An examination was made of the influence of some deposition parameters on coating structures and properties. The Sn films deposited on steel substrates were prepared using a do ion plating apparatus. The deposition parameters are distance between substrate and evaporation source, substrate temperature, deposition time, negative bias voltage, and argon pressure for glow discharge. Film thickness measurement was made by optical microscopy. The structures and surface morphology of the films were examined by scanning electron microscopy and X-ray diffraction. The corrosion resistance of the films was evaluated by salt spray testing. The adhesion of the films was estimated by the force required to strip the film off the substrate. From these results, the film thicknesses decreased with increasing distance between substrate and evaporation source, and also decreased with an increase in argon pressure for glow discharge. Inversely, the film thicknesses increased with increasing substrate temperature, deposition time, and negative bias voltage. An X-ray diffraction study indicated the presence of alloy layer for substrate temperatures above 150°C. The corrosion resistance of the ion-plated Sn films was also affected significantly by the plating conditions. Ion-plated films showed excellent adherence as compared with the films obtained by conventional vacuum deposition method.

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The properties of the anodic oxide films on aluminum alloys and on those which were partially clad with iron were investigated in alkaline baths containing hydrogen peroxide. The distribution of impurities in the films was examined by electron probe microanalyzer (EPMA). The results obtained were as follows: (1) Generally, the anodic oxide films of wrought aluminum alloys were thicker than those of cast alloys. An alloy containing copper (2017) forms the thickest film of all wrought aluminum alloys. (2) In anodizing an aluminum alloy containing magunesium (5052), the voltage increase was so rapid with the lapse of time that the anodizing was impossible to carry out. (3) The aluminum alloy sheet partially clad with iron (area ratio of Al/Fe: 100/1) formed an anodized film having almost the same film thickness as those of bare aluminum sheets. (4) It was considered that a brown film produced on the alloy containing copper (2017) was caused by the immigration of copper into the anodic oxide film from the alloy. Copper was found to exist near the outer surface of the anodic oxide film.

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The effects of anions in chromic acid bath have been investigated on the appearance of deposits and current efficiency. Effective anion species in chromium plating were found to have an ability either to penetrate into the cathodic film or to dissolve it. From the values of pH in the vicinity of the cathode and of pK of anions, neutral anions such as SO₄^2- and F^- are supposed to penetrate into the cathodic film and acidic (pK<2) anions such as HSO₄^-, HMF₆^X-1 and HF₂^- to dissolve the film. These anions, therefore, play an important role as catalytic anions in chromium plating. However, if the bath does not contain enough amount of these anions or pH value of the bath is low because of the low concentration of CrO₃, the neutral anions cannot readily penetrate into the film, while the number of acidic anions decreases. Excess of anions or low pH values of the bath, on the other hand, accelerate unnecessarily the penetration and dissolution actions of the anions. In these two cases, good deposits of chromium cannot be obtained. Empirically known facts on the effective anions in chromium plating can be thus explained in terms of the penetration and dissolution actions of the anions on the cathode.

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Conventional ion-plated films are not of high purity, but show an excellent adhesion, so that these films have been used as coating films of mechanical parts such as gears, ball bearings, etc. The ion-plating technique has been investigated in order to apply it to telecommunication switches and semiconductors, which require that the ion-plated films are of high purity and of proper adhesion. Sputter cleaning and redeposition have been investigated by changing ion bonbardment conditions. Surface condition should be indicated by cathodic current density during sputter cleaning. It reduces for a time and reaches to a constant value. Then the sputter cleaning is completed. Redeposition of sputtered atoms from substrates and holders is measured by Auger electron spectroscopic analysis. Contamination caused by redeposition is reduced rapidly by lowering Ar gas pressure. Optimum condition for ion-plating is determined, that is, Ar gas pressure is 3.6×10^-3 Torr and applied voltage is-4kV. Ag (99.9%) is deposited on polished Cu substrates by ion-plating and vacuum evaporation. The properties of ion-plated films are measured and compared with those of vacuum evaporated ones. Ion-plated films have smaller grain size, less columnar grains, pin holes, defects, and larger internal stress than vacuum evaporated ones. Therefore, the mechanical properties on ion-plated films should be superior to those of vacuum evaporated ones.

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The limiting current densities (i_lim) for the cation and anion exchange membranes in diluted nickel plating solutions were measured by using a small electrodialysis cell. In the flow velocity range of 0.3 to 3.1cm/sec, a linear relationship was obtained between i_lim and the flow velocity. In the nickel concentration range of 2.9 to 6.7g/l, the relationship between i_lim and the nickel concentration was also linear, which agreed with Nernst-Planck's equation. The relationship between i_lim and the temperature of the solution was best explained by using Arrhenius' equation. From the activation energy estimated by Arrhenius' equation, it was found that the change in i_lim is mainly due to the temperature dependence of diffusion coefficient. In the mixture of sulfuric acid and diluted nickel plating solution, a linear relationship exists between [H⁺]/[Ni²⁺] and i_lim of the cation exchange membrane, which agreed well with Rosenberg's equation.

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The mechanism for the occurrence of the burning of Al surface and the change of bath voltage during anodic oxidation were studied with a heat and mass transfer technique. The burning occurred at the point of the surface of the highest temperature rise before the start of the burning and at any point to which a concentrated oxalic acid solution from a small nozzle was injected. The analysis of the change in the bath voltage during anodizing and of the conductivity of the barrier layer showed that the concentration of oxalic acid near the barrier layer decreases with increasing thickness of the oxide film. The bath voltage calculated from a theoretical equation, derived from above analysis, agreed with the observed voltage. The experimental and theoretical considerations led to the following mechanism for the occurrence of the burning: At the final stage of anodizing before the burning, the concentration of the oxalic acid near the barrier layer becomes extremly low, and the formation of oxide film is controlled by the diffusion of oxalic acid through the porous layer. At this final stage, the anodizing current flows at the point of the AI surface of the highest temperature where the diffusion rate is maximum. This current concentration at that point causes the temperature rise, and this temperature rise promote the current concentration. The interactions of the temperature rise and the current concentrations finally lead to the burning.

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For the purpose of providing anodic coatings with abrasion resistance properties, micropore and cracks in the coatings were impregnated with liquid organic molybdenum compounds, more readily than with solid MoS₂. The amount of impregnated lubricants was greater in sulfuric-oxalic-citric acid coating than in sulfuric acid coating. This indicates that the amount increases with an increase in pore diameter rather than in pore number. Abrasion resistance due to the organic molybdenum compounds was not effected by frictional heat; however, a marked lubrication effect was observed by heating the anodic coatings at 200°C after impregnation. In the lubrication properties, the liquid molybdenum compounds were more effective than solid MoS₂ at low friction velocities less than 0.95 m/s, while, at high velocities exceeding 1.99m/s, MoS₂ was effective.

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Six kinds of inorganic, and nine kinds of organic lead compounds were studied as stabilizers against photodegradation of polyvinyl chloride (PVC). The molecular weight distribution (MWD) curves of outdoor exposed PVC containing various kinds of lead compounds were measured by using gel per meation chromatography (GPC). As a result MWD curves showed a good correlation between the average molecular weight and the change of surface appearance by outdoor exposition. Di-basic lead stearate and di-basic benzoate were found to be excellent stabilizers for PVC, both of which did not form any amount of gelled matter caused by the crosslinkage by photodegration. Generally, di-basic lead compounds showed a better stabilization of PVC than the normal lead compounds.

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