The leveling action of bright acid copper plating was investigated by using the Hull Cell test panel and the diagrams which universally show the relation between the geometric leveling power and the plating thickness as a function of the angle of the groov. The leveling powers were estimated at the various points of the Hull Cell test panel by measuring the surface roughness before and after plating and the plating thickness evaluated from the primary current distribution. The surface roughness was measured with the surface roughness tester. In spite of these easy and simple measurements, the leveling action in bright acid copper plating could be known universally on the diagrams as a function of the plating thickness, current density and the surface microprofile. Therefore, this method for the measurement of leveling was considered to be practically useful.

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Simultaneous impregnation of mild steel with boron and silicon was conducted by electrolysis in a salt bath consisting of sodium metasilicate, borax and carborandum. Four types of microstructures were found in diffusion coatings as a result of changing the composition of the salt bath. In the first type, the outside layer of the diffusion coating consists of wedge-shape FeB which embraces small particles of αFe-Si solid solution, while the inside layer consists of Fe₂B and lumps of αFe-Si solid solution. In the second type, the outside layer consists of Fe₂B which similarly embraces small particles of αFe-Si solid solution, the intermediate layer of thick layer of αFe-Si solid solution, and the inside layer of granular shape of Fe₂B contiguous to substrate. In the third and fourth types, the coatings consist of dense or porous layer of αFe-Si solid solution and of granular shape of Fe₂B contiguous to substrate. In all cases electron probe micro-analysis showed no solubility of Si into Fe-B compounds.

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Iron-Chromium alloys of a wide range of composition have been electrodeposited from a 40% (v/v) dimethylformamide bath containing FeCl₂ and CrCl₃ with a total concentration of 0.8M. The deposition potential of chromium in the dimethylformamide bath was found to be less noble than those of hydrogen and iron, and the maximum current efficiency of chromium deposition was obtained at higher current densities than that of iron deposition. Chromium content in the Fe-Cr deposit increased with increasing molar ratio of Cr/Fe in the alloy bath and a smooth, white-gray and bright deposit was obtained under these conditions. When the electrolysis was carried out at the current densities larger than the diffusion controlled current of iron deposition, chromium content in the Fe-Cr alloy deposit was found to be more than 15%. Both the current efficiency of chromium deposition and the chromium content in the alloy deposits decreased with increasing temperature up to 60°C, but the composition of Fe-Cr alloy was found to be insensitive to the change in pH 1 to 2.5. Fe-Cr alloys having higher Cr content were obtained at temperature below 20°C, but the alloy deposit was found to be matt, rough and brittle. The microscopic examination of the Fe-Cr alloy deposits revealed that a spherical nodular growth was observed on the initial smooth layer and the roughening of the surface was pronounced with an increase in the deposition time. Fe-Cr alloy deposits (10-60% Cr) up to about 20μm can be obtained from a 40% dimethylformamide bath (pH 1-2.5) with the Cr/Fe molar ratio of 0.5/0.3-0.6/0.2 using the current densities of 50-500mA·cm^-2 at 20-40°C.

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This report deals with current distribution and formation of anodic coatings on aluminum in a horizontal type aondizing cell in 0.2M NaOH-H₂O₂ bath by D. C electrolysis at constant voltage. The experimental results showed that the current distribution was more uniform as the bath voltage and H₂O₂ concentration were higher and bath temperature was lower. The thickness of the oxide films decreased with increasing dissolved aluminum ion in the bath. Powdery oxide films were formed when agitation of the electrolyte was insufficient.

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