Tetsuo Nakai

Ion‐beam plating using mass‐analyzed ions

An ion‐beam‐plating apparatus controlled by mass spectrometry was developed to study the fundamentals of ion plating. A decelerating lens system was fitted to the apparatus and the deposition was carried out at ion energies from 30 to 300 eV. By the elimination of contaminant ions and neutrals and making the kinetic energy of incident ion‐beam constant the fundamental deposition mechanism can be discussed. A high‐voltage transmission electron microscope at 2000 kV was employed for examining ion‐beam‐induced dislocations in single‐crystal substrates of aluminum and the growth of ion‐beam‐plated films. The effects of kinetic energy and substrate orientation are discussed. It was found that the higher the ion energy, the higher the dislocation density. A high density of dislocation was observed on the close‐packed plane, i.e., (111) of an aluminum single crystal. Stainless steel was also used as a substrate. In this case, a twin deformation was found. The high‐voltage transmission electron microscope provide...

Prevention of fretting by ion plated film

Abstract A new technological application of the ion plating technique to the prevention of fretting has been studied. Ion plating was done using gold and silver, which are commonly employed as thin metal film lubricants and also boron carbide which has extremely good wear resistance. The anti-fretting property of the ion plated film was always superior to that of the sputtered or vacuum evaporated film. The ion plated boron carbide film showed the best resistance to fretting. The better adhesion of ion plated films was responsible for the better anti-wear property. Transmission electron microscopy was used to study ion plated films.

Influence of the N*(1470) to Density Isomer and a Phase Transition of the Baryon-Antibaryon Plasma at Finite Temperatures

In this letter we discuss two subjects for the density isomer at finite temperature. The first subject is the influence of the N*(470) resonance, and the second is a phase transition of the baryon· antibaryon plasma. The density isomerism was recently studied by Bogutai) using a relativistic mean field theory consistent with the known bulk properties of the ground state of the nuclear matter (saturation energy and density and compressibility). In the model, nucleon (cjJ) and delta isobar (cjJ).) interact with neutral scalar (</J) and vector (V) meson fields by the following Lagrangian:

On the Application of Ion Plating Technique to Tribology

A new method of ion plating is described in which the high voltage DC sputtering is applied. The micro-structures of ion plated silver, gold and boron carbide films were observed under a transmission electron microscope, and it revealed that they are quite different from those of vacuum evaporation and of sputtering. This may be caused from the fact that the high kinetic energy of the target material would form very strong bonded film in the case of ion plating. As it can be expected well that the ion plating technique could be applied to the field of high-precision technology, the toughness or the durability of films becomes of much importance. Therefore, further discussions are made from the results of evaluating the anti-friction and anti-wear properties of ion plated films, and from the SEM observations of surfaces.

Pion Condensation and Density Isomer in a Relativistic Mean Field Theory

The coexistence of two exotic states, the pion condensate and the density isomer, is discussed based on a relativistic mean field theory. Our model is constructed so as to account for the known bulk properties of the ground state of the nuclear matter (saturation energy and density and compressibility). The development of these exotic states is quite sensitive to the pion-nucleon coupling constant and the coupling between the delta and the scalar meson. We extend the studies of Banerjee et a1. to include the delta resonances and the nucleon-delta coupling through the pion. It becomes evident that the occurrence of two exotic states is related to the effective nucleon mass in a reverse way. We may conclude that for zero temperature the coexistent state does not exist and at higher densities the density isomer branch has lowest energies.

Application of Ion Plating Technique to Technology

Ion plated film has good properties, that is, a good adherence onto the substrate, a high strength of the film and a film formation all over the surface without rotation or inclination of the substrate, because ion plating is the new technique by which ions are deposited onto the substrate under the electric field in vacuum. So, it is easily imagined that ion plating technique can be applied to technology at wide region, e.g. application to tribology and strengthening of the materials. In the present research, an ion plating apparatus with the sputtering technique, which can be applied to refractory materials and chemical compounds, was developed, and tensile tests of the advanced filaments covered with B4C, Cu, and Ti films were performed with an Instoron tensile testing machine. The results of the tensile tests reveal that the proportional limit and tensile strength of the stainless steel covered with B4C increased up to about 133 % and 126% respectively. Also discussions were made about disruption of advanced filaments with a SEM.