著者
石堂 善彦 藤井 欽二郎
出版者
公益社団法人 日本セラミックス協会
雑誌
窯業協會誌 (ISSN:00090255)
巻号頁・発行日
vol.81, no.931, pp.115-117, 1973-03-01 (Released:2010-04-30)
参考文献数
5

Fused magnesia and magnesia clinker which were pulverized to such a fineness as shown in Table 1, were proven to react rather readily with glacial acetic acid at a temperature from 20° to 65°C. When the fractions of magnesia reacted were followed at each constant temperature by determining magnesium acetate formed in the reaction mixture which was soluble in methanol, the reactions proceeded after Jander's rate-equation except later reaction-stage as shown in Fig. 1 with an apparent activation energy of 21.8kcal/mol, though any diffusion layer didn't be observed around magnesia grains under microscope. In a semi-adiabatic condition, the temperature of the mixture should rise owing to the heat of reaction, resulting in acceleration of the rate of reaction more and more to cause the mixture to boil. These situations were examined at an initial temperature from 30° to 60°C. The results were shown in Fig. 3 in comparison with those obtained by numerical calculation using the rate data at constant temperatures and heat contents of the matters concerning to the reaction system.
著者
Anupam PURWAR Ragini MUKHERJEE Krishnamurthy RAVIKUMAR S. ARIHARAN Nagarajan Kirupakaran GOPINATH Bikramjit BASU
出版者
公益社団法人 日本セラミックス協会
雑誌
Journal of the Ceramic Society of Japan (ISSN:18820743)
巻号頁・発行日
vol.124, no.4, pp.393-402, 2016-04-01 (Released:2016-04-01)
参考文献数
51
被引用文献数
17

Zirconium diboride based ceramics, owing to their superior high temperature properties are potential materials for use as leading edge components in hypersonic space vehicles. However, the difficulty in sintering these ultra high temperature ceramics limit their applications to some extent. Sintering of such materials is usually accomplished by resorting to advanced sintering techniques such as Spark Plasma Sintering (SPS) accompanied by sinter aids to improve the sinterability. In this backdrop, the current work investigates the effect of Ti addition on the mechanical properties and sinterability of ZrB2–based ceramic composites. Tailored addition of Ti to ZrB2–18 wt. % SiC baseline composites not only improves the densification but also increases hardness and indentation toughness, when sintered using Multi Stage Spark Plasma Sintering technique. Microstructure and X-ray diffraction analysis reveals the presence of ultrafine grains of ZrB2 and SiC, which is found to be effective in obtaining a good hardness (up to 29 GPa) and reliable indentation toughness (up to 9 MPa·m1/2).
著者
Wataru UNO Kotaro FUJII Eiki NIWA Shuki TORII Ping MIAO Takashi KAMIYAMA Masatomo YASHIMA
出版者
公益社団法人 日本セラミックス協会
雑誌
Journal of the Ceramic Society of Japan (ISSN:18820743)
巻号頁・発行日
vol.126, no.5, pp.341-345, 2018-05-01 (Released:2018-05-01)
参考文献数
46
被引用文献数
8

Crystal structure and neutron scattering length density distribution of a pyrochlore-type ytterbium titanate Yb2Ti2O7 have been investigated by in situ neutron powder diffraction measurements at 293 and 1173 K, Rietveld analysis and maximum-entropy method (MEM). In the MEM neutron scattering length density distributions of Yb2Ti2O7, the oxide ion O48f bonding to Ti cation was relatively localized at lower temperature of 293 K, while it was largely distributed at a higher temperature of 1173 K. At 1173 K, one oxide-ion diffusion path along the 〈110〉 unshared edge of TiO6 octahedron was clearly visualized and the other oxide-ion diffusion path along 〈100〉, strictly 〈2 −8x(O48f) + 3 8x(O48f) − 3〉, shared edge of TiO6 octahedron was also indicated. Here x(O48f) is the atomic coordinate x of O48f anion. The MEM neutron scattering length density distribution and difference bond valence sum map at 1173 K strongly suggested that the energy barrier for oxide-ion migration along 〈110〉 directions was lower than that along the 〈100〉 one. Oxide ions three-dimensionally diffuse through both the 〈110〉 and 〈100〉 paths across the unit cell.
著者
Shunsuke MURAI Tomohiko MATOBA Christopher T. NELSON Takuya KOMINE Koji FUJITA Xiaoqing PAN Katsuhisa TANAKA
出版者
公益社団法人 日本セラミックス協会
雑誌
Journal of the Ceramic Society of Japan (ISSN:18820743)
巻号頁・発行日
vol.121, no.1416, pp.710-713, 2013-08-01 (Released:2013-08-01)
参考文献数
21

We have prepared composites with anisotropic microstructure consisting of silver nanoparticles and zinc oxide pillars using an oblique angle deposition technique, and examined the optical response originating from their anisotropic morphology. The sample was obtained in three steps. First, the assembly of silver nanoparticles was prepared on a silica glass substrate by electron-beam deposition of the silver thin film and subsequent heat treatment. Next, zinc oxide was obliquely grown by using a pulsed laser deposition. Finally the zinc oxide was crystallized by the post annealing to make an array of inclined pillars grown on the top of the silver nanoparticles. The structure and morphology of the composites were elucidated by a combination of X-ray diffraction analysis and transmission electron microscopy. Optical rotation spectroscopy clarifies that the composite shows optical birefringence due to its inclined pillar morphology. The optical rotation spectrum exhibits two peaks, one being associated to the localized surface plasmon resonance of the silver nanoparticles and the other the excitons in the zinc oxide pillars. The present fabrication method is simple and can be applied to obtain anisotropic composites with relatively large dimensions.
著者
下野 泰雄 西田 充 関 八千穂
出版者
公益社団法人 日本セラミックス協会
雑誌
窯業協會誌 (ISSN:00090255)
巻号頁・発行日
vol.95, no.1101, pp.494-502, 1987-05-01 (Released:2010-04-30)
参考文献数
26

This report describes the formation of foam glass made from abundant glassy volcanic ashes existing in south Kyusyu (Kagosima-ken), Hokuriku (Ishikawa-ken), and Hokkaido. A specified batch composition in the system volcanic ash, sodalime-silica glass, and sodium silicate (anhyd.), has been calcinated at 900°C for 10 minutes in an electric furnace to obtain foam glass. This experiment has provided various usefull foam glasses with desired quality, for insulating materials (bulk density: 0.23Mg/m3, thermal conductivity: 0.07W/m·K) and inner or/and outer sawing materials (bulk density: 0.65Mg/m3, thermal conductivity: 0.14W/m·K). All volcanic ashes used in this experiment has satisfied requirements for raw materials. When the six definite straight lines are extrapolated to find by plotting the physical properties (bulk density, thermal conductivity, average pore diameter) of foam glass on various amounts of the soda-lime-silica glass at the right-angled coordinates definates x-axis as the amount of sodium silicate (anhyd.) including the glass batch, and y-axis as the physical properties, every lines intersected and converged on one point. When the intersectional coordinates are the bulk density and thermal conductivity of foam glass, all the values of x-axis are the same. And, when the intersectional coordinates are the average pore diameter of foam glass except Sample No. 2, all the values of y-axis are the same. It was found that all the glassy volcanic ashes used in this experiment have essentially the same property ranging from south Kyusyu to Hokkaido.
著者
友沢 稔 高田 雅介 John ACOCELLA E. Bruce WATSON 高森 剛
出版者
公益社団法人 日本セラミックス協会
雑誌
窯業協會誌 (ISSN:00090255)
巻号頁・発行日
vol.91, no.1056, pp.377-383, 1983-08-01 (Released:2010-04-30)
参考文献数
31
被引用文献数
7 8

約8wt%までの水を含むNa2O・3SiO2ガラスを高温高圧下で合成し, そのガラス転移点 (Tg) をDTA法により測定した. ガラス中の水はTgより高温で発泡を伴って溶離した. ガラス転移点と発泡温度はともに含水量の増加につれて減少した. 含水量の変化に対するガラス転移点の変化を高分子の可塑剤に対する種々の方程式と比較し, OHと分子状H2Oの両方の寄与を考慮に入れた方程式により, 最もよく記述されることを見出した. OHはTgを急激に下げ, 一方分子状H2Oは単にガラスを薄める効果によりわずかにTgを下げることが結論付けられた.
著者
功刀 雅長 高橋 克明 沢井 郁太郎
出版者
公益社団法人 日本セラミックス協会
雑誌
窯業協會誌 (ISSN:00090255)
巻号頁・発行日
vol.69, no.788, pp.261-270, 1961-08-01 (Released:2010-04-30)
参考文献数
5

A model of a bridge-wall tank was made from plastics to the scale 1/50. Molten glass was replaced by 82% glycerin and its flow in the model under conditions satisfying as fare as possible the law of similitude was studied by the following method. Grains of plastics covered with aluminium powder, whose specific gravity was made as nearly as possible the same as that of glycerin, were introduced as tracer. Illumination with a thin sheet of light across the tank made the motion of the tracer particles visible, and the velocity distribution in the flowing glycerin was estimated from photographic records of the tracks. The temperature distribution in the fluid was measured by Cu-constantan thermocouples. The effect of changes of heat input from the top surface and the arrangement of heaters on the flow patterns and the temperature distribution was investigated.
著者
栗原 和信
出版者
公益社団法人 日本セラミックス協会
雑誌
窯業協會誌 (ISSN:00090255)
巻号頁・発行日
vol.67, no.757, pp.C12-C20, 1959-01-01 (Released:2010-04-30)
参考文献数
35
被引用文献数
1 1
著者
樋口 昌史 淺香 隆 片山 恵一
出版者
公益社団法人 日本セラミックス協会
雑誌
日本セラミックス協会 年会・秋季シンポジウム 講演予稿集
巻号頁・発行日
vol.2003, pp.226, 2003

東海大学工学部は、2000年春の改組によって旧工業化学科が"応用化学科"と"生命化学科"とに分かれて誕生し、定員は80名である。学生の半数は一般受験によって入学するが、その他、一般推薦・自己推薦・AO推薦で入学した者に付属高校からの入学者も加わり、様々な学生が入学してくる。このため、学力差が大きいことは勿論、自分の無知さに気づかない学生や学習意欲のない学生が増えているのも事実である。本発表では、このような本学応用化学科の現状を無機化学関連科目を中心に話し、大学教育の問題点を探ってみたい。
著者
吉田 正尚
出版者
公益社団法人 日本セラミックス協会
雑誌
日本セラミックス協会 年会・秋季シンポジウム 講演予稿集
巻号頁・発行日
vol.2007, pp.95, 2007

ポリエチレン(PE)等のポリオレフィン(PO)基材は着色等の後加工による表面修飾がその化学構造から原理的に困難な材料である。これに対して発表者はゾル-ゲル法を独自に応用発展させた新しい方法により後加工でPO基材へ表面修飾できる方法を見いだした。これまでの基礎的検討により、難染色性のPEへの着色等の表面修飾が容易に可能であることが分かった。それは、1.様々な各種機能性微粒子(メゾスコピック~ナノ粒径範囲)、2.微粒子と基材の両方に親和性のある結合剤(シラン化合物)、3.高い結晶(配向)性を有するPO基材、の3つを組み合わせた全く新しい微粒子固定方法である。具体的には、微粒子・結合剤・結晶性PO基材を液相中(水または有機溶媒)に共存させると経時的に微粒子がPO基材表面に自己集合・自己組織化していく物理現象を利用した全く新たな製造方法である。