窯業協會誌
Online ISSN : 1884-2127
Print ISSN : 0009-0255
ISSN-L : 0009-0255
82 巻, 950 号
選択された号の論文の10件中1~10を表示しています
  • 土谷 敏雄, 森谷 太郎
    1974 年 82 巻 950 号 p. 515-521
    発行日: 1974/10/01
    公開日: 2010/04/30
    ジャーナル フリー
    The electrical conduction and dielectric relaxation of some glasses in the system Na2O-MnO-P2O5 were studied over the temperature range 20°-180°C. This system contains Na2O confering an ionic conductivity on glass and MnO confering an electronic conductivity.
    In this study the electrical conductivity and dielectric properties were measured on both samples ordinarily cooled and properly heat treated. The results were discussed by considering the dependency of the composition, especially of the ratio MnO/P2O5, on the conductivity. In this series xNa2O-(50-x)MnO-50P2O5 the conductivity decreased with increasing the ratio MnO/P2O5, i.e. with decreasing Na2O content. In the non-alkali glass series xMnO-(100-x)P2O5 the conductivity showed to have a maximum value at the MnO/P2O5 ratio of about 0.67. The heat treatment was found to affect greatly on the conductivity. The linear relationship between log σ and 1/T was found in the glass containing a large amount of MnO, but the linear lines bent into two straight lines in the samples subjected to a proper heat treatment at a high temperature. The activation energy (ΔHdc) of glasses of the formula xNa2O-(50-x)MnO-50P2O5 was obtained by replacing MnO with Na2O. The curve representing the relation between the activation energy and the composition was found to show a minium at the composition near x=25mol% and a maximum near x=30mol%.
    The dielectric relaxation was observed by changing frequency and temperature. The frequency fmax at which the dielectric absorption shows a maximun was seen to shift toward a higher frequency with the increasing amount of Na2O. The relationship between σ and the frequency at which the dielectric loss indicates a maximum, fmax, follows the equation proposed by H. Namikawa but in the heat treated glasses this equation does not hold.
  • 猪股 吉三
    1974 年 82 巻 950 号 p. 522-526
    発行日: 1974/10/01
    公開日: 2010/04/30
    ジャーナル フリー
    Silicon nitride, Si3N4 and silicon oxynitride, Si2N2O are synthesized by nitriding highly pure and fine powder of silicon and silicon mixed with silica under atmospheric pressure of nitrogen in the range from 1400° to 1450°C. Heating experiments are performed with these samples in the range from 1530° to 1730°C in N2 atmosphere of 1 atm, and the change of composition is studied by X-ray diffraction. Pressed pellet of powdered mixture of α-Si3N4 and SiO2 shows a tendency to transform to β-Si3N4 by the heating. In these while, the formation of Si2N2O is observed together with large weight loss of the samples. Si2N2O changes to β-Si3N4 accompanying with the weight loss based on the evaporation of gas phase having nearly equal composition to SiO and nitrogen.
    It is concluded from the results of experiments that the stable compound in the system, Si-N2(1 atm)-O2 changes in the order, β-Si3N4→Si2N2O→SiO2 according to the partial pressure of oxygen being increased. α-Si3N4 is unstable under these conditions. It is also mentioned that the gas phase, SiO has an important role in the oxidation process of Si3N4 and Si2N2O sintered articles at such elevated temperatures.
  • 雨宮 政博
    1974 年 82 巻 950 号 p. 527-531
    発行日: 1974/10/01
    公開日: 2010/04/30
    ジャーナル フリー
    Effects of addition of fluorides, MnF2 and FeF3⋅3H2O, on the sintering of Mn1.29Fe1.71O4 ferrite compact and magnetic properties of the fired ferrite body were studied by measuring the fired bulk density, grain size, B-H curve (magnetic hysteresis curve), ferrimagnetic Curie temperature, saturation magnetization and crystal lattice constant. The results obtained are as follows.
    1) By addition of the fluorides, grain size and bulk density of the fired ferrite body became larger.
    2) No fluorine was contained in the fired ferrite body, since all the amount of fluorine had been liberated during the firing.
    3) No ferrimagnetic Curie temperature, saturation magnetization and crystal lattice constant being intrinsic properties of ferrite were changed with addition of the fluorides.
    4) By addition of the fluorides, magnetic hysteresis characteristics depending on the compactness of the ferrite materials were changed, i.e., magnetic flux density became larger and coercive force became smaller.
  • 林 国郎, 西川 友三, 上井 勲
    1974 年 82 巻 950 号 p. 532-537
    発行日: 1974/10/01
    公開日: 2010/04/30
    ジャーナル フリー
    The hot wire method has been used to measure thermal conductivity of massive solid materials. In order to find out a suitable way to measure thermal conductivity of granular solid materials, Ks, by hot wire method, the authors have examined the thermal conductivity measurement about the system of dispersed granular solid materials into a solid dispersion medium like silicon rubber. However, there were some limitations in the method that silicon rubber didn't work well at higher temperatures than 300°C and the rubber penetrated into the pore of granular solid materials in some cases. In this research, the authors tried to use some fluids to be applicable at higher temperatures and not to react with granular solid materials, and developed a method to be able to calculate Ks from gross thermal conductivity of granular solid-fluid mixture, K, and that of Kf.
    For the calculation of Ks from K and Kf, de Vries'equation was reasonably applied to both spherical and irregular-shaped particles. The shape factors Gi included in de Vries'equation were found to vary with the surface area of the granular solid materials in the case of spherical particles, but was almost constant in the irregular shaped particles.
    They were
    G1=G2=5.34×10-4S+0.0374 G3=-1.07×10-3S+0.925} for spherical particle,
    G1=G2=0.05, G3=0.90 for irregular shaped particle,
    where S is surface area (cm2/cm3)
    The reliability of the results obtained by the application of de Vries' equation increased with the use of fluid having higher thermal conductivity. For example, when helium gas with thermal conductivity of 3.65×10-4cal/cm⋅sec⋅°C was used, the error of the obtained values Ks of 3.25×10-3 and 1.4×10-2cal/cm⋅sec⋅°C were about 4% and 8%, respectively.
    In view of the fact that the error increased with increasing thermal conductivity of granular solid materials to be measured, this method can be applied to the solid materials having thermal conductivity of smaller than about 1.5×10-2cal/cm⋅sec⋅°C, if the error of ±10% is allowable.
  • 山本 和直, 熊田 虔, 並河 洋
    1974 年 82 巻 950 号 p. 538-545
    発行日: 1974/10/01
    公開日: 2010/04/30
    ジャーナル フリー
    Electric conduction and dielectric properties of the bismuth borate glasses were determined over the entire region of homogeneous glass formation (31-80 Bi2O3mol%). The electric conduction is affected by water in the glass. The glasses containing the least amount of water could be obtained when reagent grade chemicals of Bi2O3 and B2O3 were melted in the vacuum furnace.
    The results on the electric conduction are summarized as follows:
    1) The temperature dependence of conduction was given by
    ε=ε0exp(-ΔHdc/kT)
    in which ε is conductivity, ΔHdc activation energy of conduction, T absolute temperature, k Boltzman's constant and ε0 constant. The activation energies increased from 1.12eV (80Bi2O3mol%) to 1.59eV (31mol%). The values of ε0 were about 103ohm-1cm-1.
    2) The dielectric rlaxations with very long relaxation time were observed and the relaxation frequency was given by
    fm=fm0exp(-ΔHac/kT)
    in which ΔHac is activation energy of relaxation and fm0 constant. The values of fm0 were about 1013Hz. The following correlations were obtained between the conduction and the dielectric relaxation,
    ΔHdcΔHac
    ε≅2πε0Δεfm
    in which ε0 is dielectric constant of free space and Δε magnitude of the dielectric dispersion.
    3) The conductivity decreased as the pressure increased and the frequency of dielectric relaxation was shifted to lower frequency side.
    The obtained values of ΔHdc, ε0, ΔHac and fm0 were compared with those of the glasses of three different types (alkali oxide glasses, transition metal-containing oxide glasses and chalcogenide glasses). And it was found that those values of bismuth borate glasses were agreed very well with those of the alkali oxide glasses. As described in 3), the conductivity decreased as the pressure increased. The investigations on the pressure dependence of conduction show that the conductivity of alkali oxide glasses decreases by applying pressure, while that of electronic conducting glasses increases. From the facts described above, we concluded that the conduction mechanism of bismuth borate glasses is ionic. From the composition dependence of conductivity and the calculated values of carrier concentration from Δε, the conduction mechanism was ascribed to Bi3+ ion migration and not to proton or a trace of alkali ion migration.
    On the basis of the experimental results on dielectric properties the following problems were discussed, 1) polarization mechanism, 2) electronic polarizability of Bi3+ ion and 3) the temperature dependence of dielectric constant.
  • 小林 弘旺, 尾山 竹滋
    1974 年 82 巻 950 号 p. 546-553
    発行日: 1974/10/01
    公開日: 2010/04/30
    ジャーナル フリー
    The rate of dissolution of polycrystalline zircon in molten iron-oxide at 1500°C was studied under conditions of free and forced convection by rotating cylindrical zircon specimens in a stationary crucible containing the melt.
    Zircon specimen was about 20mm in diameter and 30mm long of about 25 percent apparent porosity. The specimens were rotated for 5 to 90 seconds at speeds of 0 to 800rpm in the melt. Then, the dissolution rate in molten iron-oxide at 1400°C to 1600°C was studied at 100rpm. The dissolution rate was calculated from the change in radius of the specimen.
    The dissolution rate in molten iron-oxide was extremely higher than both that of refractories in slag for manufacture of pig iron and that of alumina in molten iron-oxide. It was proportional to the square root of the speed of rotation, and it was dependent on temperature of the melt. There fore, we obtaind the view that the process of dissolution of zircon in molten iron-oxide under the conditions of this investigation is controlled by diffusion in the liquid boundary layer. Activation energy for the dissolution was about 80 kcal per mol. The interdiffusion coefficient was estimated to be about 1.7-8.5×10-3 sq. cm per sec at 1400°C to 1500°C.
  • 安井 至, 山口 悟郎
    1974 年 82 巻 950 号 p. 554-557
    発行日: 1974/10/01
    公開日: 2010/04/30
    ジャーナル フリー
    One of the most acceptable mechanism of spinel formation on sapphire in MgO-Al2O3 solid-state reaction is proposed on the basis of the crystal structure and other data. Although the mechanism of the sapphire-grown spinel formation has been explained in terms of topotaxy, the details have not been proposed nor discussed.
    The proposition about the reaction processes is shown as follows:
    (1) A small amount of MgO disolves into sapphire.
    (2) The oxygen stacking sequence is reconstructed from hcp to ccp by the partial dislocation mechanism.
    (3) This reconstruction accompanies with the synchro-shear movement of metal ions.
    (4) Mg2+ and Al3+ ions exchange their positions by inter-diffusion through the spinel lattice, and the total number of metal ions in the sapphire side increases.
    (5) The metal ions move to their proper positions of spinel structure, and then, the disordered spinel is formed. Displacement vectors of metal ions for this transformation were estimated.
    (6) The disordered spinel changes into that having the ordered structure.
    The validity of this proposition is discussed.
  • 萩原 尚男, 小山田 了三
    1974 年 82 巻 950 号 p. 558-563
    発行日: 1974/10/01
    公開日: 2010/04/30
    ジャーナル フリー
    Dielectric constants and infrared and Raman spectra of Na2O⋅SiO2-PbO⋅SiO2 glassy system were measured with change in PbO content. The value of dielectric constant increased from 8.0 (Na2O⋅SiO2 glass) to 15.5 (PbO⋅SiO2 glass) with the increase in PbO content, but the value showed little variation in the ranges of 0-30mol% PbO and at about 35mol% PbO which corresponds to the composition of the congruently melting compound (C. M. C.), 2PbO⋅Na2O⋅3SiO2.
    IR spectrum of Na2O⋅SiO2 glass showed two kinds of absorption bands at 9.5μ (1053cm-1) and 13.2μ (758cm-1) which correspond to the absorption bands of SiO2 glass at 9.1μ and 12.7μ, respectively. The band at 9.5μ shifted toward longer wavelength side with the increase in PbO content, but the shift of the band was not observed in the vicinity of C. M. C. composition.
    Raman bands of Na2⋅SiO2 glass were observed at 530, 780cm-1, and 1095cm-1. The band at 1095cm-1 corresponds to that of SiO2 glass at 1060cm-1 and it would be assigned to the triply degenerated stretching vibration of SiO44--tetrahedral structure. This correspondence may be interpreted as follows: the strength of Si-O bond can be increased by releasing of oxygen edges of SiO44- network unit by O2- ions from Na2O, and then the wave number of SiO44- tetrahedral vibration shifts toward higher energy side, i.e. from 1060cm-1 to 1095cm-1. The band at 1095cm-1 also showed the chemical shift with the increase in PbO content and the trend of its shift is in agreement with that of IR band at 9.5μ.
    From the fact that the value of D. C., the wavelength of IR band, and the wave number of Raman band keep approximately constant in the vicinity of C. M. C. composition, it can be said that the glass corresponding to C. M. C. holds a stable structure, though the arrangement of the unit (SiO44- etc.) of the network structure is in disorder.
    It may be said from the polarization measurement of Raman spectra that the glassy state of the system holds the characteristic features of the liquid state fairly well.
  • 大田 陸夫, 功刀 雅長
    1974 年 82 巻 950 号 p. 564-568
    発行日: 1974/10/01
    公開日: 2010/04/30
    ジャーナル フリー
    Glasses in the system As-Se were heat-treated at temperatures higher than Tg (glass transition temperature) for 20-340 hours in order to study the relation between the crystalline phase formed in a glass and the structure of the glass.
    The crystalline phases formed during the thermal treatment were identified by X-ray diffraction technique as hexagonal Se in the case of Se glass and As2Se3 in the case of As2Se3 and AsSe glasses.
    The crystallization of Se glass, which was initiated by homogeneous nucleation, was determined by density change, but heterogeneous crystallization was observed in As2Se3 glass and the crystal growth was measured by means of metallurgical microscopy as functions of temperature and time.
    The activation energies for nucleation (EN) and for crystal growth (EG) calculated from the Arrhenius plots of the induction periods of crystallization and the growth rate G are as follows; EN=29.4±0.8kcal/mole and EG=12.6±2.2kcal/mole for Se glass, and EN=41.2kcal/mole and EG=26.7kcal/mole for As2Se3 glass. They turned out to be much smaller than the activation energy for viscous flow at constant pressure or than the cleavage energy of a single bond such as Se-Se bond (44kcal/mole) or As-Se bond (42kcal/mole.).
  • 1974 年 82 巻 950 号 p. A51-A54
    発行日: 1974/10/01
    公開日: 2010/04/30
    ジャーナル フリー
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