The polarization characteristics of zinc and amalgamated zinc electrodes were examined by potential sweep method with various sweeping rates, KOH concentrations, and temperatures. The results obtained were summarized as follows
(1) A peak at about-1.30V (vs. HgO reference electrode) in potential sweep diagram would be due to the following reactions for both of zinc and amalgamated zinc:
Zn+2OH^-=Zn(OH)^2-_{2, ad}
Zn(OH)^2-_{2, ad}=Zn(OH)_{2, ad}+2e
The peak current was proportional to the concentration of KOH and square root of sweeping rate. The activation energy was estimated to be in the order of several Kcal/mol, which indicated that the above reactions, or the formation of Zn(OH)_{2, ad} would be controlled by the diffusion of OH^-. In addition, the reactivity between OH^- and the zinc surface would be promoted by amalgamation.
(2) One more peak was observed at about -1.15V, which was more evident for the amalgamated zinc electrode. The peak gradually turned into periodically oscillating current under the conditions of high KOH concentration and high temperature. This would probably be due to the partial dissolution of Zn(OH)_{2, ad}; in other words, both the dissolution and formation of Zn(OH)_{2, ad} occurred on the zinc surface at the same time as shown in the following equation.
Zn(OH)_{2, ad}→Zn(OH)_{2, diss}+2OH^-→Zn(OH)₄^2-
The activation energy in this association would be twice as large as that of the formation of Zn(OH)_{2, ad}.

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This paper describes the effects of addition of oxidizing agents (KMnO₄, NH₄VO₃, K₂Cr₂O₇, K₂S₂O₈, H₂O₂, and K₃Fe(CN)₆) on AC electrolysis of aluminum in alkaline solutions.
The thickest and hardest film was obtained in 0.1mol NaOH solution containing 0.05mol of KMnO₄.
A bright black film was obtained in the alkaline solution of 0.225mol NaOH containing K₃Fe(CN)₆ and K₂Cr₂O₇.
The optimum conditions were as follows.
pH: 11-12
Current density: 0.8-1amp./dm²
Electrolysis time: 0.5hrs.
Corrosion resistance of the black film was higher than that of anodized film (alumite) in H₂SO₄. Fe, Cr, and Al were found in the film by qualitative analysis.

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EDTA was added to an electroless copper plating bath as a complexing agent for the copper ion. The absorbance of the alkaline solution of EDTA-copper complex was investigated by spectrophotometric determination to estimate the copper ion in the solution.
The wave-length at the maximum absorption of the solution was approximately 740mμ. The absorbance at 740mμ was greatly affected by pH of above 10.5, but little affected by buffer solutions and co-existing substances such as excess of EDTA, HCHO, HCO₂^-, CH₃OH, and SO₄^2-. Accordingly, it was known that copper ion concentration in the solution can be estimated by spectrophotometry by adjusting pH of the solution.
In addition, the depedence of absorbance on pH was varied according to the sort of buffer solutions added to the solution. The absorbance was decreased with the increase of pH above 10.5 by the addition of Kolthoff or Universal buffer solution. While, the absorbance was decreased with the increase of pH above 8.0 or 7.5 by the addition of Sorensen or Michaelis buffer solution, respectively.
The difference of the dependence of absorbance on pH between these buffer solutions was supposed to be due to the change in the structure of complex salt affected by ammonia or glycine in the latter buffers.

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The tin-nickel deposit is composed of about 65% of tin and 35% of nickel. It has high resistance to corrosion and tarnish, but is considerably brittle and easily cracked on bending. Such an imperfection of the tin-nickel alloy was not improved by the amendment of the composition of the plating bath.
Then, the tin-cobalt alloy deposit was pursued, instead of the tin-nickel alloy. A deposited layer composed of 75-80% of tin and 25-20% of cobalt was steadily obtained from the bath containing 50g/l of stannous fluoride, 20g/l of sodium bifluoride, and 500g/l of cobalt chloride.
The plating conditions were as follows.
Temperature of bath: 65-80°C Current density: 0.5-4amp./dm² pH: 2.0
The effects of operating conditions and the bath composition on the deposit composition and cathodic current efficiency were investigated. For example, the current efficiency was above 90% for pH=2.0 at 70°C and under the current density of 2.0amp./dm². On addition of a brightner, the thickness of the deposit allowable was 100μ at maximum, and the electrolyte was stable for prolonged use. The deposit was similar to chrome plating in appearance. Moreover, it had high resistance to corrosion and tarnish, and was not so brittle as the tin-nickel alloy plating.

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The effects of bath compositions and brighteners on corrosion resistance of bright nickel plating were studied. The results obtained were as follows:
(1) The interaction between the concentrations of nickel sulfate and nickel chloride had no effects on corrosion resistance.
(2) The interaction between the cathodic current density and the concentration of total nickel had effects on corrosion resistance. Higher corrosion resistance was obtained under the conditions of lower concentration of total nickel and lower cathodic current density, or the higher concentration of total nickel and the higher cathodic current density.
(3) Corrosion resistance was varied according to the kind and concentration of brighteners in double nickel plating.
(4) The interaction between the kind of brighteners and cathodic current density had effects on corrosion resistance.
(5) However, in CASS test of triple nickel plating, the kind of brighteners and cathodic current density had no effects on corrosion resistance.

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Electrolytic Polymerization of acrylonitrile was conducted under various conditions in the presence of a small amount of hexamethylphosphoramide (HMPA)-Lithium chloride solution, and polymer films were formed on the aluminum cathode plates. The yield of polymer was increased with the increase of the concentration of HMPA-LiCl solution and current density. However, current efficiency and film resistance were decreased with the increasing current density. It was suggested that the coloration during the electrolysis shows the formation of solvated electrons, by which the polymerization of acrylonitrile is provoked.

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