The situation of research and development of chemical solution routes to superconductors is reviewed, Chemical solution processes were compared with the processes using solid state-derived powders in terms of the processing factors affecting the critical current densities (J_c) of superconductors. Though powders derived by chemical solution methods have better characteristics than those derived by solid state processes, these improved characteristics have not been reflected in J_c, the level of which remains much too low for practical use. The low J_c value is due to high porosity and weak links at grain boundaries; this problem has not yet been solved. It is necessary to pursue two approaches in the development of chemical solution processes. One is to combine with processes that have already been developed to fabricate high J_c superconductors, applying the characteristics of chemical solution-derived powders (fine and uniform particles). Another is to fabricate high J_c superconductors by the solid state sintering method using ultra-fine and highly sinterable powders derived from chemical solution methods. The former is expected to be in practical use within several years and the latter will be necessary in long-range research and development.

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To prepare the ceramics suitable for the immobilization of soy sauce yeast cells, vitrified-bonded alumina ceramics were fabricated, and the activity of cells inside ceramics was examined by the repeated batchwise fermentation.
The vitrified-bonded alumina ceramics which had average pore diameter of about 4-5 times of a cell dimension showed the best suitability for the immobilization. Cells in ceramic pores was realized to ferment feed solution more than 5 times. The fermentation with the ceramics as a support of soy sauce yeast cells was proved to be effective judging from the cell activity, the fermentation time and the ethanol yield factor.

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Properties of permeable magnesia refractory containing titania and alumina powder in the matrix were investigated in order to produce permeable refractory with high thermal shock resistance, corrosion resistance and low penetration of molten steel, By adding titania and alumina powder in the matrix, bright glossy portion and dark glossy portion were observed in the matrix and in the grain boundary of magnesia, Bright glossy portion was CaTiO₃ (Perovskite) from X-ray diffraction and EPMA analyses, Dark glossy portion was suspected to be Al₂TiO₅ (Aluminum Titanate) from EPMA analyses although Al₂TiO₅ was not detected by X-ray diffraction. The collapse of magnesia grains was caused by the generation of CaTiO₃ and Al₂TiO₅ in the magnesia grain boundary. Apparent porosity, mean pore diameter and permeability became high and large as TiO₂/Al₂O₃ molar ratio decreased, and reached the maximum value at the equivalent molar ratio. However, above the equivalent molar ratio the values became low and small. Permeability was proportional to the product of apparent porosity and the square of average pore diameter, Thermal shock resistance increased twice compared with no addition of TiO₂/Al₂O₃. Although corrosion resistance deteriorated by adding TiO₂/Al₂O₃. it was superior to the conventional porous alumina refractory, Penetration thickness of molten steel was not dependent on TiO₂/Al₂O₃ addition, and was very small compared with conventional one. This permeable magnesia refractory will have a good possibility of being used on actual operation.

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The reactivity of Ba₂YCu₃O₇ to metal oxides and carbonates was studied to develop a substrate material for superconducting oxide films, The superconducting oxide of Ba₂YCu₃O₇ reacted with most of the conventional substrate materials to form oxide compounds. BaZrO₃, SrCO₃, and CaSiO₃ were less reactive to Ba₂YCu₃O₇, and the onset critical temperature of Ba₂YCu₃O₇ remained unaltered after heating with these materials at 1223K. Zero resistivity temperature (T_c (end)), however, decreased depending on these materials. Coexistence of the substrate materials during heating increased the amount of oxygen vacancies in Ba₂YCu₃O₇, resulting in an increased lattice constant of c axis of Ba₂YCu₃O₇, The substrate materials for preparing high T_c superconducting oxide films require no interaction with the amount of oxygen vacancy of Ba₂YCu₃O₇ in addition to the low chemical reactivity to Ba₂YCu₃O₇, CaSiO₃ and BaZrO₃ were excellent substrate materials.

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Factors affecting cracking of porous glasses during leaching have been confirmed experimentally for two different composition glasses under leaching condition in which only leached or unleached layer shows cracking, When a glass exhibits swelling during leaching, cracks are developed in the unleached layer due to the generation of tensile stress in it. In contrast, when a glass shows shrinkage, the tensile stress generated in leached layer leads to cracking of this layer. To reduce this tensile stress, it is assumed to be very important that Na₂O in the SiO₂-rich phase is not be extracted and that SiO₂-gels in pores are removed. Experimental results showed that H₂O-leaching satisfies these requirements even for glasses which showed cracking due to swelling or shrinkage during typical acid leaching. In fact, a large amount of SiO₂-gels did not stay in pores and Na₂O was not extracted by H₂O leaching. It was noticed, however, that in further leaching with acid solution sometimes cracks developed in leached layer, depending on the glass compositions and heating conditions.

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A new method has been developed to determine in-situ the oxygen content in the superconducting Ba₂YCu₃O_x phase in equilibrium with the oxygen atmosphere from 0.2 to 10atm. The oxygen content was determined by the pressure change in a closed system due to the oxygen evolution from the sample at room temperature and high temperature, The results obtained at the lower pressure showed a good agreement with those determined by other methods. Ba₂YCu₃O_x absorbed some amount of oxygen during cooling in spite of a high cooling rate for the high pressures of oxygen.

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As to builder effect in synthetic detergent, the gelatinous precipitate was prepared by adding mixed solutions (Al/(Al+Si) molar ratio 0.17-0.83) of sodium silicate and sodium aluminate into hard waters (0.6×10^-3-12.0×10^-3 Ca²⁺ mol dm^-3). The capturing and its mechanism of calcium ion in suspension (pH 7-11) of the gelatinous precipitate were investigated as against synthetic A-type zeolite (Na₂(Al₂Si₂O₈)⋅4.5H₂O) used as a common builder, Characteristics of the gelatinous precipitate after capturing calcium ion were determined by X-ray diffraction, infrared spectroscopy, chemical analysis, dissolution test, measurements of specific surface area and ion-exchange capacity. The capturing capacity of calcium ion in suspension (pH 10-11) after adding the mixed solutions into hard water of 12.0×10^-3 Ca²⁺ mol dm^-3 increased remarkably against those of individual solutions. In a mixed solution having Al/(Al+Si) molar ratio of 0.5, the calcium ion in hard water was captured up to 95% in a shorter time as against the synthetic A-type zeolite. The composition of gelatinous precipitate after capturing calcium ion was formulated as Ca (Al_1.4Si_1.7O_6.5)⋅5.2H₂O. Also results of infrared spectrum and dissolution of calcium ion in water of the gelatinous precipitate showed that most of the calcium ion was strongly captured to the precipitate. Moreover most of the captured calcium ion as about 70% was exchangeable with sodium ion, That is, in the earlier stage of the reaction after adding mixed solution into hard water, a low crystalline precursor as familiar synthetic A-type zeolite was formed and changed finally to a low crystalline precursor like zeolite (gismondine) indicating as Ca(Al₂Si₂O₈)⋅4H₂O by ion exchanging of Na⁺→Ca²⁺. While, the effect of concentration of hard water and pH in suspension on capturing ability of calcium ion were investigated from a practical view. It was apparent that the capturing ability of calcium ion was almost equal to that of synthetic A-type zeolite in the case of the concentration of hard water (0.6×10^-3 Ca²⁺ mol dm^-3) as city water at pH 7-8.

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Alumina fibers were prepared by two new precursor methods based on the systems of Al(OPrⁱ)₃-Citric acid-H₂O and Al(OPrⁱ)₃-AlCl₃-Citric acid-H₂O. In the former system, precursor fibers were obtained from a viscous solution in a compositional region of Al(OPrⁱ)₃ mol/citric acid mol_??_1.25. In the latter system, they were obtained from a viscous solution in two compositional regions, one was a region of 6_??_total Al mol/citric acid mol_??_30 and 1_??_Al(OPrⁱ)₃ mol/AlCl₃ mol_??_3, and the other was a region of total Al mol/citric acid mol_??_1.5 and 1_??_Al(OPrⁱ)₃ mol/AlCl₃mol. The citric acid plays a very important role in developing a good spinnable solution by promoting the decomposition of Al₁₃⁷⁺ polycation, by inhibiting three-dimensional polymerization of Al-O bonds and by combining with [Al(H₂O)₆]³⁺ and Al-containing polymer. The structure of the polymers and cations was investigated by ²⁷Al-NMR spectra. The intensity of the-4--6 ppm peak assigned to a AlO₆ poly-structure decreased with citric acid content, and that of 0 ppm peak broaden by the coordination of citric acid to [Al(H₂O)₆]³⁺ The compositional and structural conversion from a precursor fiber to alumina fiber was achieved from amorphous to α-phase through γ-phase. The alumina fibers obtained from the former process always separated into double layers of margin and core, and those from the latter process were very homogeneous. This difference is related to the citric acid content in viscous solutions.

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Highly c-axis oriented thin films with compositions of [(1-x)PbTiO₃+xMgO] (x=0.015-0.090) were prepared by the rfmagnetron sputtering method. A few physical and electrical properties of these thin films obtained were studied PMT thin films of 1μm thickness showed that the degree of c-axis orientation α were approximately 0.8 and independent of compositionx. On the other hand, from the relationship between α and film thickness on the PMT thin films with x=0.030, α showed a tendency to decreased with increasing film thickness. It is considered that these thin films are successfully grown with good heteroepitaxy on MgO substrates from the RHEED pattern of PMT thin film with x=0.030. A range of I∝Vⁿ, where n≥2, was observed at high electric field below 250°C in I-V characteristics. This was considered to be due to an effect of vacancy in thin films. Apparent activation energy U_a of PMT thin films agreed with those of PMT single crystals and direct current resistivity ρ of films exhibited rather large values compared with those of single crystals.

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The residual stress of metal-ceramic laminates prepared by solid state bonding was studied for coating with a linear expan-sion coefficient larger than that of a cylindrical substrate. Two typical models, inner and outer coated cylinders, were chosen for finite element method (FEM) analysis to investigate the effect of axial length of the cylinder on the residual stresses at the coating layer. The results indicated that the dimensionless residual stress at the coating layer decreased with increasing coating thickness ratio and Young's modulus ratio for inner and outer coated cylinders. The residual stress at the coating layer increased with increasing axial length of cylinder, and the tangential stress at inner coating layer increased with in-creasing axial length of cylinder. The tangential stress at the outer coating layer was always larger than the axial stress, which means that the longitudinal cracking can easily occur in comparison with the circumferential cracking. However, for E_c/E_s>1, the tangential stress at the inner coating layer smaller than the axial stress, which means that the cracking behavior depends upon Young's modulus ratio.

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Single crystals of alkali-metal gallotitanogallate (AGGTO); A_x[Ga₈Ga_8+xTi_16-xO₅₆] (A=K, Rb, Cs) with a new type of one-dimensional tunnel structure were grown by the flux method. The best grown AGGTO crystals were obtained by slowcooling a flux melt at 1300°C using a mixture of 20mol% crystal composition of (A₂O)₁(TiO₂)₁ (Ga₂O₃)₁ and 80 mol% flux composition of (A₂O)₁(MoO₃)_1.5. The grown crystals were fibrous form elongating the c-axis (or tunnel axis) with a length of 5-10mm and a diameter of 10-100μm. The crystal structure and its material design are described on the basis of combination of structure units of priderite and β-gallia. The characteristic IR spectra were observed as the two absorption bands of 400cm^-1 and 475cm^-1, and the former was assigned to a Ga (Ti)-O stretching mode and the latter to a Ga (Ti)-O-Ga(Ti) bending mode in (Ga, Ti)O₆ octahedra and GaO₄ tetrahedra.

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A fabrication process of multilayer thick film was discussed The film, consists of three-layered structure, was stacked with protective layers of Al₂O₃ against vapor attack on both sides of Y-TZP layer. Slip casting method was used to form a multilayer green body. The thickness of each layer in the green body was controlled on the basis of casting data which was calculated for Al₂O₃ and Y-TZP slips. To avoid fracture during in an ambient atmosphere, it was important to minimize differences in permeability and pore size between Al₂O₃ and Y-TZP layers. No cracking was observed in a multilayer-sintered body, when a densification rate of each layer in the early stage of sintering was equal. The dense multilayer thick film was obtained by firing at 1600°C for 2h.

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Hydroxyapatite was synthesized through the sol-gel technique using Ca(OC₂H₅)₂ and P(OC₂H₅)₃ as starting metal alkoxides. It has been found that the pH of the starting solution is one of the most important factors affecting the formation of hydroxyapatite, The sol-gel reaction rate, the reaction products and the crystalline phases precipitated in heated gels have depended mainly on the pH range of the solution, that is, whether the solution is alkaline (pH≥9), neutral (8≥pH≥6) or acidic (ph≤5). Only hydroxyapatite crystals are precipitated and no additional phases are found when gels derived from the solution of 6 to 8 in pH and more than 60% in water content are calcined above 600°C. The resultant hydroxyapatite crystals obtained have a plate-like structure of about 1000Å in size, resembling closely the hydroxyapatite found in living tissues.

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Sparingly soluble inorganic salts such as BaSO₄ and CaC₂O₄⋅2H₂O are dissolved by soaking with an aqueous suspension containing a strongly acidic ion exchange resin, hydrogen form (H-R). The dissolution proceeds by the cation exchange reaction and can be traced by monitoring pH, specific conductivity (k, mS/cm) and ion (s) concentration (s) in the eluent.
For the sake of simple operation and for avoiding contamination by foreign ions, the dissolution method, different from the conventional method in which mineral acid is used, may offer a promising technique to elucidate the reaction mechanism including cement hydration.
The present work was undertaken to find a clue on the cement hydration chemistry and dealt with the dissolution process of portland cement powders. The dissolution was studied by batchwise addition of H-R to aqueous suspensions of cement with different degrees of hydration. Changes in pH and k during dissolution were compared for three kinds of cement, and analyzed quantitatively to discuss the dissolution based on the variations of dissolved amounts of constituent species for a rapid hardening cement (RHC).
The results obtained are summerized as follows;
(1) Dissolved Ca(OH)₂ is exchanged preferentially with H-R accompanying steep decrease in both k and Ca²⁺. Sulfuric acid libereated from gypsum results in a predominant increase in k at the complete dissolution.
(2) Changes in pH, k, Ca²⁺(%) and SO₄^2-(%) are terminated by the addition of H-R of about ten times weight as much as cement powder used, then, a considerable solubility of molybdate reactive silicic (MRS) acid is observed.
(3) Complete dissolution of unhydrated cement is confirmed by 100% dissolution of MRS acid, whereas the dissolution decreases with increasing degree of hydration. White silica gel precipitates for hydrated RHC (80°C, 72-280h) after the complete dissolution, indicating that all of Ca in C-S-H gel is also adsorbed by H-R as cement minerals.
(4) Equivalent ionic conductivity of the MRS acid is estimated as low as 3.6S⋅cm²/mol. The result indicates that the MRS acid does not contribute to the increase in k during the dissolution as mentioned in (1).
(5) This method is a useful technique for monitoring hydration characteristics and chemical changes taking place during early hydration of cement.

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Using an experimental piston type extruder, the extrusion characteristics of clays from Westerwald deposits in West Germany were compared with those of a domestic Kibushi clay. Both clays showed a linear relationship between the logarithm of extrusion pressure and solid volume fraction with similar gradients. It was found, however, that the clay from the Westerwald deposits can be formed under much lower pressure than that of the domestic Kibushi clay. Thus, the observed difference in extrusion behavior is probably dependent on the specific surface area, constituent minerals and the particle orientation during extrusion.

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Crystalline orientation and distribution in heat-resistant porcelain and glass ceramics containing some kinds of crystals with marked thermal anisotropy were studied with an X-ray microdiffractometer equipped with a curved position sensitive proportional counter. The surface of a porcelain plate for tableware contained predominantly crystallites of β-quartz solid solution with a little orientation. The quantity of β-quartz solid solution decreased rapidly with increasing distance from the surface, and the crystallites of indialite and enstatite with relatively even orientation increased to replace that of β-quartz solid solution. Crystallites of indialite and enstatite distributed uniformly in the interior more than 200μm from the surface. It suggests a possibility of improvement in the capability against thermal shock by reducing the crystalline size and increasing the homogeneity of the crystallite distribution in the vicinity of the surface. Almost the same X-ray microdiffraction patterns of β-eucryptite were obtained from any position of a plate of transparent glass ceramics containing β-eucryptite solid solutions as its crystalline constituent. Almost the same patterns of β-spodumene were obtained regardless of the position analyzed in a plate of white glass ceramics containing β-spodumene solid solutions. These facts indicate random orientation and uniform distribution of their crystalline constituents, which explain their superior resistance against thermal shock.

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Non-stoichiometric titanium nitride coating film was prepared on the SiO₂ glass substrate by ammonolysis of titanium dioxide coating film applied by sol gel method. The TiO₂ sol suitable for dip-coating was obtained by using diethanolamine as a stabilizing agent, when water and solvent were mixed in the molar ratio of 3:5. The TiO₂ coating film thus obtained was converted to titanium nitride by heating at 1100°C under the flow of NH₃ gas. The obtained titanium nitride film was fairly sensitive to air at temperatures above 400°C and gradually transformed to TiO₂.

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Four-point bending dynamic fatigue tests were carried out at five different crosshead speeds from 5×10^-4 to 5×10⁰mm/min in air at room temperature. Hot pressed silicon nitride ceramics was used for the tests and ground with 600, 400 and 200 grit resin bonded diamond wheels perpendicular to the direction of bending stress. Both the specimens ground with the 400 and 200 grit wheels showed a decrease in the fatigue parameter and fracture strength, while no decrease was observed in the specimen ground with the 600 grit wheel. It is suggested that grinding induces surface flaws and that the mean fracture strength of specimens ground with the 400 and 200 grit wheels tested at low crosshead speeds is lowered by slow crack growth of the surface flaws which are easily affected by stress corrosion.

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