Chemical compositions of beryllium sulphates precipitated from aqueous solution with various pH-values and thermal decomposition were examined by TGA and X-ray powder diffraction.
(1) Beryllium sulphates were classified four groups: (a) Beryllium sulphate tetrahydrate, normal salt, (pH_??_1.6); (b) Beryllium sulphate tetrahydrate with sulphuric acids, (0.5_??_pH_??_1.6); (c) Beryllium sulphate tetrahydrate solid solutions, (1.6_??_pH_??_2.5); (d) Basicberyllium sulphates, (2.5_??_pH_??_4.4).
(2) On quick heating, the normal salt and the solid solutions melted incongruently forming the dihydrate.
(3) As the SO₃/BeO value of the solid solutions and the basic beryllium sulphate decreased, dehydration temperature became higher than that of the normal salt. The dehydration temperature of the normal salt with sulphuric acid became lower than that of the normal salt.
(4) As the SO₃/BeO value of the solid solutions and the basic beryllium sulphates decreased, de-SO₃temperature became higher than that of the normal salt.

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The carbonation of several calcium aluminate compounds, constituting hydrated cement, was investigated individually. The samples of C₄AH₁₃, C₂AH₈, C₃AH₆, C₃A⋅3CaSO₄⋅H₃₂, C₃A and CA, synthesized from pure chemicals, were carbonated 100% CO₂ gas atmosphere (gas reaction), or by blowing 100% CO₂ gas into 100% water slurry (liquid reaction). Reaction rates, the fraction of the produced calcite in CaCO₃, and species and crystallinity of the cabonation products were examined by X-ray diffraction method and infra-red absorption method. The results obtained were as follows:
1) Carbonation of the hydrates is influenced by crystal type of hydrates, and the reaction rate is concerned with properties of reacted layer, which is determined by species of hydrates and crystallinity of the carbonation products. The reaction proceeds rapidly with C₄AH₁₃ and C₂AH₈ of meta-stable type, very slowly with C₃AH₆ of stable type, and rapidly with C₃A⋅3CaSO₄⋅H₃₂ of double salt type. The reaction products are calcium carbonate and hydatred alumina gel, and the calcium carbonate is characterized as amorphous.
2) Carbonation of the anhydrous compounds proceeds very slowly as compared with the reaction of hydrates, and even slowly with the anhydrous calcium silicates. Reactivity of the anhydrous compounds in carbonation is very small in contrast to the large reactivity in hydration. The difference of reactivity of anhydrous compounds is significant in analysing mechanism of carbonation.

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CeO₂単味物, TiO₂添加物の粒成長を1300°-1550℃の間で研究した. TiO₂が添加された時, 粒成長はD³=Ktにしたがい, 粒成長の活性化エネルギーは75kcal/molであった, CeO₂単味物の場合, D²=Ktで活性化エネルギーは110kcal/molであって, 液相の生成と新化合物CeO₂・2TiO₂の生成によってTiO₂はCeO₂の粒成長に効果を与える.

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従来, 提出されている初期焼結の速度式から, 一定速度で昇温した場合の速度式 (1) を理論的に導出した.
log(ΔL/L₀)^1/m-loglog A+Bt/A
=logK-E/R(A+Bt) (1)
この式の妥当性を検討するため, ZnO, NiOおよびFe₂O₃の焼結を昇温法でおこなった. 収縮の測定には差動偏位測定器を用い, また焼結過程での錠剤断面の状態を調べるために走査型電子顕微鏡などを用いて観察した. この結果, 粉体が球状に近い場合, 実験データーはきわめてよく式 (1) によってあらわされ, 式 (1) のプロットからえられる見掛けの活性化エネルギーが文献値とよく一致することを示した.

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The bending strength and microstructure were studied on the crystallized samples obtained from fluor-richterite composition glass by different heat treatments. The results obtained were as follows:
1) The best heating condition for obtaining micro-polystalline material was to heat the glass at 600°C for more than 8hr to cause the glassy phase separation and heat up to the crystallization temperature at a heating rate lower than 5°C/min. The glassy phase separation and the crystallization of layer-structure crystalline phase (intermediate phase) in the earlier stages of the heat treatment were found to influence the crystallization of fluor-richterite (main phase).
2) The glass could be converted to the translucent polycrystalline material of the highest bending strength (26-38kg/mm²) by heating the glass at 600°C for 16hr, heating up to 950°C at a rate of 2.5°C/min and then keeping at 950°C for 1-2hr.
3) The specimen having high bending strength consisted of a large amount of microcrystals of fluor-richterite under 0.1μ in size, a small amount of residual glass and a small amount of the other crystalline phase (clino-enstatite) which was found on the surface of the specimen.

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An initial-stage sintering of a sinterable BeO has been studied by using a rapid heating method. Through observation of microstructures on the densification by a scanning electron microscopy, the initial-stage sintering was found to proceed by the following mechanism;
(1) In the initial stage of the sintering from 46% to about 57% of T. D., neither grain growth of primary particle nor formation of neck between these particles were observed, and voids formed between particles on the pressing were found to be rapidly fulfilled. This indicates that the initial-stage sintering was controlled by a rearrangement process of primary particles.
(2) At the end of the initial-stage sintering, primary particles were coalesced to form secondary particles.
(3) Secondary particles were made from about fifty to a hundred of primary particles, and they were nearly identical in size, whose diameter was about several times of primary particle.
(4) Secondary particles were created owing to the plastic flow activated by the surface tension of particle soon after primary particles were rearranged so as to have high coordination number. It was shown that their size was determined by the surface tension of the material and temperature used.
(5) It was clarified that the sinterable BeO powder was composed of very small particles which were nearly spherical and so easy to rearrange each other.

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An idea is proposed to synthesize SiC single crystals which don't include carbon particles. In the idea, empty graphite crucible and the crucible holding Si melts are connected by a graphite pipe. The former crucible is heated at about 2500°C like ordinal sublimation method and the temperature of latter crucible is lowered. Crystals are obtained in the empty crucible. Some crystals were obtained based on the idea, but they are not satisfactory yet. Actual problems to realize the idea are discussed mainly in this paper with the results of experiments and from auther's experiences. They are such problems as breaking down of graphite crucible holding molten Si, leakage of Si out of the crucible and the way to control the amounts of Si supplying from Si melts to growth cavity. Some notes are also written on the furnace construction which prefer to the method.

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