Coated particles were prepared by the raw material injection method. Mica was used as the core particle, and Al(NO₃)₃, TiCl₄, SnCl₄ and ZrOCl₂ were used as raw materials for coating layers. The simple injection method (SI: injection of one of these raw materials), two-stage injection method (TI: injection of raw material solution in the order of Al(NO₃)₃ and one of the other raw materials (SRM: SnCl₄, TiCl₄ or ZrOCl₂)) and the mixed solution injection method (MI: injection of mixed solution of Al(NO₃)₃ and SRM) were applied, and the following results were obtained.
(1) It was possible to coat mica by the SI method when SnCl₄, TiCl₄, or Al(NO₃)₃ was used as the raw material. They were transformed into cassiterite, rutile or γ-Al₂O₃ by calcination at 700°C, respectively.
(2) It was not possible to confirm the formation of a coating layer on the product obtained using the SI method when ZrOCl₂ was used as the raw material.
(3) The morphology of the coating layer surface was affected by the kind of raw materials used when coating was performed using the SI method, and the tendency was almost the same as those of the MI and TI methods.
(4) For the products obtained using the MI method, simultaneous precipitation of Al and Sn compounds was expected when Al(NO₃)₃ and SnCl₄ mixed solution was used as the raw material solution. On the other hand, the Al compound seemed to precipitate earlier than the other salts when TiCl₄ or ZrOCl₂ was used as SRM.
(5) When Al(NO₃)₃ and TiCl₄ were used as raw materials, the coating layer seemed to form a double-layer when they were prepared by the TI method, and a mixed composite layer when prepared by the MI method.

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Alumina-Zirconia-Graphite (AZG) refractory is one of the most important refractory for AISI 304 stainless steel strip casting, especially used as slide gates or nozzles. A suitable particle size distribution desired by simple R(c/m) values, weight of coarse Al₂O₃ (500-1000μm)/weight of medium Al₂O₃ (61-125μm), is important for controlling the apparent porosity, which affects the thermal shock resistance and erosion resistance as well. The size modulus, R(c/m), has been shown to be a useful parameter for the evaluation of particle packing, as controlled by the particle size distribution, on various properties of the Alumina-Zirconia-Graphite refractory. The lowest apparent porosity (5%) and highest bulk density (3.5g/cm³) were obtained at R(c/m) value of 6.0. The relation of bulk density (D) with R(c/m) can be represented by D=-0.040R² (c/m)+0.351R(c/m)+2.741 for R(c/m) 0.4 to 3.7, and D=-0.006R²(c/m)+0.080R(c/m)+3.272 for R(c/m) 3.7 to 13, respectively. The average pore size (P_s) with R(c/m) value is expressed as P_s=0.035R²(c/m)-0.554R²(c/m)+7.138. The average pore size (P_s) of AZG refractory decreased from 6.5μm to 3.1μm, as the R(c/m) increased from 0.4 to 6.0. The number of air exposure cycles for the thermal shock resistance (R_st) were 14-17, and the relation of thermal shock resistance with R(c/m) is correlated by R_st=0.160R²(c/m) -1.371R(c/m)+16.860 for R(c/m) 0.4 to 3.7, and R_st=0.007R²(c/m)+0.277R(c/m)+13.082 for R(c/m) 3.7 to 13, respectively. The thermal shock resistance decreased gradually as the R(c/m) value was increased from 0.4 to 3.7. The effect of apparent porosity (P_o) on the erosion fraction (E_r) is expressed by E_r=0.233 Po+1.204.

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An analytical technique to determine residual stress in eqitaxial thin film by asymmetric X-ray diffraction (XRD) was studied. The residual stresses of PbTiO₃ films were determied by XRD technique and displace measurement technique. Measurement results by these techniques were compared with each other to consider the respective advantages of each technique. The stresses measured by XRD technique were not consistent with those by displacement measurement technique, because the latter technique involves errors which origined from the shape and the size of the substrate. The stress in a polycrystalline film measured by modified sin²ψ method was in good agreement with that measured by normal sin²ψ method. This result suggests that modified sin²ψ method can be applied to stress measurement not only in epitaxial thin films, but also in polycrystalline thin films. We further discuss the precision of the stress determination technique. Residual stress of epitaxial PbTiO₃ film on (100)SrTiO₃ substrate measured by modified sin²ψ method was comparable to the theoretical stress estimated from the difference in thermal expansion coefficients between the film and the substrate. Stress values measured by modified sin²ψ method may thus have the precision required for actual application.

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Three kinds of Si₃N₄ powders, DW, TX and E10, with and without sintering additives were ball-milled using ethanol as medium. Oxygen and carbon contents in the mixed powders increased due to the mechanochemical reaction between the powders and ethanol. The increases of oxygen and carbon were almost the same for the three powders. After heat treatment at 800-1200°C in vacuum or nitrogen gas, most of the carbon was desorbed. On the other hand, the increment of oxygen remained in the ceramic body even after sintering at 1750°C.

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Molecular dynamics (MD) simulation was carried out on the high Li ion conductor, La_0.6Li_0.2TiO₃, using the partially ionic model (PIM). MD simulation of the Li ion conductivity with the variation of mobile ion size under high pressure revealed that this compound had the optimum lattice size for Li ion conduction and that the skeletal lattice was too small for Li⁺ ion to show the highest conductivity.

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Dense silicon carbide matrix composite reinforced by Hi-Nicalon^® with BN or BN/SiC coating was fabricated by slurry impregnation of carbon and SiC and subsequent reaction sintering with molten Si. The optimum sintering condition was investigated and the effect of BN layer thickness on the tensile strength at room temperature was evaluated. The composite which was uni-directionally reinforced by 30vol% fibers with BN/SiC coating of 1.0/0.3μm thickness and sintered at 1693K for 0.3ks showed Young's modulus of 242GPa, the ultimate tensile strength of 556MPa and the failure elongation of 0.9%. The ultimate tensile strength showed a good agreement with the prediction from in situ fiber strength via fracture mirror size.

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Manufacturing process of glass-ceramic produced from waste granite was investigated for use as a construction material. Waste stone crushing is usually difficult, so waste stone is heated to 700°C in an electric furnace, then cooled rapidly with water. Successively, the stone is crushed into particles smaller than 297μm. Crushing and classification is repeated until over 90% of the waste stone product is reduced into fine particles. Batches were prepared by mixing a mass ratio of 100 fine particles waste stone, 50-60 limestone (CaCO₃), 5-15 soda-ash (Na₂CO₃), 3-8 anhydrous sodium sulfate (Na₂SO₄), 0.7-1.5 graphite (C) and 0-4 zinc oxide (ZnO). Black glass was produced by melting the batch at 1450°C in an electric furnace, and allowed to flow on a steel plate. To form a nucleation, this glass was reheated at 850°C for 1h and reheated at 1050°C for 2h to form a glass-ceramic. Results of scanning electron microscope observation and powder X-ray diffraction of the obtained glass-ceramic showed β-wollastonite (CaO⋅SiO₂) to be the main crystal structure; this is composed of about 2-3×10-20μm prismatic crystals that are homogeneously entangled.

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The perovskite-type solid solutions Sr₂(Sr_1-xM_x)TaO_z (M=Ca, Nd) were synthesized. Lattice distortion and cation ordering in the octahedral site of the perovskite type structure were investigated using Rietveld analysis of powder X-ray diffraction data. Cubic perovskite-type phases with cation ordering in octahedral site were obtained for Sr₂(Sr_1-xCa_x)TaO_5.5 (x=0-1), and Sr₂(Sr_0.9Nd_0.1)TaO_5.55. Two types of monoclinic perovskite-type phases were obtained for Sr₂(Sr_1-xNd_x)TaO_z. The unit cell of the solid solutions for x=0.3-0.7 was close to a tetragonal cell. The distortion of the solid solutions was due to tilting octahedra and a difference in the direction of tilt was observed between the compounds for x=0.3-0.7 and x=0.9-1.0. Degree of monoclinic distortion increased with increasing Nd³⁺ content. Cation ordering in the octahedral sites was observed in all the compositions investigated for Sr₂(Sr_1-xNd_x)TaO_z. Increase of Nd³⁺ content possibly causes increase of oxygen content z. The present results suggest that increase of oxygen content is one of the reasons to cause the lattice distortion for Sr₂(Sr_1-xM_x)TaO_z (M=Ca, Nd).

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LiNbO₃ thin films with c-axis orientation were deposited on polycrystalline Si₃N₄ substrates by means of RF-magnetron sputtering method. Response ability to cyclic stress of the Si₃N₄ specimen coated by LiNbO₃ thin films was evaluated by a 3-point bending fatigue test. The voltage range produced by LiNbO₃ thin films increased linearly with the maximum stress during the cyclic test. The voltage range depended on the frequency of cyclic stress. The position of cyclic compressional load was revealed due to the different generations of voltage signals at a multielectrode placed between the LiNbO₃ thin film and Si₃N₄ substrate.

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The formation rate of hydrous-zirconia fine particles produced by the hydrolysis of various ZrOCl₂ solutions (with and without an addition of NaCl, CaCl₂ or AlCl₃) were measured to investigate the effects of added metal chlorides on the formation rate. Chemical analysis and X-ray diffraction measurements revealed that the hydrous-zirconia particles synthesized in the present experiments contained little Na, Ca and Al, and were similar to those observed in monoclinic crystalline zirconia. Chemical kinetics analyses revealed that the formation-rate constants (k) of hydrous-zirconia particles, under constant ZrOCl₂ concentration, decreased with increasing NaCl, CaCl₂ and AlCl₃ concentrations. The decrease in the formation rate upon addition of the above metal chlorides can be explained by the decrease of the k(I)-term in the ionic strength function contained in k, and the blocking action of the hydrolysis attributed to the ligand-substitution reaction between H₂O molecules coordinated to Zr atoms and Cl^- ions.

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Polycrystalline samples of YRh₃B_x, YRh₃C_x and YRh₃B_xC_1-x have been synthesized by arc melting method to clarify the relationship between the lattice parameter and boron or carbon content. All the obtained perovskite-type compounds have cubic structure (space group: Pm3m, Z=1). Perovskite-type YRh₃B_x exists in the range 0.444≤x≤1.0. Lattice parameter a in YRh₃B_x depends on x, and varies from 0.40944(6)nm (x=0.444) to 0.41675(5)nm(x=1.0). Perovskite-type YRh₃C_x also exists in the above range of x. Its lattice parameter a varies from 0.40855(5)nm(x=0.444) to 0.41262(4)nm(x=1.0). The packing mode of the boron and carbon in the host lattice of YRh₃ are very similar; the value of the lattice parameter a increases with increasing the amount of interstitial atoms of boron or carbon, x. In the case of solid solution perovskite-type YRh₃B_xC_1-x, lattice parameter a also depends on x, with being 0.41428(6)nm (x=0.25), 0.41462(5)nm(x=0.5) and 0.41506(5)nm(x=0.75); the a vs. the x does not follow the linear function.

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Highly dispersed Ni powders for based metal electrode (BME) for multilayer ceramic capacitors (MLC), prepared by carbonyl process and wet chemical process, have been realized by means of noble pulverization and dispersion technique. Carbonyl Ni powders have relatively large particle size and a strong oxidation-resistance property. Therefore, they are suitable for BME with small capacitance MLC with low active layer (>100 layers). On the other hand, wet chemical process Ni powders poses fine particles size and they are suitable for large capacitance MLC with high active layers (<100 layers). It is obvious that a narrow distribution particle size and highly dispersed Ni powders developed by the pulverization and dispersion technique make them ideal to realize thin layer BME for MLC.

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Reaction and sintering characteristics of mixtures of kaolin (Al₂O₃⋅2SiO₂⋅2H₂O) with BaCO₃ or SrCO₃ were investigated using kaolin and finely ground carbonate powders. Although the decomposition temperature of barium carbonate and strontium carbonate are higher than 1050°C, both carbonate powders decomposed at much lower temperature of about 800°C and then reacted with decomposed kaolin to form amorphous materials. Thus formed amorphous materials are extremely sinterable, and pressed specimens can be rapidly sintered at about 950°C by viscous flow. Densification is inhibited by the immediate crystallization of hexacelsian crystals (SrO⋅Al₂O₃⋅2SiO₂, or BaO⋅Al₂O₃⋅2SiO₂) at about 1000°C. Further densification was not observed at temperatures above 1000°C, because of completion of the crystallization of amorphous phases. Amount of SrO or BaO for sufficient sintering were larger than n=1.2 and n=1.6, respectively, with n being the mol ratio of SrO/Al₂O₃ and BaO/Al₂O₃. The reason of the difference in the n values was attributed to the difference in viscosity between the amorphous phases. Dense polycrystals consisting of mainly monoclinic Sr-celsian were obtained at about 1200°C.

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Effect of alcohol solvent in mixing process on the microstructure and sintering behavior of ceramic-based composites was investigated in detail. The mixture of fine ceramic powders was prepared through the conventional ball-milling method with various alcohol media. The particle distributions of fine ceramic powders were strongly dependent on the kind of alcohol employed during ball-milling. Ceramic-based composites were fabricated by hot-pressing the mixture of fine ceramic powders. Their microstructures and some mechanical properties of the ceramic-based composites were evaluated. It was found that the viscosity of alcohol, surface tension and contact angle greatly affect the sinterability and some of the mechanical properties of ceramic-based composites.

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Concerning the pull-through defect, which is a sort of defect of the glass-lining, the following two inspection methods were investigated. One inspection method is to detect the fluorescent pull-through defect by adding a fluorescent substance to the ground coat. Another inspection method is to detect the difference in color between the pull-through defect and the cover coat under a sodium lamp, as a monochromatic light source. This latter method utilizes the difference in the absorption coefficient of the light of the sodium lamp between the pull-through defect and the cover coat. In case of the luminescence substance addition, the fluorescence is not detected after 3-h firing and the cost of products increases 20% because of the expensive luminescence substance. Therefore it is difficult to apply the luminescence substance addition to the inspection method. In case of the phosphor addition, the fluorescence is detected after long firing and the cost of products increases under 0.5%. In case of using the sodium lamp, it is necessary to take the conventional light source or 450nm monochromatic light source together with the sodium lamp to distinguish between the pull-through defect and a large bubble. The phosphor addition and the sodium lamp utilization are useful as a pull-through defects inspection method.

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In order to fabricate porous ceramics with uni-directionally-arranged continuous pores, alumina compacts containing nickel wires as a pore forming agent were prepared by casting the alumina slurry on the plaster mold, on which nickel wires were settled and uni-directionally arranged with applying a magnetic field. Acid-leaching the nickel wires and subsequent sintering the samples resulted in the formation of continuous and straight pores in dense alumina matrix. Size of continuous pores could be varied with using nickel wires with different size. Interval between pores could be controlled by coating the nickel wires with alumina prior to the arrangement in the magnetic field. Electrophoresis technique was useful to form a coated layer with controlled thickness.

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Clay roofing tiles have been widely used for roof of detached houses. After the Hanshin·Awaji great earthquake, there is a sharp decrease in demand for clay roofing tile, because it's weight per unit area is the heaviest among all kinds of roofing materials. In the development of a light clay roofing tile with high mechanical strength, it is not convenient to use raw materials of high grade due to an increase of the production cost. In this study, the usually employed raw materials, which contained a large fraction of quartz grains with large size, were ground by wet ball milling, and the influence of the maximum quartz grain size on the mechanical strength of the roofing tile bodies was studied. Upon grinding the quartz of raw material to a smaller grain size, a roofing tile body with high mechanical strength could be obtained. The flaw size for mechanical strength of the roofing tile body seems to mainly depend on the maximum quartz grain size.

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Thermal treatment of lanthanum acethylacetonate dihydrate (LAA) in toluene in the presence of a small amount of water at 300°C was examined and the product was characterized by ¹³C-NMR, FT-IR, thermal analysis and scanning electron microscope (SEM). Only acetoxy group (CH₃COO-) was confirmed by the NMR measurement and hydroxyl group (-OH) was also observed in addition to the acetoxy group in the FT-IR spectrum, indicating the LAA was hydrolyzed and the acetylacetonate group was decomposed under the present condition. From the results of thermal analysis and elemental analysis, the product was determined to be lanthanum diacetate hydroxide (La (CH₃COO)₂(OH)). SEM observation revealed that the product consisted of thin plate while LAA was bulky mass, suggesting that the product was formed via a dissolution-recrystallization mechanism.

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Oriented thin films of La_1-xSr_xMnO₃ were prepared by spray-ICP (inductively coupled plasma) technique. An aqueous solution of metal nitrates, as starting material, was partially decomposed to the constituent atoms and ions in the plasma. Different reactivity of these species with oxygen resulted in a deviation of the composition of the film from that of the mother solution. The composition of the mother solution was adjusted to obtain films with a desired composition. (001) oriented films (based on the orthorhombic system) with flat surface were obtained on (100) MgO substrates. The film consisted of particles, coalesced together so close that the grain boudaries were not resolvable. The temperature dependence of the electrical conductivity of the films exhibited semiconductor-semiconductor transitions for the films with x≤0.25, semiconductor-metal transitions for the films with x=0.28 and 0.3, and a metal-metal transition for the film with x=0.5. However, the transition temperatures were different from those reported for the single crystals. The transition phenomena changed drastically by heat treatment in air, suggesting that oxygen stoichiometry (total metal/oxygen ratio) critically influences the electrical properties. The semiconductor-metal transition took place at x=0.27 for the low temperature phase of the (001) oriented film and randomly oriented film. The transition composition is different from the composition (x=0.17) reported for the single crystal low-temperature phase, but close to that for the single crystal high-temperature phase. The grain boundaries as well as the oxygen stoichiometry appear to influence the electrical properties.

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