It has recently caused a public trouble that local corrosions frequently appear on the surface of a coiled tape measure, of which the steel surface is coated with a resin called “epicoaton” in trade name. The corrosions appear on the practice of users, though they were not known by the manufacturer.
The cause and prevention of these corrosions were studied and the principal results obtained were as follows:
1) The leading factor affecting these corrosions was initial rusts which were microscopically observed on the coiled surface of the base steel.
2) The use of some inhibitors (such as oleic acid) in descaling process was effective for the prevention of these corrosions.

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The authors intended to conduct the abrasion tests of anodic oxide films on aluminum by a Taber Abraser. However, the abrasive wheels manufactured by Taber Instrument Corp. (such as CS-17) give small wear loss of test pieces and need long times in abrasion measurements. Moreover, their prices are high due to imports, and their consumptions are remarkable.
In this study, the authors selected some commercial grindstones as substitutes of CS-17 wheels and made experiments to determine whether they were actually available for substitutes of CS-17 wheels.
It was also investigated whether the wear properties of hard anodic oxide films can fully be derived from the abrasion tests in deionized water.
The results obtained were as follows:
1) It was found that some commercial grindstones such as WA 120K, PVA c 120-10M, and PVA C 1204W were suitable for the abrasive wheels combined with the Taber Abraser as substitutes of CS-17 wheels.
2) The abrasion resistance tests on the surfaces of films showed that there were little differences in the early stage of abrasion between the films formed at 15 and-5°C.
Whereas, in the abrasions on the metal-oxide interfaces, the films formed at a lower bath temperature were proved to give higher abrasion resistances.
3) The abrasion tests by WA grindstones were conducted in deionized water and the results of good reproducibility were obtained.
4) It was clearly explained that sliding ratio (S) was a certain degree of criterion for abrasion resistance.
5) It was also found possible to determine the abrasion loss by observation of the decrease in film thickness by means of a high frequency thickness meter, because the trail of abrasion was uniform and the initial weight loss was great in these tests by wet process.

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The surface of heat-treated steel has recently been regarded as very important and various atmospheres have widely been applied to its heat-treatments.
In this paper, there are discoussed the behavior of furnace gases and the surface of heat-treated die steel by using the gas decomposed from CH₃OH⋅C₆H₆ mixture, and H₂, Ar, etc..
The results obtained were summarized as follows:
1) CO₂ content decreased and CH₄ content increased in the atmosphere produced from CH₃OH⋅C₆H₆ mixture with the increase in C₆H₆ content of the mixture.
2) The gas decomposed from CH₃OH⋅C₆H₆ mixture, which contained 1-5% of C₆H₆, showed carbon potential of 1.2-1.9% at 950-1, 050°C,
4) The oxide of die steel produced by heat-treatment in the gas decomposed from single CH₃OH was Fe₃O₄, which was supposed to be produced by H₂O (gas) in the atmosphere.
4) The luster of heat-treated die steel also depended upon its roughness.

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As a comlexing agent for cuprous ion, 2, 9-dimethyl-1, 10-phenanthroline was added to the electroless copper plating bath containing EDTA as the complexing agent for cupric ion. The polarization characteristics of the copper electrode in the bath were examined by means of potential scanning method.
The results obtained were as follows:
1) The total polarization curve at 70°C in the bath containing no additives showed a peak on its cathode current curve in the same way as described in the previous paper (at 30°C).
2) However, as would be expected, the peak completely disappeared at 70°C in the bath containing more than 30mg/l of 2, 9-dimethyl-1, 10 phenanthroline; then, it seemed that the mixed potential theory was held over the whole potential range.
3) The copper, which had been deposited under the above conditions, was also improved in its ductility.
4) It seemed that these effects are based on the prevention of copper electrode surface from its oxidation owing to the complexing of cuprous ion with 2, 9-dimethyl-1, 10-phenanthroline and keeping a constant copper surface over the whole potential range.

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In the preceding paper, it was reported that the hardness of anodic oxide films on aluminum increased by heat treatment. In this study, the abrasion resistance of anodic oxide films treated by secondary hardening was measured with Taber Abraser.
The results obtained were as follows:
1) The films heat-treated at 200°C in boiling solution of sodium acetate and zinc sulfate showed the highest abrasion resistance, which was found to be about 10 times as high as that of no secondary hardening treatment.
2) It was observed that the abrasion resistance of anodic oxide films and that of the films treated in boiling solutions of metallic salts increased by heat treatment. It was known that the highest value of the resistance was obtained when treated at 200°C, and the value gradually decreased when the treating temperature was higher than 400°C.
3) It was also observed in reference tests that the abrasion resistance of secondarily hardened films was more than 22 times as high as that of hard chromium deposits.

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