巻号一覧
1990 巻 (1990)
- 229 号 p. 387-
- 228 号 p. 255-
- 227 号 p. 195-
- 226 号 p. 127-
- 225 号 p. 63-
- 224 号 p. 3-
前身誌
1990 巻, 226 号
選択された号の論文の8件中1～8を表示しています
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豊倉 賢, 赤石 信一, 佐瀬 潔1990 年 1990 巻 226 号 p. 127-134
発行日: 1990/05/01
公開日: 2011/03/07
ジャーナル フリーNeedle calcium sulfate dihydrate crystals were added into a supersaturated solution obtained from reaction between two aquous solutions of calcium chloride and ammonium sulfate, and were suspended by agitation. Size distributions of suspended crystals were observed every one or two hours.
The average size of latitudinal length of large crystals increased with operating period. From the data the rate of increase of the average size was calculated and was correlated with the supersaturation. But the size distribution of longitudinal length was scarcely changed through these operations of 9 hours. The total number of suspended large seed crystals was constant through operating period, but many fine crystals came out. The average size of the fine crystals suspended with large crystals increased or decreased with operational period. Then within the operational conditions of these tests, needle crystals suspended in a solution were considered to be broken on the edge of them.
On the other hands, the average size of latitudinal and longitudinal length of fine crystals without large crystals, increased until critical size of breakage.抄録全体を表示PDF形式でダウンロード (1544K) -
三五 弘之, 宮川 継男, 笠井 順一1990 年 1990 巻 226 号 p. 135-142
発行日: 1990/05/01
公開日: 2011/03/07
ジャーナル フリーIt was expected that the high-temperature stability, that is therm ostability, of 12CaO·7Al2O3 solid solution depended on the anions substituted in its crystal structure. The chemical formula of 12CaO·7Al2O3 solid solution corresponds to 11CaO·7Al2O3·CaX2, where X is hydroxyl group or halogen. In the present report, we compared the system 12CaO·7Al2O3-CaSO4 with the system 12CaO·7Al2O3.CaF2-CaSO4 and discussed the effect of CaSO4·H2O on the thermostability of 12CaO·7Al2O3 solid solution.
Before burning, 12CaO·7Al2O3 or 11CaO·7Al2O3·CaF2 was well mixed together with CaSO4·2H2O. Burned products were examined by X-ray powder diffraction with a Geiger counter diffractometer. Some of the samples were also analyzed chemically for total F, SO3 and free CaO.
It was confirmed that 4CaO·3Al2O3. SO3 was formed by reaction between 12CaO·7Al2O3 or 11CaO·7Al2O3·CaF2 and CaSO4. It appeared at 1000°C in the former system and at 1100°C in the latter system. These suggested that 11CaO·7Al2O3.CaF2 was more thermostable than 12CaO·7Al2O3 in the presence of CaSO4. After the fluorination, 11CaO·7Al2O3·CaF2 reacted with CaSO4 to form 4CaO·3Al2O3·SO3. Subsequently as the burning temperature was raised, 4CaO·3Al2O3. SO3 was decomposed with liberation of SO3 and to form calcium aluminates based on the system CaO-Al2O3. Addition of CaO or CaF2 to 4CaO·3Al2O3-SO3 lowered its decomposition temperature.抄録全体を表示PDF形式でダウンロード (1026K) -
門間 英毅, 高橋 卓二1990 年 1990 巻 226 号 p. 143-147
発行日: 1990/05/01
公開日: 2011/03/07
ジャーナル フリーDense and macroporous apatite ceramics were prepared by using the hydraulicity of tricalcium phosphate (TCP), and their properties were investigated. For the preparation of dense form, powder mixtures of TCP and CaCO3, CaC2O4·H2O or Ca (OH) 2 with the Ca/P molar ratio of stoichiometric apatite (Ca/P=1.67) were compacted, and then the compacts intact or after hydration-treatment were sintered at temperatures ranging from 1000 to 1350°C. The resulting sintered bodies had porosities from 4 to 18%, compressive strengths from 100 to 500MPa, and diametral strengths from 2 to 16MPa. The intermediate hydration-treatment was effective for improving the machineability and sinterability of the powder compacts. For the preparation of macroporous form, water-pastes of mixtures of TCP, CaC2O4·H2O and a large amount of polymer beads were hydrated and hardened, and the hardened bodies were sintered at 1000-1350°C after elimination of the beads at low temperatures. Sintered bodies thus obtained had a typical beads-type macroporous structure in which spherical pores connected mutually with small holes.抄録全体を表示PDF形式でダウンロード (1371K) -
川島 和仁, 菅野 雅史, 町長 治, 笠井 順一1990 年 1990 巻 226 号 p. 149-158
発行日: 1990/05/01
公開日: 2011/03/07
ジャーナル フリーThis paper deals with the Ca [Zn (OH) 3 H2O] 2 synthesis from the system CaO-ZnO-H20 or the system Ca (NO3) 2-CaCl2-NaOH-H2O, indicating that Ca [Zn (OH) 3H2O] 2 is suited for portland cement setting time retarder.
The results obtained are as follows.
(1) If Ca [Zn (OH) 3H2O] 2 synthesis from the system CaO-ZnO-H2O is tried, the Ca [Zn (OH) 3H2O] 2 formation velocity is more accelerated, when the reaction temperature is lower and, at above 60°C, it is not formed.
(2) The Ca [Zn (OH) 3H2O] 2 formation time is accelerated by adding NH4OH into the system CaO-ZnO-H2O.
(3) Ca [Zn (OH) 3H2O] 2 is an aqo coordination compound, Zn coordination number is 4, while that for Ca is 6.
(4) ca [zn (OH)3 H2O] 2 dehydration is accomplished in the following three steps (125°C, 157°C and 380°C).
(5) Ca [Zn (OH)S3 H2O] 2 addition to portland cement retards the setting time for 1-2 hours, but increases the compressive strength over a long period.抄録全体を表示PDF形式でダウンロード (1702K) -
中川 晃次, 寺島 勲, 浅賀 喜与志, 大門 正機1990 年 1990 巻 226 号 p. 159-164
発行日: 1990/05/01
公開日: 2011/03/07
ジャーナル フリーAuthors synthesized amorphous calcium aluminate with the chemical composition of 3CaO·3Al2O3·CaF2. The hydration mechanisms of amorphous 3CaO·3Al2O3·CaF2 and the effect of Ca (OH) 2 and/or CaSO4 on the hydration were investigated by determing loss on ignition of hydrated sample, heat liberation during hydration, relative intensity of X-RD peaks, amounts of formed ettringite, and the hydration percentage of amorphous calcium aluminate. The hydration ratio of amorphous calcium aluminate were measured by salycilic acid-methanol method and ettringite was measured by DSC.
When amorphous 3CaO·3Al2O3·CaF2 was contacted with water, the rapid hydration was occurred. But, the hydration was significantly retarded at later stage. By addition of Ca (OH) 2 and CaSO4, the hydration ratio of amorphous calcium aluminate was increased from early stage to later stage. The retardation might be caused by the protective layers of hydrated amorphous products surrounding unhydrated grains. This densely formed product layer was supposed to convert into crystalline phases such as C2AH8, monosulfate and ettringite by the addition of Ca (OH) 2 and/or CaSO4.抄録全体を表示PDF形式でダウンロード (1375K) -
呉羽 正三, 木村 啓一, 五十嵐 一美, 田中 宏一1990 年 1990 巻 226 号 p. 165-170
発行日: 1990/05/01
公開日: 2011/03/07
ジャーナル フリーPDF形式でダウンロード (1582K) -
斎藤 茂郎, 中村 渉, 石井 覚1990 年 1990 巻 226 号 p. 171-176
発行日: 1990/05/01
公開日: 2011/03/07
ジャーナル フリーPDF形式でダウンロード (1830K) -
構造と特性輿水 仁, 坂本 尚史, 大塚 良平1990 年 1990 巻 226 号 p. 177-184
発行日: 1990/05/01
公開日: 2011/03/07
ジャーナル フリーPDF形式でダウンロード (847K)
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