flush plating was also very effective for homogenizing of the permalloy film.

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The tests of galvanic anodes for cathodic protection were conducted on materials of Al-Zn, Al-Sn, Al-Cd, and Al-Zn-Sn alloys in an artificial seawater by using an apparatus for galvanostatic electrolysis. Corrosion aspects of the test pieces after 10-day immersion were analyzed by X-ray diffraction patterns and discussed by Hansen's Constitutional Diagram of Binary Alloys. The following conclusions were deduced from the change in anodic potential of aluminum alloys during 10 days and the current efficiency after that period: (1) Among Al-Zn alloys, Al-Zn (5.0-10.0) alloys showed good results. (2) None of Al-Sn and Al-Cd alloys were promising. (3) Among Al-Zn-Sn alloys, Al-Zn(3.0)-Sn (0.5) alloy and Al-Zn(3.0)-Sn (1.0) alloy had the best results.

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