In electrolytic polishing, it is very difficult to observe the behavior of anode, as higher current density and bath voltage than other electrolysis, such as electro-plating or electrolytic refining, are required for electropolishing, moreover the electrolyte has higher concentration and viscosity. In investigating conditions for electropolishing, therefore, the current-anode potential currve is not used, but is used in general the current-bath voltage curve.
Using the latter curve, the investigation to find out the optimum condition of electropolishing of various metals and alloys was carried out. The appearance of anode surface differs considerably depending on bath voltage.
In this paper the result of microscopic examination and roughness of quenched high carbon steel electropolished at various bath voltage in phosphoric acid-chromic acid bath and of macrographic analysis of electropolishing mechanisum is reported as follows:
1) Polishing is not effective at 1 volt of bath voltage, and the roughness is the same before and after treatment.
2) At 2 volts, anode surface is covered with dark gray film of insoluble phosphate, and comparatively smooth that means thick film.
3) At 3 volts, the surface is aventurine with small, deep pits, which may be attributed to oxygen bubbles evolved on the anode surface, and sticking to it.
4) Current increases proportionally to voltage from 3 to 5 volts and large but shallow pits appear on the surface that means polishing becomes effective.
5) Between 5 and 6 volts, current does not increase with an increase of voltage, and to the smooth and glossy surface thus obtained, copper deposits little even in cupric sulfate solution which may be attributed to the fact that anode is covered uniformly with oxide film.
6) Over 6 volts, streaks appear on the anode surface.

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For the purpose of studying the electrochemical properties of sprayed Al coating on steel, the influences of surface exposure prior to immersion, solute concentration, surface grinding and stirring solution upon separate Al electrode (purity 99.85% sheet) and Fe electrode (0.05C mild steel sheet) in aerated 3.3N KCl solution using a vacuum tube voltmeter and a 3.3N KCl calomell cell, were first examined.
It was found that the behavior in the stagnant solution each of Al electrodes exposed for some time at a temperature of 25°C to 300°C after polishing with emery-paper No. 0/4 exhibited the similar one to that obtained in the case of the bare (as polished) Al electrode in the stirring solution, and the electrode potential value was-0.83 volt (3.3N KCl cal. scale) in a steady state almost immediatery after immersion. This value corresponds closely to the first stage steady state potential of the bare Al electrode for 30 minutes' immersion in the stagnant solution.
The electrode potential behavior of Al-Fe couples in the stagnant aerated solution was investigated by placing together a sheet of Fe as polished and a sheet of Al as polished back to back to ensure metallic contact and then this couple electrode with vinyl tape. which was demonstrated to be the most suitable by a series of investigation upon sealing effect of materials such as paraffin, cellophane, etc.,
The ratio Al area/Fe area was changed by covering the exposed metallic surface with sealing vinyl tape, and electrode potential-time curves were plotted for each ratio of 1-3×10^-4/1.
It was found that in all cases the electrode potential reached steady -0.83V almost immediately after immersion, and that when anodic area forms 0.03 per cent of the total electrode area, almost all self-polarization is cathodic and the electrode potential is anodically controlled.

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It was proved by many researchers that both alkaline and acid electro polishing of aluminum are possible. But the acid polishing method, or acid bath system, has been mostly popular, for the effect of the alkaline bath has been limited to a highly pure aluminum, the throwing power is low and the bathing control is difficult. However, if the electro polishing in alkaline bath is not the final process, satisfactory results can be expected. For example, if buffing and soak cleaning (or an electrolytic cleaning) are adoped instead of alkaline electro polishing, the process becomes simple. Especially, in the case of small or complex articles, the alkaline electro polishing method mentioned above can be adopted as pre-treatment of phosphoric acid type electro polishing or anodizing, leaving the articles on the rack as they are.
Bath composition suitable for electro polishing as pre-treatment was investigated and an electro polishing bath outstanding both in speed and effect was developed, with caustic soda as principal ing-redient, and sodium-phosphate, sodium-carbonate, glauber's salt and other weak acid alkaline salt as inhibitor.

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This study was made concerning effects of the electrodepositing conditions such as current density, bath temperature, cathodrotation, seperating films, etc. upon the internal stress of nickel electrodeposited in nickel chrolide bath.
As a result the mechanism of the internal stress was clarified.

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Relative durability of decorative copper-nickel-chromium versus nickel-chromium coatings was investigated by means of accelerated corrosion tests.
In this series of experiments bright plating baths, widely used in the present Japan, were adopted to prepare corrosion test panels.
5% neutral salt spray test and acetic acid salt spray test were used to determine the relative durability of coatings of different thickness and composition, from the standpoint of both pinhole-rusting and pitting corrosion.
As a result, it is concluded that the copper-nickel-chromium is more corrosion resistant than the nickel-chromium of the same total thickness.
Other details of discussion will follow in this paper.

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