The effect of inorganic additional substances on the coated films was investigated in order to obtain the anti-abrasion precoated steel sheet having good formability. The finely grinded glass fibers and glass flakes were found to be very effective for the above mentioned purposes, but other inorganic materials such as SiO₂ powder or CaSiO₃ powder afforded only surface-hardening effect of precoated films. Almost all kinds of paints except those composed of fluorocarbon polymers were applicable for this anti-abrasion precoated steel sheet, and the effective content of the glass fibers or glass flakes in paints was found to be 15-20%, considering the surface hardness and the formability of the precoated films and the coating workability in the continuous coating lines.

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Steel bar was boronized in air by reducing the fused borax with molten aluminum on the surface. The boronized layer was thicker on treating for longer time under higher temperature. According to the treating conditions, the composition of the boronized layer was varied from Fe₂B only to FeB and Fe₂B. Even the treating at 800°C, the sound boride layer was formed and the vickers hardness was 1800-2000kg/mm² on FeB layer. As the reduction of fused borax with molten aluminum was fast enough to supply boron to the surface of steel, the rate of growth of boride was determined by the diffusion of boron in steel.

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Pulsed current electrolysis has been applied for the electrodeposition of silver from a silver-ammonia complex bath consisted of AgNO₃, NH₄OH and NH₄NO₃ and also from a conventional silver cyanide bath. The surface morphology of silver deposits was studied by photomicrography and the orientation indexes of the deposits were determined by an X-ray diffraction method. The surface morphology and crystal structure of the silver deposits were found to be closely related to the cathodic overpotentials established under the pulsed current electrolysis. In case of the deposition of silver from the silver-ammonia complex bath, the morphology of the deposits obtained by the pulsed current electrolysis does not seem to differ significantly from that of the deposits plated by the ordinary D.C. method. Changes in the preferred orientation of the silver deposits, however, were closely related to the pulsed current density and pulse-on time, thus the development of the fiber structure of silver deposits from these baths depended on the mode of pulsed current electrolysis. Smooth and fine grained deposits were obtained from the silver cyanide bath by the pulsed current electrolysis with a pulse-on time in the range of 0.1 to 10 milliseconds and at an average current density of 1 Adm^-2. The adsorption of cyanide ions seemed to play an important role in the deposition of silver under pulsed current electrolysis.

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The crystallographic and magnetic properties of chemically plated cobalt alloy films, codeposited with nickel and/or tungsten were investigated for the purpose of developing the thin-films of high density recording medium with 600-700 Oe coercive force. The optimum conditions of ammonia alkaline malonate-gulconic acid plating bath for this purpose were determined for Co-Ni-P and Co-Ni-W-P thin-films. The c-axis of hcp structure of Co-Ni-P films was strongly oriented to horizontal axis of the substrate, and the amorphous fcc structure was introduced when the molar ratio of Ni²⁺/(Co²⁺+FNi²⁺) in the bath conditions became higher than 0.7. In the case of the Co-Ni-W-P film, the c-axis of hcp structure was also strongly oriented to the horizontal axis. In the case of Co-W-P film, the c-axis of hcp structure was oriented from horizontal to perpendicular axis of the substrate with the increase in Na₂WO₄ concentration in the bath. The squareness of the films was improved to a greater extent when the substrate of chemically deposited Ni-P film was used instead of copper substrate.

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