Wear behavior of silicon nitride (Si₃N₄) ceramic tools in turning gray cast iron was evaluated. Wear of the flank and rake faces decreased with increasing cutting speed in a range of 100 to 300m/min. Deposits on the rake and flank faces after cutting 3.3km were analyzed by electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). When the cutting speed was 300m/min, surface deposits consisting of Mn, S, Al, and O were detected by EPMA. In contrast, little Al and O were found on the tool surface at a cutting speed of 100m/min. Similar results were obtained for the flank face by EPMA. The rake face of the tool after cutting at 300m/min was analyzed in detail by XPS. It was determined that the main contents of the surface deposits were Al₂O₃ and silicon oxide (SiO₂ and SiO_x); the layer was 1 to 2μm in thickness. It was revealed that the oxide deposits prevented direct contact between silicon nitride cutting tool and the workpiece. This worked to improve tool life when turning of gray cast iron at a high cutting speed.

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Ultra-precision processing technique is indispensable for the production of high-quality tip to a desired shape from a LaB₆ single crystal chip which recently emerged as a cathode material for electron guns. This report describes a high-precision, high-quality tip processing method of LaB₆, and evaluates the electron emission characteristics of various electron guns manufactured for this experiment. A new polishing method was designed implementing a taper processing method, and applied to the finishing process with the combination of a hard plastic disk polisher and slurry in which ultra-fine particles are suspended. As a result, this new polishing method was proved to produce a strain-free mirror surface tip as small as 2μm radius. Desired tip radius was also obtained applying the elastic polisher. Several tips of LaB₆ crystals have been processed accordingly using new method to an apical angle of θ=90° at the radius of curvature (R) of 10, 100μm and ∞ (flat tip) each, and incorporated into the Vogel-type electron guns in order to understand various electron characteristics. This experiment confirmed that the smaller R is, the higher the brightness becomes, and the larger R is, the spot-shape becomes larger.

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The structural change of the (100-x) (0.6Li₂S⋅0.4SiS₂)⋅xLi₃PO₄ oxysulfide glasses during crystallization was analyzed by means of solid-state nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS). The unique tetrahedral units of SiO_nS_4-n (n=1, 2, 3) and PO_nS_4-n (n=1, 2, 3) present in the glass samples vanished and the SiS₄, SiO₄, PS₄ and PO₄ units increased with proceeding of the crystallization process. Nonbridging sulfur and oxygen atoms decreased while bridging oxygens and S^2- increased with proceeding of the crystallization process. Large structural difference between the glass and the corresponding crystallized sample explained the high stability against crystallization found in the oxysulfide glass with the composition of x=5.

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Qualitative and quantitative thermal behavior of carbonate ions incorporated into hydroxyapatite with various Sr-Ca compositions was investigated. Desorption of CO₂ from apatite by heating and the amount of CO₂ that evolved from the apatite were strongly influenced by the Sr content. Sr-60%-substituted apatite (designated as Sr60) showed the lowest peak temperature and the most desorbed amount of CO₂ of all the samples Sr0, Sr20, Sr40, Sr60, Sr80 and Sr100. The dependence of the peak temperature on Sr content was similar to that of the thermal stability of the apatite on Sr content, suggesting that the apatite with lower thermal stability was able to incorporate more carbonate ions into its structure.

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DR1 (4-[N-ethyl-N-(2-hydroxyethyl)]amino-4′-nitro-azobenzene) doped silica films were prepared by a solgel method, from a solution of tetraethyl orthosilicate and DR1. The films were optically poled and heat-treated to build a polarized structure for second-order optical nonlinearity. Two seed beams at 1064 and 532nm wavelengths from a Q-switched Nd: YAG laser were coaxially applied to the films. Second-harmonic generation was observed from the films after the optical-poling. We found that the rigid silica matrix prevented the relaxation of polarized structure.

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PbBi₄Zr_xTi_4-xO₁₅ (PBZT) ceramics were synthesized for the first time from sol-gel derived powders, and their electrical properties were investigated. The orthorhombic PbBi₄Ti₄O₁₅ (PBT) structure was maintained in the Zr concentration (x) range up to x=2.0. However, in the range of 0<x≤0.5, monotonous changes in the lattice parameters were observed as well as the absence of a second phase. PBZT powders and ceramics were prepared by using both a conventional powder-mixing process and a sol-gel technique. The conventional powder-mixing process did not lead to PBZT phase formation under any conditions, even with x=0.5. The substitution of titanium by zirconium increased the Curie temperature (T_C) from 554 to 563°C and decreased the relative permittivity at T_C from 3003 to 1329 at x=1.0. A remarkable increase in ferroelectric properties was observed at a Zr concentration of x=0.5. 2P_r and 2E_c values at x=0.5 were 2.4μC/cm² and 18.4kV/cm, respectively, at room temperature, and 9.9μC/cm² and 28.1kV/cm, respectively, at 120°C, at an electric field of 40kV/cm.

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The sol-gel method was applied to the preparation of Fe-zircon pigments. Following results were obtained.
(1) Fe-zircon pigment was successfully prepared by heat treating the gel made from Si(OC₂H₅)₄, ZrOCl⋅8H₂O and FeCl₃⋅6H₂O at 900-1000°C and by adding LiCl as a mineralizer. The preparation temperature was lower than that in the conventional solid-state method, and the pigment powders were obtained by simple process, namely without using complicated mixture of several mineralizers.
(2) The red color value and chemical durability of the pigments were improved, compared to the commercial pigment.
(3) The oxidation state of large part of Fe ions in the pigments was trivalent, and Fe³⁺ ions were considered to exist as minute α-Fe₂O₃ particles which are uniformly embedded in the zircon matrix.

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The Stoichiometric compound MgCr₂O₄ was sintered at various holding times from 10min to 100h. All samples had a single-phase spinel structure and were p-type semiconductors. The lattice constants increased with increasing the holding time in sintering. The electrical resistivity and the Seebeck coefficient decreased with increasing holding time. These phenomena indicate an increase in the electron carrier density. The activation energies of conduction and Seebeck coefficients differed by 0.3eV. This suggests that the conduction mechanism of this system is based not on band-type conduction, but on heat-activated p-type semiconductor conduction by electron holes introduced by Cr vacancies.

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Polycrystalline samples of ScRh₃B_x, which consists of reactive Sc and high melting point Rh and B elements, have been successfully synthesized by the arc melting method. ScRh₃B_x has the perovskite cubic structure (space group Pm3m). Perovskite-type ScRh₃B_x exists in the range of 0≤x≤1.000 (0 to 20mol%B). ScRh₃ has the AuCu₃ type structure (space group Pm3m). The lattice parameter a in annealed ScRh₃B_x depends on x, and varies linearly from a=0.3903(1)nm (x=0) to 0.40799(3)nm (x=1.000). The micro-Vickers hardness of the annealed ScRh₃B_x increases with increasing B content in the range x=0-1.000, from 1.9(±0.1)GPa for ScRh₃ (0mol%B) to 9.9(±0.1)GPa for ScRh₃B_1.000 (20mol%B). TG analysis indicates that the onset temperature of oxidation for ScRh₃B_1.000 is 595°C. The sharp exothermic peak of the DTA curve is found at 797°C. Weight gain of the sample by heating in air up to 1200°C is 12.7%. The sample changed to Rh plus Sc₂O₃ and ScBO₃ after oxidation. The weight gain of the sample decreases with decreasing boron content.

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The extraordinarily large expansion observed during sintering of bodies from incinerated ash of sewage sludge was investigated in connection with chemical states of iron in the bodies. The ash was pressed into a rectangular body under 100MPa, and the body was fired at 1000°C for 3h in flowing Ar-O₂(P_O2: 0.1-1.0kPa) atmosphere. The bulk density of the bodies fired in various atmospheres decreased with a decrease in oxygen partial pressure. The formation of porous black core accompanied by extraordinary expansion was observed in the bodies fired at P_O2=0.1-0.7kPa. Reflectance spectra and the ratio of Fe²⁺ to total Fe measured by chemical analysis indicated that iron oxide in the black core was in the form of FeO or Fe₃O₄. The evolution rate of CO₂ during heating of the body was measured by using a quadruple mass spectrometer. In the case of P_O2=0.5kPa, the evolution rate of CO₂ at 1000°C was higher than the rate of O₂ supply through the atmospheric gas flow. The fact indicated that the ferric oxide was reduced to ferrous oxide by the residual carbon and the evolution of CO₂ occurred inside the body under lower oxygen partial pressure.

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Synthesis and densification of celsian was investigated. The mixture which was measured to be the stoichiometric ratio of celsian was melted by using arc melting technique to synthesize the material in glass state. Milled powder of the glass was mold pressed and CIPed to obtain green compacts. Dense celsian ceramics composed of monoclinic crystalline phase could be obtained by heat-treating the compact at 1500°C for 4h in air. Enhanced densification of the present material was ascribed to the viscous deformation of the glass phase. Existence of zirconia, which was dissolved into the glass from refractory bricks during arc melting, was considered to promote the crystallization of monoclinic phase of celsian which was required to exhibit low thermal expansion behavior. Fracture strength and the Young's modulus of the resultant celsian were 148MPa and 138GPa at room temperature, respectively. Thermal expansion coefficient of the sample was 4.0×10^-6/°C between room temperature and 1000°C.

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Carbonation reaction of low-heat cement was investigated in order to develop practical applications for the hardened cement, such as to building materials and concrete products. The measurement results for the pore volume and specific surface area of the hardened low-heat cement indicated that the pore volume was considerably reduced and the specific surface area of the cement was increased after the carbonation. The calcium carbonate and the reaction ratios of the compounds in the cement were examined by X-ray diffraction (XRD) quantitative analysis and thermogravimetry-differential thermal analysis (TG-DTA). The hydration of alite and belite were accelerated by carbonation. The composition change in the hardened low-heat cement, which was caused by the carbonation, was studied using the results of the quantitative analysis. The mechanism which enables carbon dioxide to permeate hardened cement was examined by comparing the pore volume of hardened cement measured using a mercury porosimeter, with the pore volume of hardened cement determined from the composition change.

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The flow and bubbles motion in BaO-P₂O₅ or BaO-P₂O₅-Sb₂O₃ glass melts in a high magnetic field up to 2.0T was observed. No apparent change of flow characteristics in BaO-P₂O₅ glass melts was found. However, the frequency of bubble nucleation evidently decreased with the field strength. At a field strength of 2.0T, almost no nucleation of bubbles was observed. The majority of the bubbles were annihilated at the surface of the melt. This effect may apply to many optical quality glasses to be obtained bubble-free.

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Correlations have been investigated between centrifugal consolidation properties and flow characteristics of alumina slurries, prepared with polymeric dispersant and with pH adjustment. Attention has been paid to the deformation behavior of particle network structure in order to identify the main factor governing the consolidation process. For both slurry systems, final packing fraction and delay time observed in the centrifugal consolidation test can be well correlated with the yield stress and Bingham plastic viscosity of flow curve, respectively. It is shown from the experiments using several molecule weight polymers that deformation of polymeric dispersant affects consolidation process of slurries prepared with polymer molecules having the length comparable to primary particles. It is also suggested that wet shaping process of ceramics should be analyzed from the point of view of relationships between applied stress on particles and particle interactive force, instead of apparent viscosity of original slurry.

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Adsorption characteristics of proteins on Ca₈H₂(PO₄)₆⋅5H₂O (OCP) were investigated by liquid chromatography using a potassium phosphate buffer (KP) as an eluant. Proteins as sample molecules with different isoelectric point (pI) values were adsorbed on the OCP surface equilibrated with 0.01mol·dm^-3 KP, and were desorbed with increasing KP molarity. Basic proteins with pI>6.8 were eluted by a using KCl or MgCl₂ linear molarity gradient, whereas acidic proteins with pI<6.8 were not eluted even at 0.3mol·dm^-3 KCl or MgCl₂. Such a chromatographic behavior was similar to that of Ca₁₀(PO₄)₆(OH)₂(HAp). It is presumed that acidic and basic proteins were adsorbed on the Ca²⁺ ions (Ca site) with positive charge and the PO₄^3- ions (P site) with negative charge on the surface of OCP, respectively. The amount of Ca site on the OCP surface were considered to be more than that on the HAp surface from average elution molarities for acidic and basic proteins. As the crystal surface structure of OCP (h00) was similar to that of HAp (h00), acidic proteins were preferentially adsorbed on the (h00) of OCP crystal with a blade-shaped form.

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The coloration behavior of the inorganic/organic hybrids prepared from polydimethylsiloxane (PDMS) and chemically modified metal alkoxides was investigated by ultraviolet-visible (UV-VIS), X-ray photoelectron (XPS) and electron spin resonance (ESR) spectroscopies. Although the hybrids were transparent in the visible region, a broad absorption was observed from the visible to UV regions, leading to a color from yellow to wine-red. The color and the absorption edge of the hybrids depend on the inorganic components derived from metal alkoxides. XPS study showed the presence of a specific chemical state of metallic ions in the inorganic components derived from metal alkoxides. The XPS study revealed that a certain amount of metallic ions in the inorganic components derived from metal alkoxides is present in a specific chemical state that is distinct from a simple oxide. The ESR study showed the presence of localized electrons in the inorganic components derived from metal alkoxides or in an organic compound produced by decomposition of ethyl acetoacetate (EAcAc). The localized electrons may be relevant to the coloration of the hybrids.

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The properties of five kinds of lithium ionic conductors, LiLaSiO₄, LiNdSiO₄, LiSmSiO₄, Li₂Zr(PO₄)₂ and LiAlSi₂O₆, as solid electrolytes were investigated by designing the solid electrochemical cells such as (-) air, Pt|lithium ionic conductor| Au, Li₂CO₃, CO₂, O₂ (+), for the CO₂ gas sensor. The electromotive force, EMF, of these sensors increased linearly with an increase in the logarithmic value of carbon dioxide partial pressure, in accordance with Nernst's law. It was suggested from the slope of Nernst's equation that the two-electron reaction associated with carbon dioxide molecule takes place at the detection electrode above 400°C. The 90% response times of EMF for all these sensors for an increase in CO₂ concentration were within 2min at 450°C.

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The SiO₂-ZnO-B₂O₃-Na₂O system glass with various composition was coated on lead telluride (PbTe) surface in order to improve the oxidation resistance of PbTe. The oxidation behavior of the glass-coated PbTe was investigated by measuring the mass change during oxidation, and the effect of PbO⋅TeO₂ addition to the glass was discussed. Microcracks were observed in the SiO₂-ZnO-B₂O₃-Na₂O glass coating on PbTe surface. The addition of PbO⋅TeO₂ to the glass reduced the microcracks and improved the adhesion of the glass to PbTe. The mass change of the glass-coated PbTe decreased with increasing PbO⋅TeO₂ content in the glass. The PbTe specimen coated by the glass containing 60mass%PbO⋅TeO₂ showed no mass changes at 773K for 360ks.

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