Gold was electrodeposited from KCN bath on spheroidized 0.88% carbon steel. The nucleation of cementite region occurred later than that of ferrite region, and the number of nuclei formed on the former was smaller than that on the latter. However, the lag-time for the nucleation of cementite was shortened and the number of nuclei of these regions increased by the electrodeposition under a high current density. The nuclei of the both regions grew up independently with each other; they formed an insular and net-work structures, and finally, made up continuous films. The electron diffraction pattern of Au plate crystals electrodeposited on ferrite under a low current density gave rise to an N-pattern and a weak Debye-Scherrer ring; while, that of Au plate crystals on cementite consisted of only a Debye-Scherrer ring. The electrodeposition under a high current density was effective for improvement in Au film's epitaxy, and the Au plate crystals formed on ferrite made up good single crystals; while those formed on cementite had a tendency to be arranged in one orientation.

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Martensite was obtained by quenching of 0.88% carbon steel in iced water. The growth process and structure of Au films electrodeposited on martensite from KCN bath were studied by transmission and scanning electronmicroscopy. The Au plate crystals inherited a morphology from martensite substrate. The Au plate crystals on a leaf of martensite had a tendency to be arranged in one orientation, but a strong Debye-Scherrer ring was observed in the selected-area diffraction pattern of these crystals. The maximum numbers of nuclei on martensite were about 3×10¹¹cm^-2 in electrodeposition under 0.5 Amp/dm² and 8×10¹¹cm² in electrodeposition under 15Amp/dm². These values were larger than those on annealed pure Fe so that it would be suggested that the strained fields around the lattice defects on the martensite surface were sites effective for nucleation. Secondary nucleation occurred in the electrodeposition under a high current density, and the particles, thus formed secondarily, contributed to the two-dimensional growth of Au films.

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Nickel-chromium alloys were electroplated from 50% (v/v) of dimethyl formamide bath principally composed of nickel and chromium (III) chlorides. Typical bath compositions for plating of nickelchromium alloys were as follows:
NiCl₂ x mol; CrCl₃ y mol (x+y=1.0mol); NaCl 0.5mol; NH₄Cl 0.5mol; H₃BO₃ 0.15mol; pH 1.8; Temperature 25°C. The cathodic polarization curves and current efficiencies in electrodeposition of nickel, chromium, and nickel-chromium alloys were measured to clarify the mechanism of electrodeposition of alloys. Limiting current densities depending on CrCl₃ (III) concentration were observed in the nickel-chromium alloy baths as well as in CrCl₃ bath. The electrodeposition could be conducted over the whole range of 0-100% of chromium content of the bath by proper selection of the metal ratio and current density (2-25 Amp/dm²) in the bath. The nickel content of alloy deposit was found to be always higher than the corresponding metal ratio in the bath. Such results could be explained by the normal codeposition theory of alloys. The nickel-chromium alloy deposits showed good adhesion to copper and steel. However, cracks were observed in the alloy deposits as well as in the nickel deposits obtained from dimethyl formamide (DMF) baths. It was shown by X-ray diffraction analysis that as-plated alloy deposits have an amorphous structure; and well-defined X-ray diffraction patterns were obtained when the deposits were heat-treated at 800°C for 1hr. in H₂ current.

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The processes of electroless plating of nickel and cobalt from the baths containing hypophosphite as reducing agent are well established. Whereas, there have been no reliable reports on electroless plating of iron from this type of baths. The problem was solved in the present study using a strong alkaline solution containing high concentration of potassium sodium tartrate as complexing agent. Practically available iron coatings containing about 0.2% of phosphorus were deposited only by a autocatalytic electroless plating reaction. Phosphor bronze, copper, iron, and copper coated with electroless-deposited nickel were used for substrates, which were beforehand sensitized by dipping in palladium chloride solution. It was confirmed by magnetic measurement that the iron coating thus obtained consisted of crystallites of α-iron, though there were no peaks observed in the X-ray diffraction pattern. The deposition rates were very slow on the substrates such as platinum coated with electrodeposited palladium, plastics, and single crystals of magnesia, alumina, and silica. The following metals could be co-deposited with iron from the baths: nickel, cobalt, molybdenum, zinc, cadmium, chromium, and arsenic.

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Copper-SiC alloys were electrodeposited from a copper-fluoborate electrolyte bath containing fine SiC particles suspended by mechanical agitation. The concentration of SiC in the alloys was determined by means of absorption photometry. Uniformity of the dispersion of SiC particles in the deposit and microstructure of the alloys annealed at various temperatures were examined by optical microscope, scanning electron microscope and X-ray diffraction. The relationship between annealing temperature or time versus micro-Vickers hardness of alloys, which is supposed to be proportional to yield stress, was investigated. In addition, abrasion and oxidation tests of the samples were carried out. The results obtained are summarized as follows: (1) The effect of dispersion-hardening was retained up to high temperatures such as 900°C and this was so with the increase of SiC content in the deposits. (2) The abrasion and oxidation resistances of Cu-SiC alloys were higher than those of copper deposit. (3) The recrystallization and grain growth of the matrix in the range of high temperatures were retarded in the presence of dispersed SiC particles.

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