The mechanism of initial formation and growth of Au plate crystals on Fe single crystals or polycrystals electrodeposited from hydrochloric auric chloride bath was examined by electron microscopy.
The results obtained were as follows:
(1) The population of nuclei or micro-particles of Au electrodeposited in the initial stage of deposition was about 3×10¹¹cm^-2. On further deposition, Au micro-crystals were connected one another by feather-like thin plate crystals and were formed into islandshaped or net-work structure.
(2) The Au micro-particles of scores of Å in size gave a spotty diffraction ring pattern and the Au plate crystals gave distinctly arced or spotty arced diffraction pattern.
(3) The stable coherency between the Au plate crystals and Fe substrate was formed when the surface coverage was about 80%. The coherency was as follows:
(001)Fe//(001)Au [110] Fe//[010]Au}
(4) The plate crystals at the stage of the surface coverage of 85% had many sub-grains of 150-400Å in diameter. With the progress of electrodeposition, the diameters of the sub-grains were increased.
(5) In the plate crystals, there were some Au particles having crystal orientations different from those of the plate crystals.
(6) In the plate crystals, there were observed many microtwins, which contributed to the relaxation of strain in Au plate crystals.

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The baths containing a mixture of silver cyanide and stannous pyrophosphate were prepared for studying improvement in anti-tarnish property of Ag alloy deposits. The bath compositions and electroplating conditions for obtaining the deposits having about 10% of tin content and the properties of the deposits were examined.
The results obtained were as follows:
(1) A bright Ag alloy deposit (80-95% Ag) was obtained with stirring from a bath containing free K₄P₂O₇ 75-150g/l, free KCN 15-25g/l, Sn²⁺7-15g/l, Ag⁺8-16g/l and H₂O₂ (30%) 1-3m^l/l by electrolysis under cathodic current density of 0.3-1.0Amp./dm².
(2) The bath became turbid and precipitate was formed with the lapse of time. However the process could be retarded to some extent by addition of a small amount of H₂O₂.
(3) As compared with single Ag deposit, Ag-Sn alloy deposits had higher hardness and lower anti-tarnish property.

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In the previous paper, there were reported the studies on electroless Ni-Fe-P alloy plating bath reduced by sodium hypophosphite.
This paper reports on properties of the deposits obtained from the previous plating baths. The following results were obtained.
(1) In the deposits from the caustic alkaline citrate bath at pH=9 (C-C-9), nickel component was in amorphous state and iron consisted of fine crystals of α-iron. Whereas, in the deposits from the ammoniacal alkaline citrate bath at pH=10 (A-C-10), nickel component consisted of fine crystals and iron was nearly amorphous. In addition, in the deposits from the ammoniacal tartrate bath at pH=9 (A-T-9), both nickel and iron were in nearly amorphous state.
(2) Types of the baths were arranged in descending order of the brightness of deposits as follows:
A-C-10>A-T-9>C-C-9
The brightness was decreased with the increase of iron content in each deposit.
(3) The micrographs of the cross-sections of deposits revealed that lamellar structure was detected with the decrease of iron content and it was changed to columnar structure when iron content was higher than 50%.
(4) The hardness of deposits was lower with the increase of iron content.
(5) The surface of deposits was likely to be converted into passive state with the increase of iron content.

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Limited thickness of the single crystal growth of electrodeposited gold layers on (110) plane of copper was examined by means of X-ray. In addition, the microstructure of gold films electrodeposited on (001), (110), (111), and (123) surfaces of copper was examined by electron microscopy and the selected area diffraction. The results were compared with those published for gold films formed by vacuum evaporation. Considerable similarities were found between the above two types of films.
Many {111} twins were observed in all types of gold films electrodeposited on copper single crystals and the directions of the twins conformed to the crystallographic relation. The density of these twins was of the order of 10⁸/cm²-10¹⁰/cm², their width was in the range of 80-2, 000Å, and their length was in the range of 100-5, 000Å.
Double positioning boundaries were observed in the films deposited on (111) and(123) surfaces. In the thin film deposited on (123) surface, many dislocations were observed around the double positioning boundaries, and the dislocation densities were of the order of 4×10⁹-1×10¹⁰/cm².

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The properties of the cathodic film obtained from aqueous solution of single chromic acid and that solution containing sulfuric acid or acetic acid were studied, and the following results were obtained.
(1) The appearances of the cathodic films obtained from aqueous solution of single chromic acid and that solution containing acetic acid were much different according to the conditions of electrolysis.
(2) The burning of the film obtained from that solution containing sulfuric acid depended upon the temperature of the bath. At lower temperatures, it consisted of fine particles and at higher temperatures, it was a mere convexity.
(3) Diffracted ray was not observed by X-ray diffractiometry from bright chromium plating film; otherwise, the intensity of the ray was very weak showing the incomplete development of crystals.
(4) The descending order of the intensities of diffracted rays through the platings obtained from each of the above 3 kinds of baths under the current density of higher than 200Amp/dm² was arranged as follows: [110]>[200]>[211]

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The properties of sheet steels plated with vacuum evaporated zinc coatings depend upon coating conditions, which have not been thoroughly studied.
The authors made basic studies on vacuum evaporated Zn coatings such as coating conditions, film structures, special pre-treatment of substrate.
This paper describes the results obtained concerning appearance and morphology of vacuum evaporated zinc coatings, which have a close relationship to the mechanism of film growth.
(1) The temperatures of the substrate and evaporating source on evaporation had great effects on the deposition of zinc and the morphology of film surface. The appearance of coatings depended upon the surface morphology.
(2) The crystal orientation of Zn film depended upon the temperature of substrate in the range of deposition rate (Vd) of 0.5μ/min.>Vd>0.05μ/min.
As the results of experiments, the range of substrate temperature (Tp) was broadly divided into the following three divisions: Tp<50°C, 60°C<Tp<160°C, and 170°C<Tp.
(3) The grain size of Zn crystals was larger with the increase in film thickness when the substrate temperature was lower than 160°C. The size was larger with the rise in substrate temperature for the same film thickness. The crystal orientation was varied according to the film thickness when the substrate temperature was higher than 170°C.

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