An apparatus was prepared for trial for measuring the frictional force between a ball slider and a plane specimen by means of a strain gauge. By using this apparatus, the authors measured the decrease in coefficient of friction (μ_κ) of clean metal surfaces, which had resulted from their contamination with polar and non-polar organic compounds. At a very early stage of contamination, stick-slip waves appeared in oscillating curves of frictional force scanned with the slider from one to the other end of the specimen; but, smooth curves were finally obtained when the surface was covered with monolayers of organic compounds with the proceeding of contamination. Oleic acid, which had been adsorbed on metal surfaces by vapor condensation, retraction, or Langmuir-Blodgett's Technique, reduced μ_κ of metals in decreasing order of Cu>Fe>Al and stainless steels, which would be explained in terms of the differences in chemisorption. Octadecane also reduced μ_κ; but it had a marked distinction that μ_κ depended on the load of slider. From these points of view, it was proposed that the measuring of the coefficient of friction by using the above apparatus can be applied to determine the cleanliness of metal surfaces.

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Electrodeposition of iron-tungsten alloys from aqueous ammoniacal alkaline tartrate electrolytes is studied by means of electron diffraction of cathode deposits and chemical analysis of the solution sorbed on them. In resemblance to the adsorption of irregular binany system, the metal component of lower concentration in bulk electrolyte is preferentially adsorbed at non-polarized electrode. This paper describes that this adsorption is important in studying induced codeposition. The electrodeposition of crystalline Fe₃W having a non-equilibrium superlattices of DO₁₉ type was found. A geometric requirement for the formation of these crystals was presented. The effect of codeposition of hydrogen on inhibition of this requirement was shown, which accounts for the observed structural transition of alloys prepared under different conditions. The stoichiometry present in the cathode deposits supports the correlation previously proposed between metal composition of electrolyte in the bulk and that at the cathode surface. Qualitative description can be given of the alloy composition using the values of metal composition of ions at the cathode surface and certain reluctance of tungsten in codeposition. This description will be in better agreement with the experimental results on the assumtion that the electrodeposition of tungsten is catalyzed by multiplets of iron atoms deposited in particular geometric structure.

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In “Japanese Industrial Standard”, there is specified that the alkali resistance of anodic oxide film on aluminum shall be indicated by the time (sec.) required for dissolution of the film and exposure of the ground metal by action of the testing solution (10% NaOH); and is also specified that the alkali dropping method shall be applied for the test. In order to get more accurate and reproducible test results, an improved testing method, quite different from the dropping method, was studied by the author. In this improved method, a Monel metal cell fitted with a hard rubber gasket was in close contact with the surface of specimen; and then, the cell was filled with the testing solution. The exposure of ground metal was determined by measurement of a certain value of electromotive force with a self-balancing recorder between the cell and the ground metal. For simpler and more accurate operation, the author designed and practised a new apparatus, which automatically indicates the test results by digital data, according to the results of experiments. In general, in the tests of chemical reaction, the fluctuations of testing temperature must be controlled within a narrow range as possible. In this method, it was possible to maintain the temperature of specimen within the range of 55±0.2°C by touching the back of specimen with water regulated at the testing temperature (35°C). As the results of above improved testing method for various specimens which had been formed under different conditions, the variation of resistance was 5% maximum, showing more accurate and reproducible values.

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The authors have studied anodic oxidation of sintered body of aluminum prepared in nitrogen atmosphere and its formation by using various kinds of forming electrolytes. This paper describes the comparison of electric characteristics between two types of anodized aluminum prepared in nitrogen atmosphere and formed by using two kinds of different forming electrolytes; ammonium borate (NH₄)₂B₄O₇ solution and ammonium dihydrogen phosphate (NH₄H₂PO₄) solution. After formation, the aluminum sintered body was coated with manganese dioxide (Mn O₂) as a semi-conductor. The comparison was made by measuring V-I characteristics, capacitance, tan δ, etc. The results revealed that ammonium dihydrogen phosphate solution gave better effects than ammonium borate solution.

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A dip coating equipment was prepared for the development of a coating method with water soluble acrylic resin paints on aluminum anodic oxide film. Experiments were conducted by this equipment under the following conditions:
Withdrawing speed V_w=0.33-1.67cm/sec., Density of paints ρ=1.00-1.29g/cm³,
Viscosity of paints μ=0.19-0.66 poise, Surface tension of paints σ=32.0-36.4dyne/cm.
The following results were obtained in the range of 10^-3-10^-1 of capillary number. (1) The the-oretical thickness of dip-coated film (h_th) was in good agreement with the following equation of Landau and Levich: h_th=0.944(μV_w/σ)^1/6(μV_w/ρg)^1/2 (2) The thickness of film adhered (h_ov) was expressed by the following equation: h_ov=K. h_th where K is a residual coefficient, which is 0.70-0.84. (3) The film adhered to a vertical plate became thinner with the lapse of time by “running” of the paint, and the “running was continued until the setting of paint occurred by evaporation. The time for setting seemed to be 500-600sec. in these experiments. (4) The residual coefficient of paints used in the experiments was nearly proportional to the value of μ/ρ. (5) The coated surface of test piece showed avery high degree of smoothness. Therefore, the dip coating would be effective in practical application.

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Anodic oxide films on aluminum were formed in 150g/l H₂SO₄ bath under particular electrolytic conditions of temperature, current density, and electric wave form. Then, integral coloring process of the films was investigated by means of electron probe X-ray microanalysis, fluorescent X-ray analysis, optical microscopy, decoloring processes accompanied with heat treatments, ultraviolet and visible absorption spectrum analysis, etc. The following results were obtained: (1) Self-colored films of anodic alumina could also be formed on aluminum in sulfuric acid. (2) The film, which had been anodized on 1100 aluminum by alternating current at 20°C for 40min., was found to contain iron on the boundary between aluminum and the film. (3) The colored films, which had been anodized by three kinds of electric wave forms: AC, DC-PR, and pulse-PR, were supposed to contain sulfur, which was analyzed to affect the self-color of the films. (4) In addition, the mechanism of integral coloring process of the films, which had been colored by electric wave forms such as DC and pulse, was supposed to be due to the defective crystal structure rather than effects of electron. (5) Colors of films were deepened by X-ray irradiation. Among the films, transparent alumina films were converted into light brown colored by X-ray irradiation.

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The authors studied the effects of substrate compositions on the formation of Cr diffusion coated layer by pack process. The substrates used were Ni, 18 Cr/10 Ni/Ti steel, 18 Cr/0.06C steel, 18 Cr/0.09C steel, and 0.15C steel. The results obtained were as follows: (1) In H₂ atmosphere, Ni as a substrate component catalytically promoted Cr deposition and gave larger quantity of diffusion coating and higher Cr concentration of surface as compared with Fe as a substrate component. (2) About 18% Cr as a substrate component increased the quantity of diffusion coating and prevented the rise in chromium concentration of surface at high temperatures, because it gave more increase in diffusion coefficient as compared with 0.15C steel. However, on the contrary, it decreased the quantity of diffusion coating at low temperatures, at which the diffusion coefficient was small. (3) C as substrate component increased Cr concentration of surface and decreased the quantity of diffusion coating, because it decreased the diffusion coefficient. (4) The variation in the quantity of diffusion according to the substrate composition was reasonably explained by assuming that Cr deposition rate mainly depends upon the difference between equilibrium Cr concentration of surface and Cr surface concentration.

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