Electrodeposition of water soluble alkyd paints was studied mainly on aluminum alloys and the following results were obtained.
(1) A chemical condenser was formed on the aluminum alloys as the result of the anodic oxidation, and the oxidized film increased the electric resistance of the circuit and inhibited electrodeposition.
(2) However, the tendency of forming the condenser depended on the kinds of paints. When the above tendency was slight, the amount of deposit on aluminum alloys was sometimes larger than that on steels.
(3) In general, the anode metal showed weight loss by being dissolved during electrodeposition. Regardless of the resistance of oxidized film, the metal showing larger weight loss or anodic dissolubility tended to result in a smaller amount of deposit.
(4) The wave form of the current also gave remarkable effects on the electrodeposition of paints on aluminum alloys. The full-wave rectification of single phase gave a larger amount of deposit as compared with the constant direct current with the same average value.

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The determination of a trace amount of tungsten alloys in the initial stage of electrodeposition was studied by using radioisotope ¹⁸⁵W as tracer.
The counting of ¹⁸⁵W was observed at the cathode potential 20-40mV earlier than the first apparent deposition.
When the electrolyte was composed of tungsten salt only, lower tungsten oxide was reduced at the cathode and the reduction was promoted by the addition of hydrazine sulfate.
However, the reduction was decreased by the addition of supporting electrolytes such as tartrate and citrate. Accordingly, the supporting electrolytes had no direct effects on the reduction of tungsten ion, but they formed effective complex salts with Fe, Co, Ni, etc.

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Effects of fundamental plating conditions on copper deposition rate were investigated by means of gravimetric method and the results were discussed by the total current-potential curves determined under various conditions.
E-I curves were determined by potentio-kinetic method with scanning rate of 10mV·s^-1.
pH of the solution had the greatest effects on the deposition rate, and the effects of the concentration of copper salt or formaldehyde was less than the former.
In general, the behavior of total current-potential curve was fairly agreed with the expected fundamental behaviors of local anode and cathode reactions reported previously. Some disagreement was fond in the behavior of cathode reaction, which was considered to be due to the interaction between copper complex ion and formaldehyde to the solution.
It was made clear that agitation of the solution, in the state of free from soluble oxygen, increased deposition rate.
On the other hand, agitation of the solution in the air-saturated state, made the deposition rate somewhat less, which was considered to be caused by the increase of diffusion current of soluble oxygen resulting in the decrease of the efficiency of cathode reaction.
The effects of stability of the solution by agitating in the air-saturated state may be explained as follows: the increase of diffusion rate of soluble oxygen inhibits Cu₂O (formed by homogeneous reaction) from reduction to active Cu nucleus which accelerates decomposition reaction.

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Effects of addition agents in chemical copper plating solution were mainly investigated by total current-potential curves.
Decrease of deposition rate resulted from the addition of a small amount of thiourea was proved to be caused by its poisoning action on anodic reaction of formaldehyde. At the same time, remarkable improvement was observed in the stability of the solution.
It was found that inhibiting action of hexamine was due to the suppression of cathode reaction, in contrast with the addition of thiourea.
EDTA promoted the plating reaction, and it was considered to be due to the excitation of local reaction caused by the co-existence of formaldehyde and copper-EDTA complex ion.
In conclusion, a chemical copper plating bath is recommended for practical use, having the following composition and operating conditions.
Copper sulfate 0.04M
Rochelle salt 0.1M
Caustic soda to pH 12.5
Pam-formaldehyde 0.3-0.5M
Thiourea 0.05-0.2mg/l
Temperature 20-25°C
Agitation Agitation in the air-saturated state

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The ζ potentials of paint particles and the electrode potentials in the process of electrophoretic coating were determined and the mechanism of electrodeposition was elucidated by examining the relations between the both potentials. The ζ potentials were obtained from the electrophoretic velocity of the particles in a constant electric field, assuming that Helmholtz-Smoluchowski's equation would be applicable to spherical particles. While, the electrode potentials were measured on Pt, Ni, and Fe anodes, each having the area of 7.85×10^-3cm², under the conditions of being anodically polarized and painted with constant current. Furthermore, the curves representing the relations of potential-time and potential-current were discussed and the effects concentration of the paint solution on the latter curve was examined.
As the results, it was suggested that the electrophoretic deposition of the paint particles would be accelerated by the diffusion layer formed by anodic reaction on the electrode. The diffusion layer would probably consist of oxide of anode metal and or hydrogen ion adsorbed. Although electrophoretic coating is usually applied to primary coating, the deposited paint film on the electrode does not always serve as an insulator. However, it would be probable to apply the electrophoretic coating to finishing in thick layer. However, there may be some disadvantage in the above application for practical use due to the properties of paint itself, with which this study is not concerned.

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