The following results were obtained from the study of anodic treatment on aluminum or aluminum alloys in the mixed solution of aliphatic acid, sulfamic acid and sulfuric acid:
1. Appropriate bath composition was of 25-30g/l of tartaric acid, 100-110g/l of sulfamic acid and 5-6g/l of sulfuric acid, with which fairly stable anodizing was possible.
2. The bath of the said composition, like that of prevailing mixtures of aromatic and sulfuric acid, produced various colors such as gold, amber, bronze, black, etc. according to the control of anodizing conditions and to the selection of aluminum or aluminum alloys, furthermore its cost was lower.
3. Dissolved aluminum amount in the bath had significant effects on the color value, and it was necessary to maintain the amount within a range of 0-1g/l.
4. Mean hardness of the cross section of the coating obtained under the condition of 2-3A/dm² of current density, 50-60V of maximum voltage and 25°C of bath temperature, was 650HmV; despite the room temperature-anodizing the hardness was thus high.
5. In general, a bath temperature of a little over 20°C was recommendable, and adjusting the composition of the mixed solution seemed to permit satisfactory work even in a higher anodizing temperature such as 30-35°C.

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The fundamental condition of electroless plating of cobalt-nickel alloy (the plating bath contained hydrazine as a reducing agent) or the relation between plating rate and the composition of deposited film was investigated.
The results obtained were summarized as follows.
(1) Caustic alkaline tartrate bath was selected as a practical plating bath having relatively high plating rate and bath stability.
(2) The optimum plating condition of the bath was determined as follows with respect to plating rate, bath stability, and appearance of plated film.
CoCl₂+NiCl₂=0.05mol/l
CoCl₂/NiCl₂=variable
N₂H₄⋅2HCl=1.0mol/l
Na-tartrate=0.4mol/l
Thiourea=3p.p.m.
pH=12.0(NaOH)
Temperature=90°C
(3) The decomposition of bath, or a drawback during such a process of plating, was much prevented by the addition of 2-3p.p.m. of thiourea without depression of plating rate.
(4) Under the above condition of bath, various alloys containing any ratio of cobalt to nickel were obtained by controlling the ratio between the both metals in the bath.

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There are only a few reports on the anode behavior in copper cyanide plating baths, since the anode behaviors seem to have no effect on the cathode deposits directly, and anode passive films to have little reproductivity.
The author determined the anode polarization in copper cyanide plating baths under various electrolytic conditions, changing bath compositions and additives.
The results obtained were summarized as follows:
1) Comparing K⁺ bath with Na⁺ bath, the anode polarization in the K⁺ bath was less than in the Na⁺ bath within lower current density range than that required to make the anode passive, which, however, was lower in the K⁺ bath than in the Na⁺ bath.
2) With low concentration of copper and free cyanide, the anode passive occurred at low current density.
3) With increasing carbonate concentration, the current density required to make the anode passive decreased and the anode polarization increased. The same phenomena were observed at very low concentration of carbonate, but this was not obvious in the Na⁺ bath.
4) The current density required to make the anode passive became high by agitating the bath, elevating the bath temperature, using PR (periodic reverse) current and the like.
5) Many additives produced little effect on the anode behavior.
6) The difference in material of the anode had little effect on the anode polarization. But the anode obtained by electroforming from the sulfate bath with thiourea, was harder to be made passive than the others.
7) The color of the anode passive film was reddish brown within low current density, it changed to blackish brown or black at the current density high enough to produce oxygen bubbles, and at higher current density, it turned bluish white. This may indicate that the films consisted of cuprous oxide at the first, cupric oxide at the second, and insoluble carbonate or cyanide at the last stage.

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The dyeing mechanism of anodic oxide coating of aluminum was studied by means ofζ-potential and surface charge density. The result was as follows:
1. The isoelectric point of coating was about 6, and the coating was positively charged in water.
2. For pH<6, the ζ-potential of coating in HCl solution was positive and it increased with the concentration of HCl. For pH>6, the ζ-potential in NaOH was negative, and it decreased with the concentration of NaOH.
3. The ζ-potential of coating in HCl of acidic dyestuff was negative. It decreased with the increase of pH.
4. For pH<6, the surface charge density calculated from ζ-potential in HCl containing NaCl, became greater than that in HCl. For pH>6, the surface charge density in NaOH containing NaCl became smaller than in NaOH.
5. For the pH varying from 4 to 10 or the low concentration of acidic dyestuff solution, the surface charge density was proportional to the amount of the adsorbed dyestuff.

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