Two kinds of dumet wires (copper clad Fe-Ni alloy wires) with thick and thin copper oxide layer, were sealed into an alkali barium silica glass by heating moderately and excessively, respectively. Concentration distribution of elements along radial direction was measured by an electron probe microanalyzer.
The results were as follows:
1) The distance of diffusion front of copper from the surface of the wire was about 70μ and 30 to 40μ for excessively and moderately heated seal, respectively.
2) Barium showed peculiar distribution. Maximum and minimum points were formed at about 5 and 10μ distance from the surface of wire, respectively. The extremums were distinct in excessively heated seals.
3) Sodium and potassium showed flat distribution in glass except high concentration at copper-glass interfaces.
4) In moderately heated seals, copper oxide partly disolved into glass. The remainder seemed to behave as bridging layer between copper and copper-containing glass.
In Excessively heated seals, most of copper oxide diffused into glass. Very thin layer, however, was presumed to remain behaving as bridging layer between copper and copper-containing glass.

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Magnesia powders, which were obtained by calcination of synthetic magnesium hydroxide (99.9wt% MgO ignited basis) at the temperature range of 500 to 900°C, were hot pressed at 250kg/cm² in air. The pressure was applied at room temperature and maintained while the temperature was raised at a rate of 200°C/h up to 900°C. The shrinkage and the crystallite size of the powder compacts during hot-pressing were measured.
The results obtained were summarized as follows:
(1) In the hot-pressing of magnesia powders calcined at the temperatures lower than 800°C, the rapid shrinkage was observed at the temperatures below 700°C.
(2) The lower the calcination temperature of magnesium hydroxide, the lower the temperatures at which the rapid shrinkage took place.
(3) The rapid crystallite growth of magnesia was observed during the rapid shrinkage.

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The present investigation was undertaken in an effort to derive the theoretical densification kinetics of both systems, i.e., (a) monosystem of the orientated Newtonian viscous filaments and (b) polyphase system in which inclusion filaments are equidirectionally orientated in Newtonian filaments, in hot pressing under low external pressure.
In these systems, the continuous and uniform open pores are unidirectionally orientated through the whole stage of densification. The theoretical relative density can be expressed as a function of time as follows;
for the monosystem:
D={1+nπ[(2r₀η-γ_Nt)/(Pt+2η)]²}^-1…(2),
and for the polyphase system:
D={1+n_A′π[(2r₀η-γ_Nt)/(Pt+2η)]²+n_B′π[(2r₀η-Ft)/(Pt+2η)]²}^-1.…………(4)
The validity of Eqs. (2) and (4) was proved experimentally on a model system of same sized glass and/or inclusion filaments orientated in one direction. It was foundth at the F value in Eq. (4) relates linearly with the contact angle of the matrix glass and the inclusion.

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[in Japanese]

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This study was concerned with the formation and color development of the spinel solid solution in CoO-ZnO-Cr₂O₃-TiO₂-SnO₂ system, and its application to colored glazes.
Specimens were prepared by calcining the oxide mixture at 1400°C for 1hr. The formation of spinel solid solution was examined by X-ray diffraction, the color was discussed by measuring the spectral reflectance, and the stability of the spinel in glazes was tested.
The results were summarized as follows.
1) Formation of a continuous solid solution was confirmed by X-ray analysis.
2) As the amount of Cr³⁺ increased in ZnO-Cr₂O₃-SnO₂ system, the color changed from white through grayish olive green to grayish leaf, and the absorption of Cr³⁺ shifted towards violet region.
3) An increase of Cr³⁺ in ZnO-Cr₂O₃-TiO₂ system caused the color to change from white through leaf to grayish leaf, and the absorption of Cr³⁺ shifted towards violet region.
4) The color obtained in ZnO-Cr₂O₃-TiO₂-SnO₂ system ranged from leaf to yellowish green.
5) An increase of Cr³⁺ in CoO-ZnO-Cr₂O₃-SnO₂ system yielded the colors ranging from grayish leaf through grayish olive green to strong blue green, and the absorption of Cr³⁺ shifted towards violet region.
6) As the amount of Cr³⁺ increased in CoO-ZnO-Cr₂O₃-TiO₂ system, the colors ranging from dark yellow through olive to strong blue green developed, and the absorptions of Co²⁺ and Cr³⁺ shifted towards violet region.
7) As the amount of Ti⁴⁺ increased in CoO-ZnO-TiO₂-SnO₂ system, the color changed from grayish leaf through grayish yellow to dark yellow, and the absorption of Co²⁺ shifted towards red region.
8) The colors ranging from leaf to olive developed in CoO-ZnO-Cr₂O₃-TiO₂-SnO₂ system.
9) According to the result of the colored glaze test, formation of a new spinel was observed, and the specimens with the composition of Cr³⁺ rich region were stable as a glaze stain.

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The effect of Nb₂O₅ additive on the sintering of SnO₂ was investigated by measuring density, shrinkage and grain size in the temperature range 1200 to 1400°C in O₂, air and N₂. The sinterability of SnO₂ compacts was increased with Nb₂O₅ content, and at a concentration of 5wt% Nb₂O₅, high-density bodies of 95% of theoretical were obtained after sintering at 1400°C for 10hr in O₂. From electrical resistivity and X-ray diffraction data, it might be consideredthat niobium ion was soluble in SnO₂ up to about 3wt%. Electron microscopic observation of polished specimens showed that Nb₂O₅ second-phase particles inhibited the grain growth and grain growth kinetics could be described by D=kt^m; the values of time exponent “m” were found to be 1/4 and 1/6 for the specimens with Nb₂O₅ content of 3wt% and 5wt%, respectively.
In the initial stage of the sintering, relatively fast shrinkage occurred by addition of Nb₂O₅ without formation of liquid phase, and then Nb₂O₅ second-phase particles decreased the grain growth rate which dominated the sintering kinetics during the later stage.

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[in Japanese]

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