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83 巻, 953 号
選択された号の論文の11件中1～11を表示しています
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猪股 吉三1975 年 83 巻 953 号 p. 9-11
発行日: 1975/01/01
公開日: 2010/04/30
ジャーナル フリー熔融シリコンと窒化珪素とのぬれ, および窒化珪素反応焼結体表面にシリコンを含浸させた層を形成させ耐酸化性を向上させることを検討した. 多孔質の窒化珪素反応焼結体上にシリコンの小塊をのせ, 1気圧の窒素雰囲気下で1430-1450℃に10-15分加熱することにより40-100μmの厚さを有するシリコン含浸層が, 焼結体表面に形成される. この含浸層は, 1400℃までの湿空中での酸化に対して優れた耐性を示す. 熔融シリコンと窒化珪素とのぬれに関しても, 酸素分圧との関連で簡単に議論した.抄録全体を表示PDF形式でダウンロード (1515K) -
鈴木 弘茂, 井関 孝善, 長谷 貞三1975 年 83 巻 953 号 p. 12-16
発行日: 1975/01/01
公開日: 2010/04/30
ジャーナル フリーThe distribution of boron contained in small quantities in sea-water and natural magnesia clinkers was determined by α-particle tracks that resulted from 10B(n, α)7Li reaction. Cellulose nitrate film was pressed onto the polished surface of specimens which had been moistened with amyl acetate, then the specimens were irradiated in thermal neutron flux to 1014n/cm2. After the irradiation, the α-track image was developed in the film by etching the film surface. Comparing with α-track analysis, electron probe microanalysis was made on the same position of the same specimen.
As for the sea-water magnesia containing 0.26wt% B2O3 and having the CaO/SiO2 ratio of 0.46, it was found that boron existed around periclase grains together with calcium in a form of matrix. As for the specimens having the C/S ratio of more than 2.5, boron was also distributed at grain boundary, but it was not confirmed owing to background whether boron existed in periclase grain.抄録全体を表示PDF形式でダウンロード (2789K) -
加藤 修三, 伊賀 武雄, 皿井 博美1975 年 83 巻 953 号 p. 17-20
発行日: 1975/01/01
公開日: 2010/04/30
ジャーナル フリーAn apparent activation energy for the rearrangement process in the initial stage of sintering was determined in the temperature range from 1400° to 1600°C on vapor phase decomposed alumina.
The slopes of log-log plots for the shrinkage of this alumina were unity. From this result it was concluded that the rearrangement process occurred in the early stage of sintering. The apparent activation energy for the process was 45kcal/mol. This value was far lower than that obtained for various diffusion processes.抄録全体を表示PDF形式でダウンロード (638K) -
西川 友三, 西田 俊彦, 井上 清1975 年 83 巻 953 号 p. 21-25
発行日: 1975/01/01
公開日: 2010/04/30
ジャーナル フリーIn the temperature range of 1500-1600°C, polycrystalline β-alumina showed brittle fracture in appearance. However, the slip bands in some grains and the cavity-type fracture of the grain boundary showed that plastic deformation occurred even in the temperature range. At 1600-1700°C, the number of the grain disclosing slip band increased, and the deformation of the grains themselves in the polycrystal was also observed. Above 1700°C, especially 1800°C, the ductile deformation of polycrystalline β-alumina was possible without grain boundary fracture. The grains, in the temperature range, deformed easily by the slip resulting from the dislocation movement on c-plane accompanying the grain boundary slip, and the grain-shape changed to the elongated one. This deformation gave a possibility making the polycrystalline β-alumina in which c-plane of the grains orientated perpendicularly to the press forging direction.抄録全体を表示PDF形式でダウンロード (3252K) -
林 国郎, 福井 雅男, 上井 勲1975 年 83 巻 953 号 p. 26-30
発行日: 1975/01/01
公開日: 2010/04/30
ジャーナル フリーThe thermal conductivity of refractory bricks with a high thermal conductivity was measured by the hot wire method. So far a sufficiently large specimen was used, a linear relation was obtained between the heat source temperature (θ) and the logarithm of time (logt) for high conductive materials such as a dense magnesia brick. The thermal conductivity values which were obtained from the linear relation were accurate within ±4% from the mean value.
However, the length of the linear portion in θ-logt plot decreased with decreasing specimen size, and it gave a large error in the result. That is, it became more than ±17% when a cylindrical specimen of a diameter about 70mm was used.
By adjusting the nonlinear portion in θ-logt at the beginning of the measurement with the time t0 which was obtained by ∂t/∂θ-t plot, the length of the linear portion could be made longer and the error was decreased below the permitted limit in the practical measurement.
With application of this adjustment, thermal conductivities of magnesia, carbon and silicon carbide bricks were measured up to 1200°C. The thermal conductivities of these bricks decreased as the temperature rises.抄録全体を表示PDF形式でダウンロード (837K) -
武内 治紀, 永野 正光, 陶山 容子, 加藤 昭夫1975 年 83 巻 953 号 p. 31-35
発行日: 1975/01/01
公開日: 2010/04/30
ジャーナル フリーThe preparation of finely-divided alumina by vapor phase reaction between aluminum tribromide and oxygen was investigated at 950° to 1200°C, with an emphasis on the effects of the reaction conditions on the particle size distribution of the products. The results were as follows:
1) The reaction products were amorphous at 950°C and were δ- or γ-Al2O3 at 1100° and 1200°C. Products were spherical and non-porous particles with the diameter of 350 to 3000Å. The particle size decreased with the increase in temperature and with the decrease of [AlBr3]. When [AlBr3]≅4.5%, the particle size increased with the increase of [O2]. When [AlBr3]≅1%, the particle size was minimum at about [O2]=32%. By controlling these three factors, ultrafine alumina powders with a controlled particle-size distribution were prepared by the vapor phase oxygenolysis of aluminum trihalides.
2) In contrast with AlCl3-O2 system, alumina powders obtained from AlBr3-O2 system. The concentration of oxygen influenced Predominantly on the bromine content which was 7-16wt% at [O2]≥32% and was less than 2.5wt% at [O2]<8%. A heat treatment above 1100°C was required to remove bromine.抄録全体を表示PDF形式でダウンロード (1675K) -
進藤 勇, 鈴木 弘茂1975 年 83 巻 953 号 p. 36-40
発行日: 1975/01/01
公開日: 2010/04/30
ジャーナル フリー酸化ベリリウムのNaOH溶液中における水熱溶解度を測定し, その溶解機構を明らかにすると共に, 溶解の活性化エネルギーを算出した. 酸化ベリリウムのNaOH溶液中への溶解反応は単一ではなく, 約350℃付近より低温側では次の (1) 式に, 400℃付近以上では (2) 式に従っているものと推論された.
(1) BeO+3(OH)-=BeO2(OH)3-+H2O
(2) BeO+2(OH)-=BeO22-+H2O
(1) 式から (2) 式への転移温度は, NaOH溶液の濃度が高くなるにつれて, 高温側にずれて行く.
一方, これら2つの溶解反応に対して, それぞれVan't Hoffの式が成立し, これから溶解の活性化エネルギーは (1) 式に対しては2.7±0.1kcal/mol, (2) 式に対しては5.0±0.1kcal/molと計算された.抄録全体を表示PDF形式でダウンロード (641K) -
高橋 順一, 小平 紘平, 松下 徹, 山井 巌, 斎藤 肇1975 年 83 巻 953 号 p. 41-45
発行日: 1975/01/01
公開日: 2010/04/30
ジャーナル フリーThe effect of V2O5 additive on the sintering of SnO2 was studied by measuring relative density and isothermal shrinkage in the temperature range 800 to 1400°C. The optimum amount of V2O5 added was 10wt%, which might be the solid solubility limit of vanadium ion into SnO2 lattice. With this amount of V2O5, the shrinkage behavior agreed with a model based on liquid-phase sintering at lower temperature. At higher temperature above 1250°C, the major parts of the densification occurred very rapidly and was followed by a much slower sintering process typical of volume diffussion. The fast early shrinkage might be caused by the capillary forces of liquid and the rapid formation of solid solution.
Grain growth followed the expression G3-G03=At with an apparent activation energy of 104kcal/mol. The volume diffusion of oxygen ion was rate determining step for grain growth in this experiment.抄録全体を表示PDF形式でダウンロード (768K) -
中村 専一, 林 宏1975 年 83 巻 953 号 p. 46-53
発行日: 1975/01/01
公開日: 2010/04/30
ジャーナル フリーSome compounds in the ternary system Li2O-B2O3-H2O were synthesized, e.g. LBH16 (L: Li2O, B: B2O3, H: H2O), LBH4, LB2H3, LB5H10 etc. Each compound was confirmed to be single phase by means of chemical analysis, DTA, TGA and X-ray diffraction.
The compound LBH16 is hexagonal with the lattice parameter a0=5.70 and c0=6.20Å. The diffraction data of “LBH16” (Powder Diffraction File No. 16-286) did not coincide with those of the synthesized LBH16, and should be attributed to LBH4 contaminated with a small amounts of LB2H3. The diffraction data of synthesized LBH4 were not consistent with those of “LBH4” (File No. 16-312), and practically agreed with those of LBH4 reported by Sastry and Hummel [J. Am. Ceram. Soc. 41, 7 (1958)].
Instead of “LBH” (File No. 16-198), LBHx with variable x smaller than 1 was obtained through dehydration of LBH4. The crystal structure of this compound is considered to remain unchanged within a certain range of water content.
The diffraction data of the synthesized LB2H3 agreed approximately with those of “LB2H4” (File No. 16-313) and “LB2H5” (File No. 1-0112), and those of LB2H3 reported Bouaziz [Bull. Soc. Chem. (France) 2, 1451 (1962)] were in rough agreement with the data of LB2Hx which was obtained in the course of dehydration process of the synthesized LB2H3.抄録全体を表示PDF形式でダウンロード (1148K) -
木島 弌倫1975 年 83 巻 953 号 p. 54-55
発行日: 1975/01/01
公開日: 2010/04/30
ジャーナル フリーPDF形式でダウンロード (938K) -
1975 年 83 巻 953 号 p. A1-A10
発行日: 1975/01/01
公開日: 2010/04/30
ジャーナル フリーPDF形式でダウンロード (2244K)
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