Pulse radiolysis was applied to the lithium-, sodium- and potassium-silicate glasses. The obtained spectra in micro and milli second ranges were the same as those observed by steady state X-ray irradiation at cryogenic temperature. The peak energies increased with a decrease in the radius of alkali ion. The lifetimes of these transient components were relatively long. In one second after irradiation the spectra of lithium and sodium silicate glasses resemble those by X-ray irradiation at room temperature, while the additional absorption due to trapped electrons located on the potassium ion remained in the same time range. The absorption due to the transient components in the sodium silicate glasses decreased with increasing temperature as well as by doping an electron scavenger such as Cd(II) ion. The emission due to recombination of the electron centers with some hole centers was reduced by the presence of Cd(II) ion.

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The internal friction and electrical properties of glasses in 40Fe₂O₃⋅60P₂O₅ system were measured. The quantitative values of dynamic modulus G′ and dynamic loss G″ on internal friction were obtained by considering the shape factor. G′ was 3.0×10⁹-1.0×10¹⁰dyn/cm², and G″ was 1.0×10⁷-5.0×10⁷dyn/cm² in the range of valence ratio (R_e=Fe²⁺/Fe²⁺+Fe³⁺)R_e=0.13 to R_e=0.37. The two peaks were observed in the temperature range from -100° to 400°C at a frequency of about 1Hz. The area of the low temperature peak (at about 0°C) increased with increasing valence ratio R_e similar to that in the D. C, conductivity and dielectric increment. All of internal friction peak and electrical properties showed maxima at R_e=0.5. Frequency temperature dependence of the dielectric loss peak and low temperature peak on internal friction showed a straight line and its activation energy was 0.55 eV. The internal friction peak in glasses of 40MgO⋅60P₂O₅ system was not observed in the temperature range -100° to 200°C. From the above results the peak observed at low temperature was due to the hopping of localized electron in small polaron. On the other hand, the activation energy of high temperature peak was about 1.6eV (37kcal/mol) and the high temperature peak decreased with increasing R_e ratio, Consequently, the peak observed at high temperature was considered as due to the interaction between proton and non-bridging oxygen ions.

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Origin of the purple color of chromium-containing SnO₂(Cr-SnO₂) was studied mainly by ESCA, ESR and diffuse reflectance spectroscopies. It was found that when the Cr₂O₃ content in Cr-SnO₂ was higher than 1.5wt%, the color of Cr-SnO₂ is not purple but green due to the presence of Cr³⁺ in the aggregate state. ESCA and ESR analyses of the chemical state of chromium in Cr-SnO₂ revealed that Cr⁶⁺, Cr⁵⁺ and Cr³⁺ are minor species when the Cr₂O₃ content in Cr-SnO₂ was about 0.2wt%. Addition of Al³⁺ or Sb⁵⁺ to Cr-SnO₂ gave rise to absorption bands at about 450 and 600nm or 470 and 650nm respectively, indicating that Cr⁵⁺ and Cr³⁺ in Cr-SnO₂ are not responsible for the purple color (570nm). Consequently, the broad absorption band at 570nm was considered to be produced by Cr⁴⁺.

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The dehydration rate of silicon nitride slurry in slip casting process was measured. The dehydration rate was calculated based on Darcy's law and Carman-Kozeny equation. The values necessary for calculating the dehydration rate, such as viscosity of the suspension medium, surface area per unit volume of the dehydrated layer, capillary pressure of the plaster of Paris, volume fraction of the ceramic particles and thickness of the dehydrated layer, were experimentally determined. The calculated dehydration rate agreed well with the experimental results when 6.2 was assigned to the Kozeny constant implying that the rate limiting process in slip casting is the transportation process of suspension medium in the dehydrated layer.

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Phase separation behavior in sodium borosilicate glasses has been examined by measuring the electrical conductivity of glasses above T_g and by observing the phase-separated glasses with a transmission electron microscope (TEM). The Arrhenius plot of conductivity shows a break point when glass undergoes phase separation, which is attributed to changes in the sodium-ion concentration and mobility of a continuous phase in the phase-separated glass. TEM observation confirmed that the break point falls on the immiscibility temperature. The conductivity curve indicates whether the (Na₂O-B₂O₃)-rich phase is continuous or not. The volume fraction of each phase and the electrical conductivity are constant throughout the particle growth. On the base of the change in the conductivity, the composition of Na₂O-rich phases was estimated and the tie lines were determined therefrom for a few glasses.

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Six kinds of Si₃N₄ starting powders which were mixed with 6wt% Y₂O₃, 2wt% Al₂O₃ and 3wt% MgO as densification aids, were pressed and normally sintered at 1550°-1650°C. The sintered compacts were HIP'ed without capsule in a nitrogen atmosphere of 100MPa at 1700°C. Density, flexural strength and α-to β-phase transformation were studied. The results obtained are summarized as follows:
(1) Density and strength of HIP'ed Si₃N₄ compacts were strongly affected by characteristics of starting powders such as specific surface area, green density and amount of α-phase.
(2) The mean strength of sintered compacts of which starting powder had a specific surface area of 14.2m²/g and contained 97% α-phase, increased from 370 to 870MPa by HIP treatment.
(3) Improvement of strength depends on α-to β-phase transformation and the formation of fibrous grain in Si₃N₄ compacts during HIP treatment.

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The authors reported the thermally stimulated current (TSC) and thermo luminescence (TL) of γ-irradiated radiation shielding glass in I. C. G., 1966. The present paper is concerned with the details of the report. From the data, it has been clarified that the thermal functions of negative and positive charges which are produced in the surface region by γ-irradiation are as follows.
(1) When the glass surface is irradiated by X- or γ-ray from one direction, the surface is positively charged because electrons produced by photon-electric or Compton effect have a momentum to the inner part of glass.
(2) Therefore, it is considered that thin electric double layer is produced in the surface layer of which field strength depends on the γ-ray dose, initial photon energy and on the electrical property of the glass.
(3) By heating the irradiated glass, the trapped electrons released in the vicinity of the electric double layer drift forward to the positively charged surface, because TSC is observed at lower temperature than temperature of positive ion conductivity. According to the content of luminescent impurity atoms, TL is also observed. The mechanism of electric breakdown of shielding glass is clarified when it is exposed by γ-ray for a long time. The above considerations, showed that thermal annealing is an important process to prevent the accumulation of electric charges in the glass.

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This investigation was carried out to study the change in X-ray diffraction patterns observed in Mn-Co-Ni oxides heat-treated at high temperatures. The samples were prepared by firing the oxides of Mn, Co and Ni with molar ratio of 3.0:1.9:1.1 between 1000° and 1400°C. In the X-ray diffraction study, the change of diffraction patterns, which seemed to be due to same crystal structure change, was observed in the samples fired above 1140°-1160°C. To examine these crystal structure changes, EPMA study was made on the sample heat-treated at 1200°C. The distributions of Mn, Co and Ni were heterogeneous and the two phases, Mn-rich and Ni-rich, were observed. The quantitative analyses of Mn, Co and Ni contents were made by EPMA on these two phases. The samples with the same compositions as those of the analytical values were newly prepared by firing at 1200°C. X-ray diffraction study on these newly prepared samples proved that the Ni-rich phase had a rock salt structure and that the Mn-rich phase was estimated to have a spinel structure of composition (Co, Mn) [Mn, Co]₂O₄ in which some cation were substituted by Ni. These results proposed that the change in X-ray diffraction patterns was attributed to the phase separation of cubic spinel into tetragonal spinel (Mn-rich) and rock salt (Ni-rich) phases.

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Unidirectional carbon fiber/glass-like carbon composites were prepared at 1000° to 3000°C. Thermal diffusivity, heat capacity and thermal conductivity were measured by the laser flash method at room temperature to 700°C. For all of the composites, thermal diffusivity decreased with increasing temperature. The high heat-treatment temperature decreased the thermal diffusivity. Heat capacity of all composites increased monotonously with increasing temperature. Thermal conductivity of the composites heat-treated below 2400°C showed a maximum value between 300° and 500°C. For the composite heat-treated above 2600°C, thermal conductivity decreased with increasing temperature. These phenomena were correlated with the crystallites size of layer structure in the matrix.

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Porous glass prepared by acid leaching of phase separated glass contains colloidal silica, resulting in the nonunif ormity in the porous glass. Porous glass rods were impregnated with aluminum nitrate solutions, and some of them were treated subsequently with ammonia to precipitate aluminum hydroxide. Then the porous glasses were sintered to form nonporous glasses. The concentration profile of aluminum in the sintered glasses was studied with reference to the nonunif ormity. The aluminum concentration in the impregnated and ammonia-treated specimens was high at the surface region and decreased toward the center. This fact coincides with the distribution of porosity which is high at the surface region. The concentration difference between the as-impregnated and impregnated and ammonia-treated specimens was large at the center and decreased toward the surface, in good correlation with the distribution of the surface area which is high at the center. A narrow gap with a low aluminum concentration was observed at the center of the impregnated specimen and was ascribed to the very densely deposited colloidal silica.

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Photo-catalytic deposition of fine Pd particles on diamond particles and subsequent electroless coating with Ni were studied, Fine Pd particles could be deposited by photo-irradiation in spite of the smaller energy of incident light (<3.9eV) than E_g of diamond (5.47eV). They have higher activity for the electroless coating of Ni than those deposited by means of the usual 2-liquid type sensitizing method. The resulting Ni layer was uniform and adhered closely to diamond particles. For good distribution and adherence of the Pd deposits, surface pre-treatment was very effective. Ethanol and i-propanol were suitable as a reducing agent for dense deposition, and the reaction temperature of 35°C was best. The density of the Pd particles seems to be determined by reduction of Pd²⁺ ion with an intermediate alcohol radical rather than by that with the photo-excited electron.

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Brazing of pressureless-sintered SiC to stainless steel using Ag-28wt% Cu alloy was studied, In SiC plate joined to stainless steel rod (6mm in diameter) using an Ag-Cu alloy powder containing 1.5wt% Ti, the bond strength increased with decreasing brazing temperature and holding time. When the increased size of stainless steel plate (10×10×4mm), joining was unsuccessful by the method mentioned above and even with Ti insert-metal. However, simultaneous use of Ti and Mo as insertmetal gave a good bonding in the order SiC/Ti/Mo/stainless steel, because of relaxation of residual stress due to thermal expansion mismatch. The shear strength was 30-50MPa. A thin layer, probably Ti₃SiC₂, was observed at the interface between SiC and brazing filler immediately after melting. But with increasing both temperature and time, Ti₅Si₃ (C) and TiCx were formed if Ti was continuously provided from the brazing filler. Since the interface of Ti₃SiC₂ and eihter Ti₅Si₃ (C) or TiC_x seemed to be brittle, the formation of Ti₅Si₃ (C) and TiC_x decreased the bond strength. At lower temperature and short time, a high bond strength is expected when Ti was inserted in contact with SiC.

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Ca[Zn(OH)₃]₂⋅2H₂O is precipitated by mixing NaZn(OH)₃ aqueous solution (0.1mol/l) with CaCl₂ solution(0.1mol/l). It decomposes to monohydrated calcium hydroxide and zinc oxide above 140°C.

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The relationship between a content of semiconducting powder and an electrical property of the glaze was analyzed considering of microstructural differences in electrical conducting channels. Those channels are formed by three dimensional connections of a high conductive layer surrounding a semiconducting particle. Fair coincidence between measured conductivity and calculated one was found in the range of V_e≤V_t by Hanai model and in the range of V_e>V_t by Keller's cylindrical model for this glaze system.

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