Ba₂NaNb₅₁₅ (BNN) thin films were formed on sapphire (012) substrates by electron cyclotron resonance plasma sputtering by using ring shaped targets. BNN thin films of single phase were obtained at the substrate temperature in the range between 773 and 923 K by using the target composition of Ba : Na : Nb = 1.2: 1.2 : 5.0. The (001) oriented BNN films were successfully obtained at 773 and 923 K. The contents of Ba, Na and Nb in the films were independent of substrate temperature in the range between 773 and 923 K. Deposition rates of the BNN thin films were estimated to be about 8.3×10^-2 nm/s. The absorption edge of the BNN films became clear in the vicinity of 300 nm. The transmittance in the wavelength between 400 and 2500 nm have exceedingly by more than 80 %. The refractive indices of the films were estimated between 1.7 and 3.0. The dielectric constants of the BNN films were about 10.

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Particle shape classification technique of P/M powders is introduced for high-grade powder preparation, which leads to the stabilization of P/M processing and the high quality of P/M products. The vibrating inclined plate method was used for the shape classification. In the particle shape separator, powder particles rolled down on an inclined plate vibrated by an electromagnetic vibrator. The morphological characteristics of both powders before and after testing were examined with the particle size-shape dispersion diagrams in order to investigate the influences of the operating conditions on the shape classification. Moreover, a simulation of this shape classification was attempted according to the kinetics of collision between ellipsoidalparticles and an inclined plate.

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The filled skutterudite compounds, M_yFe_xCo_4-xSb₁₂ (x=0-1.0, y=0-0.15, M=Ce, La, Y), were prepared by a new solid state reaction method using Co, Fe, Sb, CeCl₃.6H₂O, LaCl₃.6H₂O and YCl₃.6H₂O powders, and their thermoelectric properties were investigated. M_yFe_xCo_4-xSb₁₂ (x=0-1.0, y=0-0.15, M=Ce, La, Y) compounds showed p-type conduction. The electrical conductiviy (σ) increased with increasing Fe content. The Seebeck coefficient (α) increased with increasing Fe content for MFe_xCo_4-xSb₁₂, but decreased with increasing Fe content for Fe_xCo_4-x, Sb₁₂. The Lattice thermal conductivity (KL) decreased significantly with the substitution of Fe for Co and the filling of M (M=Ce, La, Y) into the Sb icosahedral voids, while the carrier thermal conductivity (Kcar) was not much affected by the Fe substitution and the M (Ce, La, Y) filling. The thermoelectric figure of merit was improved by the combinatior of Fe substitution and M (Ce, La, Y) filling.

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Metal injection molding (MIM) process is hoped to be an advanced powder processing technique for near net shape forming the high density and more complicated parts. However, there still remains the issue of limitation in the shape and volume of injection molded compacts because of the use of die. Application of joining technique may be one of approaches to improve the above problems in MIM process.
In this study, in order to develop a new joining MIM process for more functional and complicated parts, the exuded wax from green compacts during solvent debinding was applied to join the couples of same or different materials such as iron, stainless steels (SUS304L, 4301, 630) and WC-5Co-20, 35Fe compacts. This paper describes mainly the influence of the solvent debinding temperature and combination of joining materials on the joining process, and also describes the shear strength and microstructures of the joined parts.

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In turning of alloy steels, the tool wear generally increases with the increase of the cutting speed. In order to find out the effective tool materials for the high speed turning of the alloy steels, SCr420 was turned with the coated cemented carbide tools and ceramics tools. The tool wear was experimentally investigated at the cutting speed from 5.0m/s to 20.0m/s, the feed rate 0.05mm/rev and the depth of cut 0.1mm. Furthermore, the influence of the chamfer honed edge width and angle of the Al₂O₃ ceramics tool on the tool wear was also investigated. The main results obtained are as follows: (1) The Al₂O₃ ceramics tool showed the slowest wear progress at the cutting speed 20.0m/s. (2) The tool wear progress at the chamfer honed edge angle 25°became slow with the decrease of the chamfer honed edge width at the cutting speed 20.0m/s. (3) The cutting force decreased with the decrease of the chamfer honed edge width.

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Elemental cobalt and titanium powder mixtures have been mechanically alloyed (MA) to form two independent Co-Ti intermetallic compositions. In both cases nanometre-sized-crystalline particles have been embedded into an amorphous matrix. Resulting powders have been found to consist of Co_66.4Fe_0.6Ti₃₃and Co_48.6Fe_1.0Ti_50.4. At these concentrations and independent of the Fe content, formation of hexagonal Co₂Ti intermetallic has been observed when heating the powders up to 873 and 1173K, respectively. Crystallization of powders also has resulted in the formation of Co₃Ti and CoTi compounds, which respectively co-exist with the Co, Ti phase.

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Nd-Fe-B amorphous alloy powders produced by rapid solidification processing were mechanically ground in an argon atmosphere. The resultant powders and those annealed powders were examined by X-ray diffraction, differential scanning calorimetry, and vibrating sample magnetometer. The crystallization temperature of Nd-Fe-B amorphous alloy powders decreased as the milling time increased. It was found that the crystallization of a-iron from amorphous matrix took place in the extended milling. Heat treatment of the resultant powders resulted in the formation of Nd2Fe14B ferromagnetic phase regardless of the milling time. The resultant Nd-Fe-B powders had a slightly high remanence value compared to those obtained from the original melt-spun counterparts.

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Density distribution in green pellets of many kinds of Al₂O₃ powders was evaluated by energy dispersive X-ray analysis and calculations using a finite element method. Calculated density distributions agreed well with experimental results. Density homogeneity in green pellet has a distinct correlation with a material constant, n, defined in the following yield function.
ρ²ⁿB²=((σ₁, -σ₂)²+(σ₂-σ₃)²+(σ₃-σ₁)²)/2+A²(l-ρ)^2mσ²_m
where ρ is relative green density, σ_i is normal stress, σ_m is mean normal stress and B, A, in are material constants.

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Gels with nominal molar compositions of CaO⋅MgO⋅2SiO₂ and CaO⋅MgO⋅1.95SiO₂ using a mixture of each individual metal alkoxide were prepared without adding hydrochloric acid as a catalyst. The crystallization of CaMgSi₂O₆ (diopside) by heating the gels at various temperatures was investigated. Elemental analysis by EPMA showed the microscopic compositional nonuniformity of the metals in the gels. It was found from DTA-TG, XRD and FTIR analyses that calcium silicates firstly crystallized from a gel-like glass upon heating at temperatures below 1073K, beyond which CaMgSi₂O₆ formed as a predominant crystalline phase. This crystallization process was different from that observed for calcined powders of carbonate and oxides prepared by the conventional solid-state reaction method.

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Graphite-Ni composites were fabricated by hot pressing from graphite powder electrolessplated with Ni and chopped carbon fiber as the raw materials. The relationship of chopped carbon fiber volume fraction (Vf) and Ni matrix volume fraction (VNi) on mechanical characteristics, friction and wear were reviewed. The results were as followed:
(1) Bending strength and Young's modulus increase with Vf at constant porosity. In case that porosity increases, these decrease with porosity.
(2) Friction coefficients of these composites increase with an increase of Vf with VNi more than 40 percents.
(3) Specific wear amount of these composites decrease by a chopped carbon fiber addition, and the decrease quantity is influenced by Vf, VNi.

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A thin-film thermistor using (Al, Cr, Fe)₂O₃ film with corundum structure was prepared, and characteristics of resistance-temperature and responsiveness were investigated. The corundum-type (Al, Cr, Fe)₂O₃ film was obtained by plasma enhanced metal organic chemical vapor deposition (MOCVD)and heat treatment in air. In this process, the deposition rate of the film was as high as 40 nm/min and the crystallization temperature for corundum structure was as low as 1200°C. The characteristics of resistance-temperature and responsiveness indicated that the thin-film thermistor allows temperature detection over wide range from 200°C to 950°C and rapid responsiveness of 3 times as fast as that of a conventional bulk thermistor.

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We have investigated the influence on the superconductivity of the iodine intercalation into sintered samples of Bi2212 and Bi2223 superconductors by using I₂ or FeI₂ as reactant. It has been found from X-ray diffraction that iodine intercalated compound of IXBi₂Sr₂Ca₂Cu₃Oy was prepared by intercalation by using FeI2. The iodine intercalation using FeI₂ as a reactant into Bi2223 phase is reported for the first time as long as we know.
The decrease of T_Conset, ΔT_Con, for Bi2223 was smaller than one for Bi2212. This is likely due to the number of the CuO₂ planes between BiO planes. In the case using FeI₂, I₂ originates from FeI₂ with reduction of host.

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We have investigated the influence on the superconductivity of X for I_xBi₂Sr₂Ca_(n-1)Cu_nO_y (n=2, 3) prepared by intercalation into Bi2212 single crystal, Bi2212 and Bi2223 polycrystalline superconductors by using FeI₂ as reactant. The coexistence of Bi2212 phase and stage-1 intercalated phase is found in the range 0.2≤X≤0.9 by using XRD of single crystal samples. The sharp slope, dT_c/dX, is also found for X≥0.9 from the measurement of the resistivity of I_xBi₂Sr₂CaCu₂O_y single crystal samples. The slope of I_xBi₂Sr₂CaCu₂O_y polycrystalline samples is different from ones of single crystal samples and I_xBi₂Sr₂Ca₂Cu₂O_y polycrystalline samples.

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The effects of lithium doping by solid state reaction on the electrochemical intercalation into the Bi-2212 phase with lihium were investigated through the structure and superconducting properties. The expansion rates of lattice parameters with respect to the amount of lithium intercalated by electrochemical reaction decreased with increasing the amount of lithium doped by solid state reaction. The change of superconducting critical temperature with respect to average valence of copper became small with increasing the amount of lithium doped by solid state reaction. The electrochemical reaction removed lithium from Bi-2212 phase as much as the amount of lithium intercalated by electrochemical reaction. The result supports the possibility that lithium doped by solid state reaction and electrochemical reaction occupies the different sites in the Bi-2212 phase.

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Bi-2223 bulk superconductors were irradiated with 290MeV/n ⁴⁰Ar¹⁸⁺ ions. ⁴⁰Ar¹⁸⁺ irradiation effects on flux pinning of Bi-2223, which were estimated as ΔM from magnetic hysterisis loops measured by SQUID and VSM, were discussed. Irradiated samples had enlarged magnetic hysterisis loops than unirradiated samples. Moreover, the increment of AM depended on depth from the irradiation surface. Microstructure of irradiated samples were observed by high-resolution transmission electron microscopy (HR-TEM). However, irradiation defects such as the columnar defects were not observed in these samples.

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The Raman spectra of (Pb₂Cu)Sr₂Y_1-xCa_xCu₂O_8+δ (Pb3212), (Pb₂Cu)Sr_0.9La_1.1CuO_6+δ (Pb3201), and (Pb_0.5Cu_0.5)Sr₂YCu₂O_7+δ (Pb1212) were studied and vibrational assignments in harmony with the layer stacking sequencies found in these Pb-based high-Tc superconducting oxides were proposed. In particular, the assignment of the 480-and 580-cm^-1 Raman bands to oxygen in the PbO and SrO layers, respectively, was unambiguously established. In the case of Pb3212 we found that the intensities of modes connected to the CuO₂-plane vibrations decreased with increasing carrier concentration. This effect was attributed to the increased metallic screening in the CuO₂ planes that can be expected in the hole-rich Ca-doped samples.

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Raman spectra of Sr_14-xCa_xCu₂₄O₄₁ in single-crystal and polycrystalline samples were investigated. At first, from the polarization and a comparison with previous reports on isostructural compounds, we identify the (4A_g+4B_1g+3B_2g+B_3g) modes that are Raman active within the simple Fmmm structure. Second, it is clear that hole carriers transfer from chain to ladder with substituting Sr for Ca in Sr₁₄Cu₂₄O₄₁, because on the one hand the intensity for modes associated with oxygen vibrations for chain increases and on the other hand the one associated with ladder decreases with Ca content x increasing. Third, we observe new additional modes at low temperature in this system. Especially, for both Sr₁₄Cu₂₄O₄₁ and Sr_7.2Ca_6.8Cu₂₄O₄₁, the temperature, at which the new mode near 500 cm-1 shows up, is nearly identical to the temperature, at which the electrical and magnetic anomalies have been observed. This result is consistent with the picture that holes in the ladder are paired and localized below the temperature.

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First, we have studied the stability of Sr_2-xBa_xCu₃O₄Cl_2-yBr_y of the 2342 phase with the Cu₃O₄ plane, which is composed of the Cu(1)O₂ and extra Cu(2) sublattices, in the temperature range between 600 and 950°C. It has been found that a mixture of (Sr, Ba)₂CuO₂(Cl, Br)₂ With the CuO₂ plane and CuO becomes stable instead of the 2342 phase with the Cu₃O₄ plane for smaller values of x and y at low temperatures. Next, the electrical and magnetic properties of Sr_2-xBa_xCu₃O₄Cl_2-yBr_y with the Cu₃O₄ plane have been investigated. The electrical resistivity exhibits semiconductive behavior. The magnetic susceptibility shows three-dimensional antiferromagnetic order below T_N(1)=300-400K and T_N(2)-30K for the Cu(1) and Cu(2) sublattices, respectively. A broad peak due to the two-dimensional antiferromagnetic order in the Cu(2) sublattice is also observed around T_N^2D(2)=100K. With increasing x and y, the lattice parameters increase, the electrical resistivity increases and values of both T_N(1) and T_N ^2D(2) decrease. These results are explained as being due to the decrease of the overlaps between Cu3d and O2p, COP, Br4p orbits.

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Magnetic properties of the high pressure (HP) phase (VO)₂P₂O₂ was studied. It has an unique kind of spin-1/2 Heisenberg alternating antiferromagnetic(AF) chain, whereas its ambient pressure (AP) phase comprises two crystallographically different chains. Magnetic susceptibility, high-field magnetization and heat capacity of the HP phase were measured, and existance of a single spin gap was confirmed. In addition, differential thermal analysis under high pressure was performed to probe the melting point of this HP phase, and its single crystal was grown. Powder XRD under high pressure revealed that there exist more other HP phases.

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