This paper describes a new process to obtain a coating having very high titanium content and high corrosion resistance on iron substrate.
The process was to conduct electroplating of nickel or copper on the iron substrate previous to the titanium vapor-plating. The intermediate layer acted as a barrier to prevent iron from diffusing into the titanium layer so that the purity of titanium in the surface layer was kept at a very high level.
The concentration of titanium in the vapor-plated layer was confirmed to be above 95% by measurement with an X-ray microanalyzer. Whereas, the concentration in the conventional vaporplatings with no intermediate layer was 30-70%.
Corrosion resistance of the specimens treated by this process showed excellent results by testing in various corrosive solutions.

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Microscopic observation, measurement of hardness, CASS and EC tests, and measurement of corrosion potential were conducted to examine the effects of polishing, tension, bending, and welding of substrates for the specimens plated with bright nickel deposit.
The results obtained were as follows:
1) Corrosion resistance was lower with the increase in surface roughness of the substrate and the effect was greater with the decrease in thickness of plated layer.
2) The electrodeposited surface was rougher in the initial stage of deposition when the original substrate surface was rougher and the effect was greater with the increase in current density.
3) The tension of the substrate had little effects on electrodeposited layer and corrosion resistance.
4) On bending of the substrate, a few rough points were observed in the initial stage of deposition. Non-uniform distribution of hardness was revealed on account of the bending deformation in parts, by which corrosion resistance was lowered.
5) The defects in welding of the substrates had effects on corrosion pattern.
As mentioned above, the treatments of substrate in plating works had little effects on corrosion resistance. Whereas, combination of unsatisfactorily controlled factors such as defects in current density, purity of solution, and brighteners seemed to have greater effects on corrosion resistance.

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Steel, which has been treated by zinc-cyanide plating, is susceptible to hydrogen-embrittlement, though it is very powerful in rust prevention and throwing power or economically profitable. For this reason, it is difficult to be applied to thin spring material in practice.
In order to solve the problem, eight kinds of baths, containing Zn(CN)₂58.7g/l, NaCN 24.5-100g/l, and NaOH 35.0-160g/l were selected to measure their hydrogen-embrittlement, throwing power, and current efficiency. Then, the effects of concentration of NaCN or NaOH and electrolytic conditions on the above three factors in plating of high tension steels such as SK-5 were investigated.
The following results were obtained
1) The increase in NaOH content had good effects on throwing power, but no good on current efficiency and prevention of embrittlement.
2) NaCN content had little effects on current efficiency and throwing power. However, its content as low as 53g/l among baths containing NaCN 24.5g/l had good effects on prevention of embrittlement.
3) Low current density had good effects on current efficiency and throwing power. Whereas, considerably high current density had good effects on prevention of embrittlement.
4) The optimum temperature of baths for high throwing power was 25°C and high current emciency or preventive power of embrittlement was obtained at 40°C.

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It was reported in the previous paper that the anodic coating of aluminum, which had been prepared from sulfo-salicylic acid or sulfuric acid solution as electrolyte, showed amorphous Al₂O₃, but at was proved by X-ray diffractiometry to be changed to γ-Al₂O₃ by heating at 800°C.
Various methods have been proposed in order to investigate the atomic bond an the amorphous state. It is believed that fluorescent X-ray method would be available for measurement of co-ordination numbers of atoms. Then, the authors attempted to determine chemical shift of the co-ordination numbers of Al and S in the above amorphous Al₂O₃ for measurement of these numbers.
The results obtained were as follows:
1) Both of aluminum atoms in the anodic coatings prepared from sulfo-salicylic acid and sulfuric acid solutions as electrolytes, had co-ordination numbers of 6-fold or 4-fold like that of γ-Al₂O₃. It proved that there was no significant difference in appearance between the both coatings.
2) The co-ordination numbers of sulfur in both of the anodic coatings were measured in the same manner as in aluminum. It was shown that the bonding of sulfur atoms was similar to that of SO₄^2--bond.

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In practical dyeing of anodic coating, it is very often evident that the proceeding of dyestuff adsorption is not satisfactory. It is apparent that the trouble is resulted from the blending of various kinds of ions in the dye bath.
The effects of blending of anodizing components and additives for controlling pH on dyestuff adsorption of anodic coating were studied.
As the results, it was found that the amount of adsorption was decreased with the increase in the amounts of anodizing components and additives. In particular, the effect was greater by blending of organic acids.
Furthermore, the effects of elimination of obstructive ions on the adsorbed amount and concentration of dyestuff were studied. When aluminum ions were precipitated as hydroxide, a larger amount of dyestuffs were adsorbed by aluminum hydroxide; and when sulfate ions were removed by precipitating as barium sulfate, the adsorption of dyestuffs was almost recovered.

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The authors could not prepare an electroless plating bath containing sodium hypophosphite as a reducing agent for depositing iron, but they prepared and classified some kinds of electroless plating baths containing that agent for depositing Ni-Fe-P alloys.
The relation between conditions of baths or the rates of deposition and the compositions of alloys was studied in detail on two kinds of baths, ammoniacal alkaline citrate bath (A-C) and caustic alkaline citrate bath (C-C).
As the results, the conditions optimum for stable and practical baths were obtained as follows:
Ammoniacal alkaline citrate bath (A-C) Caustic alkaline citrate bath (C-C)
FeSO₄+NiSO₄ 0.1mol/l 0.1mol/l
NaH₂PO₂ 0.2mol/l 0.2mol/l
Na-citrate 0.15mol/l 0.25mol/l
(NH₄)₂SO₄ 0.50mol/l -
H₃BO₃ - 0.50mol/l
pH 10 (NaOH) 9 (NaOH)
Operating temperature 90±1°C 90±1°C
The plating rate in A-C Bath was usually high and the both contents of iron and phosphorus in the deposited film were low.
On the other hand, the plating rate in C-C Bath was relatively low and the both contents of iron and phosphorus in the deposited film were high-The composition of the deposit was easily controlled by the ratios among metallic salts in the bath.

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