Bright tin-lead alloys containing 100-50% of tin were electrodeposited from a phenolsulfonate bath containing a condensation product of acetaldehyde with o-toluidine, a non-ionic surface active agent, and acetaldehyde. An alloy deposited from the bath at 2-5Amp/dm² had a smooth surface and a good luster. The composition or lead content of the deposited alloy was nearly equal to that of the bath over a wide range of current densities from 0.25 to 10Amp/dm². The additives showed brightening effect on a single tin deposit, but not on a single lead deposit; and well-defined orientation of tin crystals was recognized in the X-ray diffraction pattern of the panels deposited from the bath containing brighteners. Therefore, the brighteners seem to interact mainly with tin during electrodeposition. Anodic dissolution of alloys was smooth, and no passivation occurred in the bath. The throwing power of the bath was in the same degree as that of a fluoroborate bath.

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Several double anodic oxidation coatings were formed on aluminum under different anodizing conditions (such as bath temperature and current density) and the effiects of anodizing conditions on surface properties and structure of coatings were studied. A hard anodized coating of excellent surface properties was obtained under a constant current density of 4Amp/dm², in which the 1st layer (upper layer) was formed by the ordinary anodizing method (20°C, 30min.) and the 2nd layer (lower layer) was formed by the hard anodizing method (-5°C, 30min.). In particular, the coating formed by the 1st anodizing at 10°C for 30min. and the 2nd anodizing at -5°C for 30min. showed few cracks, a very plain surface, and a high wear resistance. When the bath temperature was constant at -5°C, the coating formed under a low current density in the 1st anodizing and under a high current density in the 2nd anodizing showed a wear resistance higher than that formed by the reverse order of treaments. However, the double anodic oxidation coatings under differrent current densities showed little differences in wear resistances according to the order of treatments for the 1st and 2nd processes; in contrary to the same conditions (with respect to the order of treatments) in different bath temperatures. The effect of structure of the cell on wear resistance was pursued. The coating formed under the condition for a large cell size in the 1st layer and a small cell size in the 2nd layer showed a remarkable decrease of wear resistance near the interface of the two layers. On the contrary, a high wear resistance was obtained by the reverse condition; that is, the condition for a small cell size in the 1st layer and a large cell size in the 2nd layer.

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The authors studied the properties of aluminum diffusion coated layers on stainless steels: SUS 430, SUS 304, and SUS 321. The results obtained were as follows. (1) The aluminum diffusion coated layer consisted of an additive layer and a diffusion layer. The additive layer having an almost uniform aluminum concentration, was composed of Fe₃Al and a solid solution of component elements; it was observed that it had a structure consisting of columnar and ununiform grains. In addition, the additive layer of SUS 321 (about Hv 800) was much harder than those of SUS 430 (about Hv 400) and SUS 304 (about Hv 500). (2) The variation in aluminum concentration of diffusion layer was continuous in SUS 430, but those in SUS 304 and SUS 321 were discontinuous. The structure of diffusion layer consisted of gross grains in each kind of steels. (3) Tensile stress appeared in the additive layer of each aluminum diffusion coated stainless steel. The decreasing order of the tensile stress was arranged as follows: SUS 430>SUS 304>SUS 321. (4) There was a tendency of cracks on the surface as follows: The size of crack was proportional to the tensile stress and the thickness of additive layer. (5) The amount of foreign matter adhered to the spots of high aluminum concentration on the surface increased with the rise of temperature for diffusion coating.

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The authors studied the oxide films of aluminum diffusion coated stainless steels: SUS 430, SUS 304 and SUS 321, which were formed by oxidation of respective diffusion coated layers in the air at high temperatures. The studies were made by transmission electron diffraction, X-ray diffraction, X-ray microanalysis and scanning electron microscopy. The results obtained were as follows. (1) The oxide film formed on aluminum diffusion coated SUS 430 by oxidation at 1, 050°C for 2min, was mainly composed of α-Al₂O₃, and the oxide films of the other two kinds of steels were mainly conposed of α-Al₂O₃. (2) It was found that the oxide films of aluminum diffusion coated stainless steels, formed by oxidation at 1, 050°C for 1hr., contained a small amount of (Cr, Fe)₂O₃, which seems to be formed in defective parts of oxide films composed of α-Al₂O₃ or γ-Al₂O₃. (3) With the decrease of aluminum concentration on the interface, (Cr Fe)₂O₃ as well as α-Al₂O₃ was formed followed by the formation of FeO⋅Cr₂O₃. (4) When each kind of aluminum diffusion coated stainless steels was oxidized at 1, 050°C, the critical aluminum concentration was about 2 wt% on the interface between the matrix (for forming the oxide film mainly composed of α-Al₂O₃) and the oxide film. (5) The oxide film of aluminum diffusion coated SUS 321 was more resistant to thermal shock than that of diffusion coated SUS 430.

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The effects of electric current and voltage on aluminum integral coloring in oxalic acid and malonic acid solutions were examined. The results obtained were as follows. (1) When a constant current was applied, integral coloring occurred at high voltages, but not at low voltages. The “coloring voltage” was over 80V. (2) In case of aluminum anodizing by using a high constant voltage in dilute solution, the specimen was colored in a short time (60sec.) and no change of the color was observed for a long (10min.) of electrolysis. (3) The current density increased with the rise of bath temperature even though at low voltages; however, the integral coloring of aluminum did not occur, except in the case of the following (4). (4) Aluminum was colored when a peak of current was present on I-t curves at a constant voltage. (5) The surface roughness of aluminum base increased with the increase of applied voltage: that is, the surface roughness was higher at higher applied voltage.

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