The solubility of anodic oxide films formed on aluminum in sulfuric acid solutions was studied by measuring transient anode potential observed by the change in anodizing current and temperature and concentration of electrolyte during electrolysis.
The results obtained were as follows.
1) Important factors affecting the transient anode potential during electrolysis were concentration and temperature of the sulfuric acid solution.
2) When aluminum was anodized in sulfuric acid solution at a constant current density, a linear relationship was found between the logarithmic value of anode potential and the time of electrolysis; the constant ratio between the two was assumed to be k.
3) Since it is well known that the thickness of the barrier layer on the anodic oxide film was proportional to the cell voltage in the ratio of 10Å/V, k is considered to correspond with the constant rate of dissolution of barrier layer into the electrolyte.
4) When the concentration of sulfuric acid was kept constant, Arrhenius' Plot was obtained between log k and 1/T (inverse number of absolute temperature of the electrolyte) and the activation energy of anodic dissolution of the barrier layer was determined to be 0.44eV by calculation.
5) When the temperature of electrolyte was constant, log k was found to be proportional to log C (logarithmic value of concentration of sulfuric acid) in the constant ratio of 0.81.

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In this paper, there is reported on the studies about chromizing and sintering processes of iron green compact by pack treatment on addition of NH₄Cl.
The results showed that it was possible to carry out sintering together with chromizing at the same time even at 1050°C, lower than the normal temperature for sintering. A larger depth of chromium penetrated layer was obtained by the addition of NH₄Cl to the penetrants.
The results obtained were summarized as follows.
(1) In low green density (5.32g/cm³) compact the optimum blending ratio of components of penetrants was Cr:Al₂O₃:NH₄Cl5:5:1 by weight. The addition amount of NH₄Cl should be less with the increase in density.
(2) The depth of chromium penetrated layer increased with the rise in treating temperature.
(3) The depth of chromium penetrated layer increased with the decrease in green density. It seemed that gas penetration was superior to solid diffusion for low green density.
(4) The depth of chromium penetrated layer parabolically increased with the increase in treating time.
(5) The effect of sealing of pores can be expected for higher green density.

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Effcts of the crystal orientation of substrates on the nucleation of tin were studied in relation to the electrodeposition of tin from stannous sulfate bath on steel sheet having large crystals or single crystals.
When specimens were electrodeposited after dipped in nital and picral, the nucleation was predominant on (111) plane of the steel sheet having preferred orientations of (111) and (100); and was predominant on (110) plane of the sheet having preferred orientations of (111) and (110).
On the contrarary, the steel sheet after dipped in nitric acid solution showed more nucleation on (100) rather than (111), when it was deposited after observation of orientation by etch-pit method.
The difference in nucleation degree between the above two solutions was found to be prominent for such low current density as 1A/dm².
Effects of pretreatment of substrate in alkaline or acid solution were also investigated to clarify the influences of passivity and roughness of the substrate planes on the nucleation.

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Studies were made on sliding wear of a deposited metal, in particular, a metal comprising low carbon steel, and the relation between the wear and welding conditions was determined.
As the results of observation, it was shown that the wear resistance of the sliding surface was higher in heat-affected zone than in finish welding zone. The effects of bead and sliding direction on the wear seemed to be weakened when they ran in parallel each other. These phenomena were most prominently observed in the sliding surface of finish welding zone.
The effect of number of deposited metal lyers on the sliding wear was studied during experiments. It war found that the amound of wear loss slightly increased with the increase of the number of layers, because the materials of metal layers used in the experiments did not cause dilution phenomena of alloying elements in welding.
In reference to the wear characteristic curve obtained throughout the experiments, wear mechanism was discussed particularly in the areas where the increase of wear loss was distinctly different from that in other areas. Oxidation of the metal was observed in the area of mild wear. However, in the area of maximum wear loss, the occurrence of the loss was mainly due to scratches or scourings produced by adhesion. Moreover, in the area where the wear loss decreased under severer conditions, there was observed metal transfer by strong adhesion.

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Many kinds of composition for zincate solution have been published. However, the authors presented the following equation in accordance with the results of their experiments.
X=αY2/3
where X: mol/l of ZnO or Zn (OH)₂
Y: mol/l of KOH or NaOH
A zincate solution of which the value of α is less than 2, may be prepared. However, the solution of which α is more than 10, was generally stable. For instance, the zincate snlution (α=10), containing 10g/l of ZnO and 100g/l of NaOH, was desirable for electroplating bath.
Cathodic current efficiency of the zinc plating is very low, it is now prepared from cyanide zinc plating bath, from which NaOH is removed. However, the current efficiency gradually increased with the addition of NaOH to the bath and it finally reached nearly the maximum value at 80g/l of NaOH.
Cathode current efficiency of zincate bath, composed of 10g/l of ZnO and 100g/l of NaOH was still relatively high, but the deposit from it was very rough. However, the roughness of the deposit was improved when a small amount of NaCN was added to the bath.
As the results of these experiments, it can be concluded that the fundamental composition of cyanide zinc plating bath now prevailing is composed of zincate solution and NaCN may be assumed to be merely an addition agent.

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