The characteristics and the plating conditions of Zn-monoethanolamine bath and of Cd-triethanolamine bath were investigated.
The results obtained were as follows:
1) The electrolytes of both baths was not poisonous, bat somewhat unstable forming easily precipitate of metal hydrides.
2) When more mono- or triethanolamine was added to the bath, the electrolytes became more stable, but the cathode polarization potentials were lowered markedly.
3) The current efficiencies of the electrodes were nearly 100%, and the optimum cathode current density for good deposit was less than 0.4A/dm².

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Buffing ability and degreasability from the polished surfaces were studied with buff compositions prepared from various fats and oils. As a result, degreasability seemed to be depending on the thickness of the film of fats and oils spreaded over the polished surfaces.

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Cathode potentials of copper during the electrolysis of cyanide copper solutions were measured under the unstirred conditions. Concentrations of the solutions of pH 10 and temperature 30°C, were from 3 to 80g/l CuCN.
The factors affecting cathodic polarization have been discussed. Static potentials of copper were almost constant in a wide range of concentrations of the solution, provided the mole ratio, [CN]/[Cu], of the constituents was kept unchanged. However, the increase in the mole ratio, [CN]/[Cu], in the solution gave rise to the gradual increase of negative potential. When the concentration of copper cyanide in the solution is kept relatively small, polarization increases as the mole ratio, [CN]/[Cu], is decreased. On the other hand, polarization decreases as the mole ratio, [CN]/[Cu], is decreased when the concentration of the solution becomes large. These facts can be explained from the relation between the limit current density of the copper deposition and the concentration of the solution, and from the change of [CN]/[Cu] in the solution adjacent to the cathode due to the liberation of CN^- ions during electrolysis.

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The spalling phenomenon of the outer aluminum layer of aluminized steel heated at temperatures between 500 and 600°C for a long time and the process of void formation in the iron-aluminum diffused layer of the aluminized steel heated at higher temperature were investigated.
When the aluminized steel is heated in the range from 525°C for 2 hours to 650°C for 10 minutes, the outer aluminum layer of the steel becomes to spall easily. This spalling phenomenon is generally considered to be due to the difference of expansion coefficients between the aluminum and alloy layers. In addition to this, it is considered that the vacancies are produced in aluminum adjacent to the boundary between the aluminum and alloy layers by diffusion of aluminum into the steel, and this vacancy formation contributes to the spalling phenomenon under the shearing stress near the boundary layer induced by the difference in the thermal expansion coefficients described above.
The void in the alloy layer of the aluminized steel was not formed yet by heating at 750°C for 5 hours, but the void formation grew remarkable with further heating of higher temperature. The activation energy of the void formation is nearly equal to that of diffusion of aluminum into steel. Accordingly, it is confirmed that the void formation is due to the diffusion of aluminum into iron.

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