タングステンブロンズ型Ba₂Na_1-xLi_xNb₅O₁₅系化合物の二, 三の組成 (x=0, 0.2, 0.4) について, 熔融法で結晶育成を試みた. 特にx=0.2の組成では (001) 面を自然面に持つ一辺10-20mmの透明結晶が得られた. 室温 (25℃) での格子常数はそれぞれa₀=17.473Å, b₀=17.480Å, c₀=9.503Åであった. Curie点は490℃に存在し, 室温での誘電率はそれぞれε₃₃^T=60, ε₁₁^T=180を示し, Curie点でのそれはε₃₃^T=1500, ε₁₁^T=360であった. 50HzのSowyer-Tower回路から求めた室温での残留分極値P_r3=2.3μC/cm², 抗電力E_c3=1400V/mmであった. 105℃ではP_r3=21μC/cm², E_c3=640V/mmを示した. 偏光顕微鏡下での強誘電的180°分域の観察を行い, あわせて, エッチングピットの観察から分域の正端および負端の関係について検討を加えた. また化学分析を行い, 化合物の充填組成量と結晶組成量との関係についても検討を試みた.

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珪酸三石灰 (C₃S) と水との混合直後の反応は3つの内容をもち, i) 粒子表面からC₃Sが水にcongruentに溶解し, 水溶液はC-S-Hに関して過飽和となってC-S-H (I) を沈殿する, ii) 溶解後C₃S粒子表面に3-4分子層の水分子が吸着して表面を準安定化する. この時の吸着熱は530±40erg/cm₂, iii) C₃S 粒子表面に局所的にC-S-H (II) の核を生成する. 純水の代りに石灰飽和液を用いるとi) の反応は無視できる.
その後の “Dormant Period” (誘導期間) 中は, C-S-H (II) の結晶成長が主反応で, この期間の反応率-時間関係は, 水和熱測定, 液相中のCa²⁺とシリケートイオン濃度の分析および固相の結合水定量結果から, 式 (10) で表わされた. 誘導期間は, 液相のCa²⁺イオン濃度がCa(OH)₂に関する飽和比約2の最大過飽和に到達する時に終わり, 水和反応は急速に進行するようになる. その引金は, C-S-H (II) の成長反応に伴って溶解するCa(OH)₂が直ちに, C₃S粒子の露出された表面に析出し, 新しいC-S-H (II) の核生成を誘発することにあり, このC-S-H (II) の核生成-成長が増殖的に進むと見なすと, 硬化初期段階までの反応量-時間関係は式 (15) によって表現される.

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ペロブスカイト構造を有する化合物は誘電性や磁性などの面から注目され, 数多くの複合ペロブスカイト酸化物が合成されてきた. しかしCr³⁺イオンを含むその複酸化物の合成例は少ない. Sr(Cr_2/1Nb_1/2)O₃やCa(Cr_1/2Nb_1/2)O₃は複合ペロブスカイト酸化物として知られているが, そのAイオンをPbやBaとする場合にはクロム酸塩を生成するためにその複合ペロブスカイト酸化物の生成は実現されていない. そこでA²⁺(Cr_1/2Nb_1/2)O₃(A=Pb, Ba) を不活性ガス中で反応させた. その結果, Pb(Cr_1/2Nb_1/2)O₃は立方晶のペロブスカイト化合物であり, Ba(Cr_1/2Nb_1/2)O₃は2つの多体を持つ六方晶ペロブスカイト類似化合物であった. 後者の場合, 合成温度が低い時に生成する六方晶は6枚周期 (hexagonal BaTiO3) 構造を示し, 合成温度が高い時に生成する六方晶は8枚周期構造を示した. この8枚周期構造におけるBaO₃層の積み重り方は立方最密充填と六方最密充填とが3:1の比率の組合せによって構成されており, 8枚周期構造は6枚周期構造とペロブスカイト構造との中間に類するものであった. 更に高圧下の加熱処理によって, 立方晶のペロブスカイト酸化物Ba(Cr_1/2Nb_1/2)O₃が生成した. このように異なる反応条件によって得られたBa(Cr_1/2Nb_1/2)O₃のX線密度はペロブスカイト構造 (d_x=6.56), 8枚周期構造 (d_x=6.39), 6枚周期構造 (d_x=6.34) の順で減少した. それはその六方格子が (110) 面上に位置するBイオン間の反発力によってc軸方向に伸び, その体積が増大するからである. Cr³⁺イオンを含むBa化合物が六方晶ペロブスカイト類似構造をとる傾向はCr³⁺イオンがe_g軌道にd電子を持たないために短かい距離で直接に向きあっているCr³⁺イオン同志の反発力が比較的弱いためであると考えられる.

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The relation between the solubility of Pb atom by 4% acetic acid treatment and the change of infra-red reflection spectrum in the system PbO-SiO₂ frit containing various cation was studied. The infra-red reflection spectrum of frits treated by acetic acid changed as compared with that untreated sample and the degree of the change increased with the increase of the amount of dissolved Pb atom.
The results obtained were as follows.
1) The peak of 1090cm^-1 due to Si-O-Si bond existing the surface of frit caused by the treatment with acetic acid was observed. The intensity of the peak increased with the increase of dissolved Pb atom, but no peak shifted.
2) When the amount of dissolved Pb atom was comparatively large, the peak intensity of 950cm^-1 due to Si-O-Pb bond was smaller than that of 1090cm^-1. In the case that the amount of dissolved Pb atom was comparatively small, it was opposite direction.
3) When the amount of dissolved Pb atom was very large, the peaks of 1050cm^-1 due to Si-O- or Si-O…H bond and 1200cm^-1 due to Si-O-Si bond in the spectrum were observed. The former was shifted to lower wave number and the latter to higher wave number with the increase of dissolved Pb atom.

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The formation processes of CaO⋅Al₂O₃ (CA) from the mixtures of C₃A, C₁₂A₇ and CaCO₃ with α-Al₂O₃ were investigated kinetically on heating at 900°-1200°C in air, in dry- and wet- nitrogen atmospheres. The results obtained were,
(1) Oo the formation of CA from C₃A and α-Al₂O₃, the crystalline phase C₁₂A₇ was found and its amount had a maximum at the early stage of the reaction.
(2) On the formation of CA from C₁₂A₇ and α-Al₂O₃, no crystalline phase was found except CA.
(3) On the formation of CA from CaCO₃ and α-Al₂O₃, C₃A and C₁₂A₇ were formed at the early period of burning and the rate of CA formation was slower than those from the mixtures of C₁₂A₇ and C₃A with α-Al₂O₃. At 1200°C, C₃A was detected only at the beginning of the reaction showing a maximum at a short time of heating. The amount of C₁₂A₇ showed also a maximum, similar to the case of (1).
From the experimental data obtained, the formation process of CA from C₃A and α-Al₂O₃ was explained to be a consecutive one through C₁₂A₇, that is,
C₃A+3/4α-Al₂O₃→1/4C₁₂A₇+5/4α-Al₂O₃→3CA
On the formation of CA from CaCO₃ and α-Al₂O₃, a similar consecutive process might be assumed.
In the presence of water in atmosphere, the over-all rate of formation of CA became larger, as the formation of C₁₂A₇ was accelerated by water.

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Nitridation kinetics between silicon powder (purity>99.999%, average grain size: ca. 2μ) and nitrogen was studied experimentally, and it was shown that the reaction followed linear rate law. The activation energy of the reaction was calculated as 158kcal/mol and the reaction rate was nearly proportional to the square root of grain size.
From those facts, the activation energy is considered to correspond with a barrier of diffusion process of nitrogen atom through thin nitride skin built on the silicon particles, and the reaction is accounted to proceed repeating crack formation or exfoliation of the surface skin. The surface skin seems to become unstable at the thickness, 300-500Å in the range of temperature, 1200-1400°C.

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This study describes a method used for the fabrication of the bicrystals of magnesium oxide by joining two single crystals.
Polished two crystals with {100} cleavage plane to be joining into a bicrystal were packed in highly pure magnesia powders to avoid the vaporization.
Then, the bicrystals of magnesium oxide have been successfully formed under 300g/cm² for 40 minutes at 2400°C in a graphite resistance furnace under one atmosphere of highly pure argon.
The resulting grain boundary was microscopically invisible, free of void and optically transparent. Also the boundary was scarcely sign of chemical attack, and no particular deviation was observed on the results of microhardness test.
This suggests that the bicrystal formed here has fairly intimate bonding at the boundary together with the crystals.

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Demand for artificial light weight aggregate has been increasing rapidly. Consequently, it has been revealed the shortage of bloatable raw material or the difficulty of transportation due to longer distance to the consumption district. In order to give a solution for these problems, a study was made to improve the bloating property of Hayama shale which is abundantly deposited in Miura Penisula district, Kanagawa Prefecture, but is less bloatable.
Initially, the Hayama-shale was subjected to chemical and mineral analyses and also was measured the pore distribution and the specific gravity. Comparison of these data with that of bloatable shale found an outstanding difference in the porosity inherent to the younger geological period.
A series of experiment was carried out to find the most practical method to improve the bloating properties which were found to be strongly dependent on the porous structure of the raw material, and indicated that the sufficient property would be obtained by applying a extruding pelletizer to press it untill the specific gravity being more than 1.7.
Based on the result, a flow sheet of the manufacturing plant to produce artificial light weight aggregate was described and engineering data to design the practical pelletizer and kiln were obtained by operating test plants.

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