In case of coating with water soluble acrylic resin paints on aluminum anodic oxide film, dip-coating method was applied to investigate the film in transition state under the following conditions: Withdrawal velocity W_w=1.17-100cm/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 by the above experiments: (1) When a vertical plate was lifted at a constant velocity from the stationary liquid, the film thickness on the plate was approximately equal to the theoretical value, h_th=C_thx1/2 when the withdrawal velocity was 100cm/sec., which was the maximum during experiments. (where C_th=√ρg/μ·1/t, t: time for solidification, g: gravitational acceleration, x: distance from the upper edge). (2) The relation between V_w (withdrawal velocity) and C_ov/C_th was approximately expressed by an exponential function: when V_w=100cm/C_th, C_ov/C_th=1.0, V_w=1.17, C_ov/C_th=2.5. (3) The relation between μ/ρ (viscosity/density of paint) and n was approximately expressed by an exponential function: when μ/ρ=0.51, n=0.31, μ/ρ=0.21, n=0.51. (4) The states of film adhered to the plate were divided into two kinds: transition and stationary states. When the withdrawal velocity was as low as 1.17-2.5cm/sec., the relation between the two states was discontinuous.

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Nebulous crystals formed in nickel films in early stage of deposition were studied by electron microscopy. The nickel film was roughly divided into two parts by the bright field image of electron microscope: one was a nebulous part containing a small amount of phosphorus, and the other was a black contrast part due to Bragg's reflection containing almost no phosphorus and with normal lattice constant of nickel. Even if the black contrasts were not observed under a certain Bragg condition, it was proved by varying the Bragg condition that there existed many fine crystals with normal lattice constant of nickel in the nebulous films. Most of the above fine crystals had (211) orientation, and other crystals of different orientations developed with the progress of time. These crystals of (211) orientation were positioned at angles of 120° each other on the plane of specimen. Many planar defects, which seemed to be microtwins or stacking faults, were observed in the crystals of (211) orientation.

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Diffusion couples of Fe-Cr, which mean electrodeposited chromium on electrolytic iron, were studied. This paper describes the effects of temperature and duration for heat treatment on composition, structure, hardness, etc. of the diffusion layers formed. The results were summarized as follows. The chromium content of diffusion layers heat-treated at 600°C was found to be 85-90%. It was also found that chromium content on iron side of the layers heat-treated at 800°C was 25-30%. The X-ray diffraction patterns revealed that the former layer was a Cr-rich solid solution and the latter layer was an α Fe-rich solid solution. The results of hardness measurements showed that the layer formed at lower than 800°C was a Cr-rich layer, having a very high hardness such as H_k=1000.

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The authors examined the changes in number of crack meshes, crack width, plateau size, etc. of a part of chromium deposit, which had been subjected to sucsessive electrolytic etching. The examination was conducted by a serial photomicrography. The following results were obtained. The increase in number of crack meshes and the decrease in plateau size of chromium deposit electrolytically etched were proportional to a certain unit thicness of the deposit; this phenomenon reveals that the presence of cracks of chromium deposit was separated by unit thickness of the deposit, which is referred to as the “thickness of unit crack layer”, hereinafter. The “thickness of unit crack layer” was thinner when the cracks were more dense, but was thicker when the cracks were sparser. Moreover, it was related with the “critical thickness” observed in the measurement of the stress of chromium deposit. When the etching was further promoted, each of the number of crack meshes and plateau size tended to a constant value, at which the thickness was several times as large as that of the “thickness of unit crack layer”.

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The effects of rectified waves on properties of platings obtained from silver cyanide baths were studied. The rectified waves applied were smoothed direct current (F=1.0), single-phase full-wave rectification (F=1.22), and single-phase half-wave rectification (F=1.73). The following results were obtained by examination. (1) It was found that the throwing power largely depended upon the variation of polarization after discussing the relation between the form factor and the bath voltage. (2) Orientation was not observed by X-ray diffractiometry in brightless silver platings deposited in smoothed direct current, single-phase full wave rectification, and single-phase half-wave rectification. (3) Orientation was observed on (220) and (200) faces of the bright silver platings obtained in singlephase full-wave rectification under current densities of 0.5 and 3Amp/dm², respectively. The appearance of the plating obtained in smoothed direct current or single-phase full-wave rectification under a current density of 1Amp/dm² showed mirror-like luster; while, the appearance of that obtained in single-phase half-wave rectification showed mirror-like luster under higher current densities. (4) it was shown by electron microscopy that hexagonal pyramids were observed in the brightless silver platings obtained in single-phase full-wave rectification under low current densities; while, the platings obtained in single-phase half-wave rectification showed triangular pyramids under low current densities and hexagonal pyramid layer. under high current densities, on which cubic deposits were observed.

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