Steel sheet coated with a self-lubricating resin consisting of polyvinylbutyral resin with added polyolefin wax was found to have excellent press formability. The self-lubricating property is affected by the degree of cross-linking in the base resin which forms the film and is obtained by baking in the range of 120∼180°C. The effect of the properties of the base resin on press formability was therefore studied using polyvinyl butyral resin. The maximum drawing height of the specimens increased when the specimen temperature during press forming was near the glass transition temperature Tg of the base resin. This was attributed to the fact that the coefficient of friction μ of the base resin reached its minimum value near Tg because the decreaing tensile strength and increasing elongation of the resin at this temperature permitted easier deformation.
Formation of yttrium oxide by electrodeposition was studied in DMF containing YCl3 and a small amount of water, and rectangular pulse electrodeposition technique was applied. Y2O3 was formed during the electrodeposition, and Y2O3:Eu (III) film was formed also in DMF containing YCl3, EuCl3 and a small amount of water. The deposited film was analyzed by atomic absorption spectroscopy, X-ray diffraction, EPMA, XPS and SEM. The deposited Y2O3:Eu (III) film showed photoluminescence and cathode luminescence (red-orange color).
The effect of plasma and arc sprayed Al coatings on the vaporization and combustion of kerosene was investigated by means of surface roughness observation, measurement of vaporization speed and weight gain determination of fuel deposits on a kerosene burner. A kerosene burner with sprayed Al coatings showed better performance in vaporization of kerosene and combustion stability than one without Al coatings, because of the surface roughness and high porosity of the coating layer. A marked decrease in fuel deposits on the burner was observed at arc sprayed Al coatings after combustion of partially oxidized kerosene for 1h.
Plasma-carburizing using the glow discharge of hydrocarbon gases produces a high concentration of carbon in the surface layer within a short period of time. It has thus been frequently applied industrially to ferrous materials to concentrate carbon content in the case region or to produce a greater case depth. The authors have conducted a series of studies on the plasma-carburizing of transition metals belonging to groups IVa∼VIa, such as titanium and tungsten. In this study, Ti-6Al-4V alloy was plasma-carburized to investigate the process of formation of titanium carbides and their mechanical properties after treatment. The following results were obtained. 1) A fine carbide layer consisting of TiC and having a hardness of Hv 2140 was formed in the surface and a carbon diffusion layer was formed beneath this carbide layer. 2) The rate of growth of the carbide layer was proportional to the 1/2th power of treatment time. 3) In cases where an amorphous carbon layer was formed on the surface, the growth of carbide layer was markedly slowed down.
Room temperature softening of copper film electrodeposited from ethylenediamine complex baths was investigated along with its mechanism. The bright copper film electrodeposited from baths containing a small quantity of thiodiglycollic acid were of small crystallite size and contained small amounts of impurities. The films obtained were found to increase in crystallite size, decrease in microhardness and undergo orientation transformations into closed packed facet of the fcc lattice, resulting in a first recrystallization at room temperature.
Co-B alloy films having various B contents were electroless-deposited and heat-treated at 400°C for 1h. X-ray diffraction measurement indicated the formation of crystalline Co or Co-B as a result of the heat-treatment. Cathodic polarization curves of these films were measured and hydrogen evolution on them and electrocatalysis of them to hydrogen evolution were investigated by the Tafel slopes and exchange current densities derived from the curves.