The authors found out a simple and rapid analytical method of D.D.S. (dihydroxy-diphenyl sulfone) in the acidic bath for tin electrodeposition by the process of extraction and T.L.C. (thin layer chromatohraphy). The method consisted of the following 5 stages.
1) A definite volume of solution was sampled from the acidic bath.
2) D.D.S. was completely extracted from the sampled solution with ethyl acetate, and other additives in the bath were separated from D.D.S.
3) Five μl of ethyl acetate was applied on a prepared T.L. plate for T.L.C.. The T.L. plate was developed with a mixed solvent (benzene 10ml: Acetone 30ml) by ascending method. A completely separated chromatogram was obtained. The reproducible Rf values of phenol, D.D.S., and P.S.A. were 0.8, 0.6, and 0, respectively.
4) The visualization of developed T.L. plate was induced, when it was placed in a sealed chamber previously filled with iodine vapor.
A transparent glass plate was placed upon the T.L. plate to prevent its fading, and the latter plate was immediately scanned by passing through a recording densitometer.
5) The peak height of the recorded chromatogram was measured. The amount of unknown D.D.S. was calculated from an appropriate calibration curve.

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The electrodeposition of iron-zinc alloys has been studied as an example of anomalous co-deposition. The relation between composition of deposits and variables in plating was reported in the previous paper. As the mechanism of co-deposition was not quite evident in the previous paper, cathodic polarization was measured under various conditions in the present study. After the composition of the alloy deposits was determined, the polarization was expressed by the curves, consisting of three regions with respect to iron, zinc, and hydrogen, respectively. Reversions of potential of iron v.s. that of zinc were sometimes observed on the polarization curves under some conditions at certain current densities.
This fact was resulted from the sudden increase in the polarization in iron deposition against the stable potential of zinc. It would also be due to the hindrance of zinc ion to the deposition of iron and the formation of hydroxides near the cathode by the increase of pH (owing to the evolution of hydrogen).
Polarization curves shifted to nobler side with the rise of temperature, the decrease of pH value, and the increase of total metal ion concentration.

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Surface treatment was conducted on aluminum alloy, ADC 12, by chemical tin plating, electroless nickel plating, electroless nickel plating (hardening), molybdenum disulfide coating on zinc phosphating, and hard anodizing; and on aluminum alloy, ADC 7, by hard anodizing. Then, the surfaces of above treated alloys were combined with steels, FC 15, S 15C, and S 15C (hardening), and subjected to wear tests to study the effects of surface treatment.
The results obtained were summarized as follows:
(1) Hard anodizing showed the most remarkable effect and electroless nickel plating (hardening) showed the second.
(2) The treatment by hard anodizing was easier to conduct on ADC 7 than on ADC 12, and the wear resistance after treatment was higher in the former than in the latter. It was found that the hardness of the surface treated by electroless nickel plating was increased by heat treatment and its wear resistance was also improved. However, little effects were shown by soft and thin films such as treated by molybdenum disulfide coating and chemical tin plating.
(3) When 3 kinds of steel materials, FC 15, S 15C, and S 15C (hardening), were combined with surface treated aluminum alloys, the tendency to toward wear resistance was nearly the same.

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The dissolved amount, I-E curve, and normal electrode potential were determined in various concentrations (1×10^-3-1M) of alkaline solutions for aluminum (99.50%) and its alloy (5052).
The dissolved amount was measured by gravimetric method and conductometric titration with carboxylic acid in dimethyl formamide.
The results obtained were as follows:
(1) The dissolved amount of Al-Mg alloy (5052) was much greater than that of pure aluminum (99.50%). It would be due to a local battery formed between aluminum and other metals.
(2) The normal electrode potential was increased in direct proportion to dipping time and finally reached a constant value.
(3) I-E curve had a distinct inflection point in 0.025-0.05 M-NaOH solution and it was considered to be the decomposition voltage of aluminum ionic species in the solution.
(4) Conductivity and electrolysis time by a.c. were inversely proportional to alkaline concentration. It was believed that the fact was due to the peeling of sodium aluminate and re-dissolution of aluminum.
The precipitate separated from sodium hydroxide solution of high concentration was estimated to be γ-Al₂O₃·3H₂O and γ-Al₂O₃·H₂O by means of X-ray analysis and thermal decomposition method. The precipitation was prevented by the addition of sodium gluconate and sorbitol.

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The effect of solvents on self-anionic telomerization of acrylonitrile on aluminum electrode surface was studied during the course of studies on metal surface treatment by means of electrolytic polymerization processes. The results showed that the number of chain transfers was larger in the solvent of higher dielectric constant and the number was smaller with the stronger intensity of electric field.
On the assumption that the chain transfer reaction is due to the hydride ion shift, it is shown that the solvent of high dielectric constant weakens the interaction between hydride ions and also the interaction between hydride ion and cathode; therefore, such a solvent can stabilize hydride ions.

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