Raman spectra of glassy PbO-GeO₂ and PbO-B₂O₃ systems were measured and analyzed. For pure glassy GeO₂, several bands were observed at 300-600 (peak position: 410), 760, 860 and 970cm^-1. The bands at 410, 760 and 860cm^-1 were assigned respectively to ν₄, ν₁ and ν₃ mode of the vibration of the tetrahedral GeO₄ which has T_d symmetry. For PbO-GeO₂ system a new band appeared at 750-850cm^-1 and it could be separated into two bands by the polarization. analysis. One of these new bands, the band of higher energy, corresponding to the band at 860cm^-1 of glassy GeO₂, was found to shift toward a lower wavenumber with increasing PbO content. The wavenumber of this band showed a nearly constant value in the neighbourhood of PbO⋅GeO₂ composition. The similar shift of another band of lower energy was also found. The fact might be related to the 6-folded coordination of Ge in tetragonal GeO₂ (rutile type). Such a trend of band shifting found in Raman spectra is similar to that of the infrared absorption spectra previously reported by the authors.
For pure glassy B₂O₃, several bands were also observed at 450, 650, 806, 1260 and 1470cm^-1. The bands at 650, 806, 1260 and 1470cm^-1 were assigned respectively to ν₄′, ν₁′, ν₃′, and ν₃′ mode of the vibration of the triangular BO₃ which is D_3h symmetry. For PbO-B₂O₃ system, the bands at 1260 and 1470cm^-1 were united into a broad band and showed the shift toward a lower wavenumber with increasing PbO content, e.g. 1350cm^-1 for PbO 30mol% and 1245cm^-1 for PbO 70mol%, suggesting the effect of the interaction between Pb²⁺ ion and BO₃ group. A new band appeared at 1000-1150cm^-1, and could be assigned to ν₃ mode of BO₄ tetrahedral structure (T_d symmetry). The intensity of this band increased up to about PbO 50mol%, and then decreased with further increase of PbO. The fact might be related to the number of BO₄ structural units which are found in the system.
Based on the above assignments, we estimated the force constants in GeO₄ and BO₃ structural units by GF matrix method. The values of f_r, f_φ and f_rφ for GeO₄ were 5.45, 0.55 and 0.13 (mdyn/Å) and for BO₃ were 6.13, 0.80 and 0.76 (mdyn/Å), respectively.

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Observed packing behavior was compared with calculated results employing the author's method to a packed body prepared by stick penetration and a body obtained by press moulding and a fired body for magnesia refractory having the Andreasen colltinuous-grading under 4mm.
From the results, it was shown that the calculated particle-size distribution for a closest packing (q_ρm) of fired body were in good agreement with those of observation in the same behavior of the packed body by stick penetration and the press moulded body, and that the changing tendency in calculated packing density and q_ρm value with respect to intensification of a packing operation and increasing of fired temperature were also in good agreement with those of observation.
Also, it was shown that the unsaturated residual void accompanied with each constituent components obtained in the calculation process of packing density were in good agreement with observed tendency for the pore-size distribution of fired body.
From these results, it might be concluded that the author's method proposed for calculating the packed volume of multi-component particle-size systems is significant and useful to discuss the texture and structure of refractory, and the coefficient of particle-size distribution is also very important parameter to investigate the texture and structure of refractory.

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Rate of nitridation of chromium powder and Cr₂N-CrN equilibrium were investigated by a thermogravimetric technique (850-1250°C). The rate of nitridation was explained on the basis of nitrogen diffusion-control in Cr₂N layer formed on chromium particles.
For the reaction 2CrN=Cr₂N+1/2N₂, the equilibrium pressures were found to be expressed by logP(atm)=12.2-1.67×10⁴/T. The standard enthalpy of the reaction was calculated to be 38.2kcal/mol which was somewhat larger than those reported by other authors. The nonstoichiometry of Cr₂N phase was discussed.

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Specimens of semi-vitreous chinaware having various water absorption were repeatedly autoclaved at 10kg/cm² and the stress in the glaze was measured after each treatment. The initial compressive stress in the glaze increased with the decrease in the water absorption of the body, and the compressive stress decreased linearly with the hours of autoclave treatment when the logarithmic scale was used for the hours. The gradients of the curves of the stress against the stress treating time were almost the same, regardless of the difference in the initial stress.
Because of the linear relationship between the stress in the glaze and the hours of autoclave treatment, one can estimate the hours of treatment, after which the stress becomes zero, by only two measurements, that is, measurement of the initial stress and measurement of the stress after an autoclave treatment of a fixed time. This provides us with a rapid testing method for the evaluation of the delayed-crazing resistance.
By using this method of testing, one can not only rapidly estimate quantitatively the delayed-crazing resistance, but also obtain information about the initial stress in the glaze of the wares, and about the decreasing tendency of the stress against the hours of autoclave treatment. The information may be useful for the improvement and control of the delayed-crazing resistance of semi-vitreous chinaware.

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Thermal conductivities of the 27R-and 21R-pseudo-polytypes of AlN and aluminium oxynitride spinel made from mixed powders of AlN and Al₂O₃ by hot-pressing were measured as 0.015, 0.013 and 0.026cal/cm·s·K at 300K, respectively.
Effect of hot-pressing conditions on the thermal conductivities of AlN which was synthesized by reducing and azotizing alumina was investigated. The thermal conductivity decreased with increase of the oxygen content, especially at lower temperature near 300K. The thermal conductivity, however, varied not only with the amount of oxygen, but also with its distribution in the hot-pressed specimens. This is due to some crystalline phase transformation as the result of the solid reactions between AlN and oxygen containing crystal layers at elevated temperature.
In general, fine powder of AlN is covered with amorphous oxide layer of about 40-120Å. During heating, probably at above 1200°C, the amorphous layer begins to crystallize into corundum. The corundum reacts on AlN at above 1650°C to form aluminium oxynitride spinel with defect structure. The formations of these corundum and oxynitride facilitate the sintering of the powder remarkably. The oxynitride further reacts on AlN at above 1900°C to form 27R-pseudo-polytype of AlN.
The considerable decrease of the thermal conductivity in the temperature range from 1800°C to 1900°C suggests that the oxygen in the oxynitride which is supposed to be concentrated in rather narrow grain boundaries seems to spread widely into the AlN grains composing 27R structure.

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In order to collect fundamental data for manufacturing bone china by using bone phosphate, firing process of bone china bodies was investigated by conventional methods kinematically and microscopically. And bulk specific gravity, modulus of elasticity, transverse strength, translucency, and expansion coefficient for fired bodies were measured.
The results of linear thermal expansion and shrinkage in the specimens showed two distinct stages which shrinked at about 920°C and 1200°C or higher temperature. The shrinkage occurred at about 920°C seemed to accompany with diffusion, sintering process. The shrinkage observed at about 1200°C might be related to the densification process occurred by both viscous flow mechanism and melting process of crystal grains in bodies. Modulus of elasticity and transverse strength increased with spreading of melt through matrix phase and decreased with expansion of the pores at 1200°C or higher temperature. Translucency increased with spreading of melt through matrix phase and expansion coefficent decreased with melting of crystals.
In comparison with bone china body of using bone phosphate and that of using bone ash, the vitrification behaviour, microstructure, and natures of fired bodies were not so markedly chaged except the process of producing Ca₃(PO₄)₂ and anorthite at about 920°C.

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X-ray small-angle observation on some lignin-based and pitch-based carbon fibres is discussed with reference to the results of high-resolution electron microscopy, which have already been reported separately.
The results showed that the sizes of microvoids, as well as of the solid phase around them, increased with increase of heat-treatment temperature and that stretching of the fibre promoted their further increase. So far as the pitch-based carbon fibres are concerned, the microvoid size distribution proved to be almost independent when the sizes are normalized with the length of the radius of gyration; the shapes of the microvoids were found to be well approximated with oblate ellipsoids for the non-stretched fibres and with prolate ellipsoids for the stretched one. The microvoids in the lignin-based fibre were composed of two groups: one was almost similar to that of the pitch-based carbon fibres heat-treated at the same temperature, while the other was much larger in size and more complicated in their distribution.

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