The temperature dependence of contact electric resistance of metal powders dispersed in epoxy resin and in many glasses was studied in relation to the thermal stress at the metal-metal contacts.
Besides the hot pressed composite test specimens using powdered materials, a model specimen was prepared by sealing two pieces of a same metal wire in a tubing glass in vacuum.
The contact electric resistance of the sealed metal wires or the dispersed metal particles having lower (higher) linear thermal expansion coefficient than those of matrices increased (decreased) exponentially on cooling, indicating the existence of compressive (tensile) stress along radial direction of the metal wires or particles and their release on heating. For the systems which had tensile stress the decrease of the resistance upon heating could be reasonably understood as the decrease of barrier for electron transfer through the metal-metal contacts due to the decrease of minute clearance between metal wires or particles. The electric resistance of the composites generally increased on cyclic heat treatment, which may resulted from the change of contact condition of metal particles due to the crack formation and/or crack propagation in matrices.

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Investigating some properties of casting layers in molds, the following results were obtained.
1) Inhomogeneous moisture distribution in cast pieces on draining resulted from the moisture gradient in cast layers which was proportional to the product of the fundamental parameters, [F₃⋅S_a⋅d_s], and from the thickness of remaining slip layers which could be expressed as a function of yield value, viscosity and drain angle.
2) Average solid volume fraction of cast pieces on draining, [F_c], was calculated from the equation F_c=(F_c′l+F₁Δl)/(l+Δl) where F_c′, F₁, l and Δl were solid volume fraction of cast layers, of remaining slip layers, thickness of cast layers, and of remaining slip layers, respectively. F_c′ was expressed by the equation F_c′={0.55/(1+S_a⋅d_s)-0.44}⋅F₃+0.01F₁.
3) In the case of solid casting, the average solid volume on bulding up of the cast layers could approximately be estimated by the above equation giving F_c′ value.
4) On draining or building-up of the cast layers the initial moisture content in cast layers rapidly decreased until mold separation stage having the solid volume fraction, F_D. It was suggested that workability of demolded cast pieces would depend upon the value of [(F_D-F_C)/F_D].
5) Dry linear shrinkage, Sh, could be expressed by the equation Sh=A(1-F_C/F₃) where A was a constant depending upon the anisotropy in shrinkage.

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The sinterability of RuO₂ has been studied by measuring the isothermal shrinkage of compacts and the surface area change in the temperature range of 800° to 1000°C in oxygen atmosphere. The mechanism of material transport was discussed on the basis of physico-chemical properties obtained from the measurement of decomposition pressure and of weight loss by sublimation.
It is elucidated that decomposition pressure of RuO₂ goes up to several torr at 1000°C and that sublimation occurs at higher temperature than at 1000°C in a stream of oxygen. It is presumed that the sintering of RuO₂ occurs by evaporation-condensation process in oxygen atmosphere.

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The species of crystallizing compounds, its precipitation temperatures and solidus temperature have been determined for the wide composition range of the SrO-B₂O₃-Fe₂O₃ system. By cooling the melts of the compositions of the following nominal molar expressions, (1-x)(SrO⋅3B₂O₃)-xSrO⋅6Fe₂O₃, (1-x)(SrO⋅2B₂O₃)-xSrO⋅6B₂O₃ and (1-x)(SrO⋅B₂O₃)-xSrO⋅6Fe₂O₃, Fe₂O₃ primarily crystallizes in Fe₂O₃ rich sides. For the serieses of (1-x)(1.5SrO⋅B₂O₃)-xSrO⋅6Fe₂O₃, (1-x)(2SrO⋅B₂O₃)-xSrO⋅6Fe₂O₃ and (1-x)(3SrO⋅B₂O₃)-xSrO⋅6Fe₂O₃, SrO⋅6Fe₂O₃ crystallizes primarily. Among those the 1.5SrO⋅B₂O₃ series is best for growth of the crystal, where the x value should be around 0.125.
The crystals obtained were hexagonally shaped thin plates; the maximum length of the hexagonal was about 1cm and the thickness was about 3mm. Atomic absorption sepctroscopy revealed that the boron atoms scarecely dissolve in the ferrite lattice (less than 0.02wt% at maximum).
It is found that, for the growth of the magnetoplumbite type ferrite crystals from the (nRO⋅B₂O₃)-(RO⋅6Fe₂O₃) melts (R=Sr, Ba, Pb), the optimum composition of nRO⋅B₂O₃ would be a little richer in RO content than that of the glass forming composition of the corresponding RO-B₂O₃ two component system.

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Glasses containing various amounts of aluminum and fluorin were crystallized by the heat treatment. Bending strengths of the crystallized glasses were measured, the crystalline phases were identified by X-ray diffraction method, and the microstructures were examined by electron-microscopy. The relation between the microstructure and the bending strength was studied.
The results obtained are summarized as follows:
1) The crystallized glass having the highest bending strength (42kg/mm₂) was obtained from the glass containing limited amounts of aluminum and fluorin under the optimum conditions of heat treatment.
2) The crystalline phases existing in the crystallized glasses were two kinds of fluoramphibole and two kinds of fluor-mica. The chemical composition of crystalline phases changed with that of the glass.
3) The differences of the grain size and the amount of each crystalline phase between the outor surface layer and the inner part of the crystallized glass were observed.
4) The thickness of the outer surface layer was about 150μ and especially the microstructure of the outer surface layer of about 10μ in thickness differed extremely from that of the inner part.
5) It was considered that the microstructure of the outer surface layer influenced dominantly on bending strength of the crystallized glass.

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