Pub Date : 1976-01-01DOI: 10.2109/JCERSJ1950.84.973_444
T. Sasamoto, H. Hara, T. Sata
{"title":"Change in impurity contents in magnesia after vaporization in vacuum.","authors":"T. Sasamoto, H. Hara, T. Sata","doi":"10.2109/JCERSJ1950.84.973_444","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.84.973_444","url":null,"abstract":"","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1976-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85523297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1976-01-01DOI: 10.2109/JCERSJ1950.84.971_348
Y. Moriyoshi, W. Komatsu
In the previous paper1), a kinetic equation for the initial combined sintering of surface and volume diffusions was developed. The result is shown in Eq. (1), (ƒ¢L/L0)712/(t-ƒÂt)=K(ƒ¢L/L0)+H•c•c(1) and the second term of the right side of Eq. (1) gives the surface diffusion coefficient Ds as shown in Eq. (2). Ds=(4kTm7/7ƒÂƒÁƒ¶)Ha4•c•c(2) Eq. (2) shows that the surface diffusion coefficient strongly depends on particles size. In the previous work no effort, however, was made for obtaining powder with narrow size distribution. The intention of the present work is to supplement the previous work and to show experimentally the effect of particle size distribution on the value of Ds. High purity ƒÁ-Al2O3 (99.99%) for the synthesis of a single crystal purchased from Shinkosha was fired at 1200•Ž for 50h and completely converted to ƒ¿-Al2O3 of nearly spherical form. The resulting particle was repeatedly elutriated in water containing 4vol% of NH4OH. The sample obtained had the narrow distribution of 0.2•`0.4ƒÊ in diameter, while the previous one the wide distribution giving the average size of 0.2ƒÊ The powder was hand pressed into a compact (10mm in diameter and about 4mm thick) at 1t/cm2 without binder. The
{"title":"Surface diffusion in the initial sintering of alumina.","authors":"Y. Moriyoshi, W. Komatsu","doi":"10.2109/JCERSJ1950.84.971_348","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.84.971_348","url":null,"abstract":"In the previous paper1), a kinetic equation for the initial combined sintering of surface and volume diffusions was developed. The result is shown in Eq. (1), (ƒ¢L/L0)712/(t-ƒÂt)=K(ƒ¢L/L0)+H•c•c(1) and the second term of the right side of Eq. (1) gives the surface diffusion coefficient Ds as shown in Eq. (2). Ds=(4kTm7/7ƒÂƒÁƒ¶)Ha4•c•c(2) Eq. (2) shows that the surface diffusion coefficient strongly depends on particles size. In the previous work no effort, however, was made for obtaining powder with narrow size distribution. The intention of the present work is to supplement the previous work and to show experimentally the effect of particle size distribution on the value of Ds. High purity ƒÁ-Al2O3 (99.99%) for the synthesis of a single crystal purchased from Shinkosha was fired at 1200•Ž for 50h and completely converted to ƒ¿-Al2O3 of nearly spherical form. The resulting particle was repeatedly elutriated in water containing 4vol% of NH4OH. The sample obtained had the narrow distribution of 0.2•`0.4ƒÊ in diameter, while the previous one the wide distribution giving the average size of 0.2ƒÊ The powder was hand pressed into a compact (10mm in diameter and about 4mm thick) at 1t/cm2 without binder. The","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1976-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84371712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1975-11-01DOI: 10.2109/JCERSJ1950.83.963_528
武 星川, 三郎 赤木
The glasses of SiO2-Fe2O3-K2O system were heat-treated at 800°C-1100°C, and the inversion temperature and the lattice constants of Fe-leucite crystals precipitated in the glass were measured by using DTA apparatus and X-ray diffractometer.It was found that the change of inversion temperature was closely related with the atomic ratio δ=Si/(Si+Fe+K) of the mother glass composition. Each Fe-leucite crystal precipitated in the glasses with δ 0.5 lowered with the increase of δ. The lower crystallization temperature was, the more steep the degree of lowering was. It was also observed that there is a linear relationship between the inversion temperature and the lattice parameter c/a, when δ>0.5.It was considered that in the case of δ>0.5, Fe-leucite crystal having the composition of (KFe)1-xSi2+xO6(x>0) had a higher symmetrical lattice than the ideal one and the lattice defects which might be caused by the defficiencies of K+ increasing with δ.The influence of other phases such as residual glass, hexagonal KFeSiO4 crystals and hematite crystals on the inversion temperature was not observed.
{"title":"SiO2-Fe2O3-K2O系ガラスから生成したFe-leucite結晶の転移温度","authors":"武 星川, 三郎 赤木","doi":"10.2109/JCERSJ1950.83.963_528","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.83.963_528","url":null,"abstract":"The glasses of SiO2-Fe2O3-K2O system were heat-treated at 800°C-1100°C, and the inversion temperature and the lattice constants of Fe-leucite crystals precipitated in the glass were measured by using DTA apparatus and X-ray diffractometer.It was found that the change of inversion temperature was closely related with the atomic ratio δ=Si/(Si+Fe+K) of the mother glass composition. Each Fe-leucite crystal precipitated in the glasses with δ 0.5 lowered with the increase of δ. The lower crystallization temperature was, the more steep the degree of lowering was. It was also observed that there is a linear relationship between the inversion temperature and the lattice parameter c/a, when δ>0.5.It was considered that in the case of δ>0.5, Fe-leucite crystal having the composition of (KFe)1-xSi2+xO6(x>0) had a higher symmetrical lattice than the ideal one and the lattice defects which might be caused by the defficiencies of K+ increasing with δ.The influence of other phases such as residual glass, hexagonal KFeSiO4 crystals and hematite crystals on the inversion temperature was not observed.","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1975-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88804144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1975-01-01DOI: 10.2109/JCERSJ1950.83.961_471
Masayuki Shiozawa, K. Narita, Y. Fujita, Satoru Kurita, M. Takata, H. Yanagida
{"title":"Application of sintered bodies of TiO2 doped with Nb2O5 to anodic photooxidation of water.","authors":"Masayuki Shiozawa, K. Narita, Y. Fujita, Satoru Kurita, M. Takata, H. Yanagida","doi":"10.2109/JCERSJ1950.83.961_471","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.83.961_471","url":null,"abstract":"","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1975-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77180983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1975-01-01DOI: 10.2109/JCERSJ1950.83.17
Shuzo Kato, T. Iga, Hiromi Sarai
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.
{"title":"Rearrangement Process in the Initial Stage Sintering of Vapor Phase Decomposed Alumina","authors":"Shuzo Kato, T. Iga, Hiromi Sarai","doi":"10.2109/JCERSJ1950.83.17","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.83.17","url":null,"abstract":"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.","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1975-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80679239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1974-11-01DOI: 10.2109/JCERSJ1950.82.951_587
章彦 柘植, 寛和 井上, 勝利 米屋
1) A mutual solubility of titanium nitride and cobalt was observed in the sintering of the TiN-Co system at 1600°-1800°C.2) In the sintering of the TiN-WC-Co system, in addition to the above fact, tungsten carbide seemed to be dissolved into the other two phases, in the way that W atoms were mainly dissolved into the cobalt phase whereas C atoms were dissolved into the titanium nitride phase.3) The microstructure of TiN-10wt% WC-20wt% Co alloy was analysed by E. P. M. A. and I. M. A.. Grains were titanium nitride phase and a binder phase was cobalt phase.4) The solid skelton forming for grains during sintering for the binary systems was observed and it is indicating the incomplete wetting of tungsten carbide to this binary alloy resulted in an improvement of the wettability of titanium nitride phase to the binder phase.5) The solution-precipitation process in the sintering for the TiN-WC-Co system was controlled by the solution reaction of granular particles at solid-liquid boundaries.6) The maximum mechanical strength obtained for the TiN-WC-Co ternary alloys at any sintering conditions was essentially higher than that for the TiN-Co binary alloys.
1)的相互溶解性氮化钛和钴烧结TiN-Co系统中可观察到1600°-1800°C.2)的烧结TiN-WC-Co系统,除了上面的事实,似乎碳化钨溶解到其他两个阶段,在W原子的方式主要是溶解进入钴相而C原子被溶解到氮化钛phase.3) TiN-10wt % WC-20wt %公司合金的微观结构分析了e . p . m . A .和i . m . . .4)二元体系烧结过程中晶粒的固骨架形成，说明碳化钨对二元合金的不完全润湿导致了氮化钛对黏结相的润湿性提高。5)TiN-WC-Co体系烧结过程中的固-析出过程受颗粒在固-液中的溶解反应控制6) TiN-WC-Co三元合金在任何烧结条件下获得的最大机械强度基本上都高于TiN-Co二元合金。
{"title":"TiN-CoおよびTiN-WC-Co系の液相焼結","authors":"章彦 柘植, 寛和 井上, 勝利 米屋","doi":"10.2109/JCERSJ1950.82.951_587","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.82.951_587","url":null,"abstract":"1) A mutual solubility of titanium nitride and cobalt was observed in the sintering of the TiN-Co system at 1600°-1800°C.2) In the sintering of the TiN-WC-Co system, in addition to the above fact, tungsten carbide seemed to be dissolved into the other two phases, in the way that W atoms were mainly dissolved into the cobalt phase whereas C atoms were dissolved into the titanium nitride phase.3) The microstructure of TiN-10wt% WC-20wt% Co alloy was analysed by E. P. M. A. and I. M. A.. Grains were titanium nitride phase and a binder phase was cobalt phase.4) The solid skelton forming for grains during sintering for the binary systems was observed and it is indicating the incomplete wetting of tungsten carbide to this binary alloy resulted in an improvement of the wettability of titanium nitride phase to the binder phase.5) The solution-precipitation process in the sintering for the TiN-WC-Co system was controlled by the solution reaction of granular particles at solid-liquid boundaries.6) The maximum mechanical strength obtained for the TiN-WC-Co ternary alloys at any sintering conditions was essentially higher than that for the TiN-Co binary alloys.","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1974-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84375698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1974-01-01DOI: 10.2109/JCERSJ1950.82.48
隆 杉村, 斉 大里, 雄吉 中井
It was found that an indialite-like crystal was precipitated on heat treatment of some glasses of the compositions near 2ZnO⋅2Al2O3⋅5SiO2. The formation and the thermal stability of this phase and some characters of the crystallized glasses containing this phase were examined and the following results were obtained.1) Zn-indialite (2ZnO⋅2Al2O3⋅5SiO2) was precipitated as a main phase when glasses of the compositions 2.17ZnO⋅2Al2O3⋅4.77SiO2, 2.16ZnO⋅2Al2O3⋅5SiO2, for example, were heated at 870°-1000°C.2) Zn-indialite was metastable, converting easily to a mixture of gahnite and silica above 1000°C.3) Long crystals (500μ) were formed at the block surface, perpendicular to it, when glass block was heated.4) The Zn-indialite precipitated in glasses was hexagonal or pseudohexagonal and in many cases optically uniaxial negative, having unit cell lengths a and c equaling 9.82A and 9.35A, respectively.5) The coefficient of thermal expansion of the Zn-indialite aggregate was 11×10-7/c, similar to that of indialite.
{"title":"ZnO-Al2O3-SiO2系ガラスから析出する準安定Indialite","authors":"隆 杉村, 斉 大里, 雄吉 中井","doi":"10.2109/JCERSJ1950.82.48","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.82.48","url":null,"abstract":"It was found that an indialite-like crystal was precipitated on heat treatment of some glasses of the compositions near 2ZnO⋅2Al2O3⋅5SiO2. The formation and the thermal stability of this phase and some characters of the crystallized glasses containing this phase were examined and the following results were obtained.1) Zn-indialite (2ZnO⋅2Al2O3⋅5SiO2) was precipitated as a main phase when glasses of the compositions 2.17ZnO⋅2Al2O3⋅4.77SiO2, 2.16ZnO⋅2Al2O3⋅5SiO2, for example, were heated at 870°-1000°C.2) Zn-indialite was metastable, converting easily to a mixture of gahnite and silica above 1000°C.3) Long crystals (500μ) were formed at the block surface, perpendicular to it, when glass block was heated.4) The Zn-indialite precipitated in glasses was hexagonal or pseudohexagonal and in many cases optically uniaxial negative, having unit cell lengths a and c equaling 9.82A and 9.35A, respectively.5) The coefficient of thermal expansion of the Zn-indialite aggregate was 11×10-7/c, similar to that of indialite.","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1974-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81459747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1974-01-01DOI: 10.2109/JCERSJ1950.82.951_603
T. Sasamoto, Hong-lim Lee, T. Sata
{"title":"Effects of porosity on vacuum-vaporization of magnesia.","authors":"T. Sasamoto, Hong-lim Lee, T. Sata","doi":"10.2109/JCERSJ1950.82.951_603","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.82.951_603","url":null,"abstract":"","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1974-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73034392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1974-01-01DOI: 10.2109/JCERSJ1950.82.950_564
R. Ota, M. Kunugi
Glasses in the system As-Se were heat-treated at temperatures higher than Tg (glass transition temperature) for 20-340 hours in order to study the relation between the crystalline phase formed in a glass and the structure of the glass.The crystalline phases formed during the thermal treatment were identified by X-ray diffraction technique as hexagonal Se in the case of Se glass and As2Se3 in the case of As2Se3 and AsSe glasses.The crystallization of Se glass, which was initiated by homogeneous nucleation, was determined by density change, but heterogeneous crystallization was observed in As2Se3 glass and the crystal growth was measured by means of metallurgical microscopy as functions of temperature and time.The activation energies for nucleation (EN) and for crystal growth (EG) calculated from the Arrhenius plots of the induction periods of crystallization and the growth rate G are as follows; EN=29.4±0.8kcal/mole and EG=12.6±2.2kcal/mole for Se glass, and EN=41.2kcal/mole and EG=26.7kcal/mole for As2Se3 glass. They turned out to be much smaller than the activation energy for viscous flow at constant pressure or than the cleavage energy of a single bond such as Se-Se bond (44kcal/mole) or As-Se bond (42kcal/mole.).
{"title":"Heat Treatment and Crystallization of Glasses in the System As-Se","authors":"R. Ota, M. Kunugi","doi":"10.2109/JCERSJ1950.82.950_564","DOIUrl":"https://doi.org/10.2109/JCERSJ1950.82.950_564","url":null,"abstract":"Glasses in the system As-Se were heat-treated at temperatures higher than Tg (glass transition temperature) for 20-340 hours in order to study the relation between the crystalline phase formed in a glass and the structure of the glass.The crystalline phases formed during the thermal treatment were identified by X-ray diffraction technique as hexagonal Se in the case of Se glass and As2Se3 in the case of As2Se3 and AsSe glasses.The crystallization of Se glass, which was initiated by homogeneous nucleation, was determined by density change, but heterogeneous crystallization was observed in As2Se3 glass and the crystal growth was measured by means of metallurgical microscopy as functions of temperature and time.The activation energies for nucleation (EN) and for crystal growth (EG) calculated from the Arrhenius plots of the induction periods of crystallization and the growth rate G are as follows; EN=29.4±0.8kcal/mole and EG=12.6±2.2kcal/mole for Se glass, and EN=41.2kcal/mole and EG=26.7kcal/mole for As2Se3 glass. They turned out to be much smaller than the activation energy for viscous flow at constant pressure or than the cleavage energy of a single bond such as Se-Se bond (44kcal/mole) or As-Se bond (42kcal/mole.).","PeriodicalId":17274,"journal":{"name":"Journal of the Ceramic Association, Japan","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1974-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79935423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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