Joining properties of Al for two kinds of SiC bodies, reaction sintered SiC and pressureless sintered SiC, were examined. SiC bodies were joined at 800°C and 1000°C in vacuum using induction heating, and four-point bending strength of joins was measured in vacuum at high temperatures. Bending strength of joins was 10-25kg/mm² at room temperature, and 5-15kg/mm² at 400°C. Fracture modes of pressureless sintered SiC joins were ductile at high temperatures, while at room temperature it was brittle. As for reaction sintered SiC joins, free Si in the sintered bodies influenced on properties of joins, especially on strength of SiC bodies and interlayers.

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The effect of grinding of raw quartz on the hydrothermal reaction in CaO-SiO₂ system was investigated by using a small reaction vessel immersed in oil bath for rapid heating. Results obtained were as follows.
(1) It was found that reaction is generally accelerated by grinding, but that prolonged grinding retarded the reaction, especially, in the case of so long-time grinding as 24h, reaction hardly proceeded after 3h.
(2) The molar ratio (CaO/SiO₂) of the reacted composites was changed from 4.1 to 1.6 for unground quartz, and 0.3 to 1.9 for ground quartz.
(3) It was found that N value of the equation, (1-³√1-α)^N=kt, was 1.3-2 for raw quartz, and larger than 2 for ground quartz.
(4) Ca-ion concentration in water exceeded greatly than that of silicic acid after reaction.
(5) From the results of X-ray and TG-DTA analyses, C-S-H was the only compound formed, but the textures of the hydrates were very different from each other, namely, plate or needle crystals were observed for unground quartz, and long fibrous crystals were observed for ground quartz.
From these results, it was found that the reaction took place in a different mechanism by grinding treatment, and especially, the reaction with long-time ground quartz nearly stopped in a half way. This seems likely to be due to the fact that amorphous silica produced on the surface of the ground quartz reacted rapidly, and the further reaction was inhibited by the dense layer produced in its initial stage. Therefore, the influence of amorphous silica in quartz should be taken into accout on the hydrothermal reaction in CaO-SiO₂ system.

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The molecular dynamics calculations on halide glasses assuming ionic potential functions were made in order to obtain the correlation between the structure and the property. In this study, the results of computations on metastable liquid and glassy state of AgI and ZnCl₂ were presented. The structures of AgI glasses and melts from calculations were shown by the pair correlation functions g₂(r) for Ag⁺-Ag⁺, I^--I^- and Ag⁺-I^- pairs for T=3000K, 1187K, 327K and 247K. The splitting of the first peak for the like ion for g₂(r) was correlated with the splitting of the second nearest neighbour peak always observed for monoatomic glasses. In order to see the ionic motion, the computer-generated graphics were used. A close look of the trajectories for both kinds of ions revealed that the diffusion constant for Ag⁺ and its temperature dependence in liquids and glasses seemed to relate to the instability of the anion sublattice. By extending these computations, the statistical mechanics of glasses and the glass transition were obtained. The volume and enthalpy as functions of temperature were shown that sudden changes in the derivative of the volume-temperature and the enthalpy-temperature plot occurred in the region of 0.6T_m, which was similar to the experimental glass transition behavior. The change in C_p from 84.3J·K^-1·mol^-1 to 56.2J·K^-1·mol^-1 between liquid (1187K) and glass (327K) was of the magnitude of this discontinuity for ionic glasses [C_p(liq.)/C_p(glass)=1.2-1.8]. These changes in thermodynamic variables were associated with the virtual vanishing of the ionic diffusion coefficient, which was obtained from the slope of the mean squared displacement-time curve. The ZnCl₂ glass obtained in the glassy state by normal laboratory procedures was also computed and discussed in the same manner as AgI. Consequently, the phenomena related to the experimental glass transition could be manifested in computations.

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The bloating mechanism of expanded shales has been investigated by measurement of the gases generated during the calcinating process. Furthermore, the mechanism of fusion welding has been clarified from the structure of the expanded shales and the chemical analysis of iron. The results obtained are as follows.
(1) The largest bloating condition was obtained at calcination temperature above 1100°C heating rate above 40°C/min.
(2) As generation gases, H₂, CO₂, H₂O and CO were detected from the good bloating shale, but the poor bloating shale liberated H₂O and CO₂ only. It has been discussed that H₂ and CO in these gases were formed by decomposition of organic carbon contained into shales. Consequently, the good bloating state were indicated on the much organic carbonbearing shale, as well as on the poor bloating shale added organic carbon.
(3) The amount of generation gases decreased near melting temperature and increased above bloating temperature of shale.
(4) The structure of expanded shale was consisted of two layers with the interior and the outer shell. In paticular, this outer shell has been made of the thin heat-resistant film oxdized and sintered by oxygen in air atmosphere. Therefore it is available for the prevention of fusion welding between shales and kiln or shales.

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Rectangular parallelepiped resonance (RPR) method was applied for the measurements of elastic constants and their temperature dependences on SiO₂ glass and MgO single crystal with about 2mm in edge length. SiO₂ glass and MgO single crystal were cut in the shape of cube and rectangular parallelepiped, respectively. Each surface of MgO specimen was parallel or perpendicular to crystallographic axis determined by Laue back diffraction method within an accuracy of 0.5°. The transducers used were BaTiO₃ polycrystalline plates at room and low temperatures and LiNbO₃ single crystal plates at high temperatures. As the resonant frequencies increase with the increase of force imparted to the specimen held with two transducers, the resonant frequencies at which the force was extrapolated to the zero value were obtained. At low and high temperatures, the resonant frequencies were measured as the relative changes from the room temperature values. The measurements of resonant frequencies were made over the temperature range from liquid nitrogen temperature to room temperature on SiO₂ glass and to 800°C on MgO single crystal. The shear velocities determined from EV-1 and OD-1 modes and Poisson's ratio obtained from dimensionless frequency-Poisson's ratio diagram on SiO₂ glass at room and low temperatures were in good agreement with data determined by an ultrasonic interference method. It was shown that the use of dimensionless frequency-Poisson's ratio diagram for an isotropic solid was very useful and gave the reliable data. The elastic constants of MgO single crystal were determined by minimizing the differences between observed frequencies and calculated frequencies of 18 modes at room temperature. The temperature dependences were determined from the relative changes of resonant frequencies using 10 modes. The results were in good agreement with Spetzler's data. It was found that (1) even a small specimen of 2mm size could be used, (2) sample preparation was quite easy as compared with the ultrasonic technique, (3) the resonant frequency necessary for the measurement was low, and (4) the temperature dependences of elastic constants on both isotropic and nonisotropic solid could be obtained accurately by measuring the relative changes of resonant frequencies from the room temperature values, if the force imparted to the specimen was kept constant during the measurement of temperature variation.

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Selective response to Cu²⁺ ions was systematically studied for chalcogenide glass electrodes in the system Cu-As-Se. Copper-containing glass electrodes responded to Cu²⁺ ions while the electrodes containing no copper were insensitive to Cu²⁺ ions, suggesting that the presence of copper in the electrodes was an essential condition for sensitivity to Cu²⁺ ions. It was found that there was an optimum glass composition, Cu_0.10As_0.34Se_0.56, for the linearity between the electrode potential and logarithm of Cu²⁺ concentration in solutions and for the stability against various surface treatments; the electrode made of the above glass showed good Nernstian behavior with the slope of 30mV/decade in the concentration range of 10^-6 to 10^-2M of Cu²⁺ ions. This value of the slope implies that the potential-determining reaction is the two-electron process. Sufficient selectivity of the chalcogenide glass electrodes over several metal ions, such as Mg²⁺, Co²⁺, Mn²⁺, Fe³⁺ and Sn⁴⁺, was confirmed, while some metal ions such as Ag⁺ and Hg²⁺ would interfere with the sensing of Cu²⁺ ions.

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The behavior and properties of iron oxide in porcelain bodies were studied mainly by ESR. On increasing the firing temperature of a body for porcelain, an ESR signal due to bulky Fe₂O₃ appeared at about 300°C, reached to a maximum at 600°C and almost disappeared at 1300°C. The color of the fired body and the percentage of Fe ion removed by treatment with an oxalic solution correlated fairly well with this ESR intensity. Fe³⁺ contents of several porcelain bodies fired at 1300°C in air, measured by means of the usual chemical analysis were compared with the intensities of ESR absorption at g=4.25 due to isolated Fe³⁺ ion and the linear relationship was found between them. This linear relationship also held for the bodies fired under a reducing atmosphere. These results indicate that ESR is applicable to the direct quantitative analysis of Fe³⁺ ion in porcelain bodies, whether Fe³⁺ contents are high or not. Furthermore, an attempt to apply ESR to the quantitative analysis of Fe³⁺ contents of commercial ceramic materials was made but not successful.

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Magnesia cement grinding wheel is a special one bonded by magnesia cement. Magnesia cement is made from magnesium oxide (magnesia), magnesium chloride and water. After mixing these materials, the reaction of hardening progresses at room temperature. Examinations were tried for the regulation of heat evolution and for complete hardening after a short time on the manufacture of magnesia cement grinding wheels. Active seawater magnesia was selected by reason of short hardening time. Citric acid and magnesium sulfate were added for the regulation of heat evolution. The results are as follows. The bulk of grinding wheel without additives has an irregular microstructure with large pores and holds unstable free water. Shrinkage after hardening is small, but alkali chloride deposit considerably to the surface. By addition of small amounts of citric acid and magnesium sulfate, setting and heat evolution time of paste are retarded, and the paste temperature is lowered. Free water in the paste is fixed at the early stage of hardening. The hardened bulk has a fine and regular microstructure with somewhat small pores. Shrinkage increases, but deposition of alkali chlorides at the surface is little. Elastic modulus of the grinding wheel increases.

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