The elctroless plating of In-Sb alloy films on an alumina substrate was achieved with a bath using titanium trichloride as the reducing agent. The stoichiometric ratio of indium and antimony in deposits depended mainly on the concentration ratio of the antimony trichloride to the indium trichloride in the bath and on plating conditions, especially the pH.
Stoichiometric In-Sb films were produced from a solution containing 0.08M indium trichloride, 0.0002M antimony trichloride, 0.34M trisodium citrate, 0.14M trisodium nitrilotriacetate, 0.04M titanium trichloride, and sodium carbonate for pH control, under the conditions of pH 8.6, 7.8, and 7.2, corresponding to bath temperatures of 50°C, 60°C and 70°C. The resulting deposits were polycrystalline films of InSb (111), (220), and (311), which had Hall mobilities of 2.5∼4.2×10³cm²/V·s, which are nearly identical to those of InSb films which have been vacuumdeposited on an alumina substrate.

View full abstract

When sodium thiosulfate is added at a 2:1 ratio to the sodium sulfite system electrolyte, the silver dissolution current at peak printing is increased in the anodic polarization curve. At the same time, the current density in all potentials increased. In the cathodic polarization curves, the electrodeposition potential becomes lower when this reagent was added than for that in the pure sulfite system bath. The limiting current density is reduced due to the increase in polarization. In addition, the anodic reaction, mainly due to the complex action and increase in the concentration of sodium thiosulfate, reacts more actively with anodic oxidation dissolution, which results in destroying the passivated film, therefore making the silver surface appear to be a pure silver crystal surface.
Therefore, the changes in the concentration of silver ions, pH and the solution are reduced in the soidum thiosulfate system bath.

View full abstract

A photoacoustic technique was applied to study the phase changes in a W/O emulsion. The PA signal obtained for the emulsion was decreased as the rotation speed during emulsification was increased. The water phase was observed directly by cryo-SEM. The coalescence of the emulsion could be divided into three stages--induction, a faster period and an accelerated period--which were measured using the PA method and cryo-SEM.

View full abstract

We propose a method for evaluating the adhesive force of thin films. The back surface of a thin film is pressurized by gas through a small hole which penetrates its substrate. It is then peeled by a uniformly distributed load attributable to this gas pressure. The adhesive force of the thin film to its substrate is defined as the gas pressure, and peeling is detected with an acoustic emission (AE) sensor. The adhesion of diamond thin films deposited by filament-assisted CVD to a silicon substrate was measured using this method. The diamond thin film was peeled from the substrate without fracturing the film, and the measured adhesive forces were found to be independent of the film thickness. The AE signals caused by film peeling were distinguishable from those caused by a film fracture. These results confirm that this method can be used to measure the actual adhesive force without causing the thin film to fracture.

View full abstract

The body of an electrodeposited diamond wheel is usually made of carbon steel such as mild steel, and is not suited for use in a corrosive environment such as that involved in electrolytic grinding. A grinding wheel with a body made of stainless steel and electrodeposited in a sulfamate bath is widely used in dentistry as a grinding wheel. The grinding wheel used in industry undergoes a much larger grinding force compared to that in dental use, however. Thus, it would not necessarily appear suitable to manufacture an industrial grinding wheel using a manufacturing method similar to that used for a grinding wheel used in dental applications, for example.
The purpose of the present investigation is to develop a grinding wheel whose body is made of stainless steel SUS 304 and which is fit for use in industry. The effect of cutting point spacing was studied with grit distribution density on a wheel surface.
We found, as a result of the experiment, that pretreatment in electrodeposition on a stainless steel surface is very important and that an effective stainless steel wheel for industrial use can be obtained through a process that ensurs sufficient pretreatment. Furthermore, the grit distribution density could be varied by varying the grit sprinkling time, which clarified the effect of the grit density.

View full abstract

Boron ions were implanted in Ti-C-N coatings by using a multienergy technique, and the effect of the implantation on the crystal structures and microhardness of the Ti-C-N coatings were studied. A SIMS analysis showed a uniform concentration of boron atoms in the coatings at depths from 0.05μm to 0.33μm due to the multienergy implantation, which was in good agreement with calculated results. As the boron concentration is increased, the lattice parameter of Ti-C-N increases in value and the broadening of the X-ray diffraction peak becomes observable. This suggests that Ti-C-N is amorphized. The formation of borides such as TiB₂ and BN was not found. It was assumed that boron atoms were implanted interstitially in the lattice and partially expanded interplanar spacing. Internal stresses caused by the foreign boron atoms in the Ti-C-N lattice could induce the lattice to become rearranged. The microhardness of the Ti-C-N coatings was decreased by this implantation of boron atoms.

View full abstract