[en] Statistical design-of-experiment studies of the thermal spraying of polymer powders are presented. Studies of the subsonic combustion (i.e., Flame) process were conducted in order to determine the quality and economics of polyester and urethane coatings. Thermally sprayed polymer coatings are of interest to several industries for anticorrosion applications, including the chemical, automotive, and aircraft industries. In this study, the coating design has been optimized for a site-specific application using Taguchi-type fractional-factorial experiments. Optimized coating designs are presented for the two powder systems. A substantial range of thermal processing conditions and their effect on the resultant polymer coatings is presented. The coatings were characterized by optical metallography, hardness testing, tensile testing, and compositional analysis. Characterization of the coatings yielded the thickness, bond strength, Knoop microhardness, roughness, deposition efficiency, and porosity. Confirmation testing was accomplished to verify the coating designs

[en] Table top short pulse Peta-watt laser system is the most promising light source to drive studying high energy field physics in advance photon research. To achieve high efficiency laser oscillation in stable condition, it is required to pull out the best performance from laser crystals as the gain medium. Therefore, we have conducted cooperative investigation with Mitsui Mining and Smelting Co., LTD. to create large ideal laser crystals by improved growth methods which solve several problems in usual growth techniques. This report describes specifications, results of operation, and improvements in two different types of growth furnaces which make homogeneous doped concentration along growth direction of Nd:YAG laser crystal and large fluoride laser crystals with a wide band gap, respectively. It also describes the first four results of crystals such as YAG, Nd:YAG, YLF, and LBO grown by these furnaces. (author)

No abstract available

[en] C/C composites are one of the representative advanced composites, since they have superior mechanical properties (strength-to-weight ratio, relative Young high modulus and heat resistance). Many researchers have pointed out so far that their mechanical properties depend on the degree of graphitization for their components (matrices and fibers) and their precise evaluation techniques are required from the view point of practicality. Therefore, we investigated the correlation between the degree of graphitization measured by X-ray Diffraction Analysis (XRD) and the redox behavior of surface oxides measured by Potential Step Chronoamperometry (PSCA). As specimens, three kinds of C/Cs composed of the same matrices (pitch type) and different fibers (mesophase pitch type) were used basically. In addition, only fibers of each specimen were graphitized at 2773K in advance and also used as specimens to investigate the effect of fiber indicate that the specimens of pre-treated fibers developed the graphite structure and have high degree of graphitization, since their integrated intensity is higher and their half-value width is smaller than those of non-treated specimens. The results of PSCA at 0.4V indicate that the quantity of electricity for the formation of phenol-type oxides on the surface decreased with increasing degree of graphitization. On the other hand, PSCA at 0.6-0.8V indicates that the quantity of electricity for the formation of carbonyl-type oxides had no correlation with the degree of graphitization. However, PSCA on the reduction side (from 0.8V to 0.4V and from 0.8V to 0.6V) indicates that the quantity increased with the degree of graphitization. (author)

[en] The properties of short fibre reinforced metal matrix composites can be enhanced by controlling the directionality of the fibers. In the reported research, the multiple live feed injection moulding technique was successfully used for controlling the orientation of short fibers in powder injection molded metal matrix composites. A range of heavily loaded short fibre reinforced metal matrix compounds were injection molded by both parameters. The level of fibre orientation achieved in injection molded components was assessed by calculation of the orientation factor. One result of this investigation was identification of the moulding composition to achieve the highest level of fibre orientation in a preferred direction. (author)

[en] In situ ESR-spectroscopic investigations of the electrochemical growth of polypyrrole (PPy) in 0.1 mol dm^-3 toluene sulfonic acid solution in acetonitrile are presented. The films were deposited potentiostatically and galvanostatically onto gold electrodes. ESR spectra were simultaneously recorded during electrodeposition processes at high and low current densities, respectively. Differences in the paramagnetic properties of the PPy films thus prepared have been observed depending on the applied current densities. Furthermore, the spin concentration in the PPy film is not proportional to the injected charge. Therefore, two different mechanisms of film formation occur depending on the applied current densities. ((orig.))

[en] Hydrothermal growth of single crystals of PbSO₄, which is known as a natural mineral called anglesite, was investigated. Lead nitrate and nitric acid solutions were found to be useful for the growth of angle-site on the basis of the experimental results on the dissolution behavior. Relatively large euhedral single crystals bound by {210} and {101} planes were successfully grown in 1.5 mol/kg Pb(NO₃)₂ at 400degC and 100 MPa. Optical characterization revealed that the grown anglesite crystals can be useful for scintillators material. (author)

[en] The method of obtaining of trioxide of rare earth metals used as hydrogen absorber for hydrogen energetics was elaborated. The method includes annealing of trihydroxide of rare earth metals R(OH)₃ in vacuum at temperature 140 - 150 C during 16 - 24 h. (author)

[en] The effect of mechanical milling on fullerene and metal-0.3 mol% fullerene (M-fullerene), where M=Al,Fe,Ni,Cu or Zn has been studied. Fullerene was produced by evaporating graphite electrodes in He atmosphere. The synthesized fullerene contained a mixture of C₆₀ (87 vol.%) and C₇₀ (13 vol.%). For comparison milling experiments on M-15.7 at.%C has been carried out. X-ray diffraction studies of fullerene milled for 720ks showed that fullerene is stable. However, liquid chromatography measurements showed that the fraction of C₆₀ reduces and a dimer of it, probably C₁₂₀ grows with milling time, whereas the fraction of C₇₀ remains the same. Milling of fullerene with metal indicates that fullerene retains its identity in Al- and Zn-fullerene systems whereas the molecular structure of fullerene is not maintained when the metal is Cu, Fe or Ni. Transmission electron microscopic study has shown that in the case of MA powders of Al- and Fe-fullerene the diffraction rings corresponding to fullerene, graphite or carbides are not visible and MA powders were stable under electron beam. While, in the case of MA powders of Cu- or Ni-fullerene systems, graphite form under electron beam and metals in MA powders become spherical which is associated with the evaporation of metal particles. The sintered compacts made from MA powder of metal-fullerene and metal-graphite showed similar hardness. In carbide forming systems formation of carbides (Al₄C₃, Fe₃C) were observed in the sintered compacts. (orig.)

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