TaC-Ni オヨビ TaC-Ni-Moケイサーメット ノ ショウケツ ト ビサイコウゾウ ノ カンサツ

TaC-Ni and TaC-Ni-Mo cermets were sintered at 1150～1400℃ in a vacuum of 5×10^ Torr for 1hr. The effect of addition of molybdenum on the sinterability and the microstructure of TaC-base cermets were studied by measurments of relative density and micro・Vicker\u27s hardness and Auger electron microscopy. Relative densities and hardness of the TaC-Ni-Mo cermets were higher than these of the TaC-Ni cermets. In TaC-Ni-Mo cermets, liquid phase appeared relatively lower temperature (1150～1250℃) than in TaC-Ni cermet (about 1290℃) and it is estimated that the wettability between solid and liquid phases is so improved that the grain growth of TaC is suppressed. It was obsreved that all molybdenum resolves to nickel phase and TaC silghtly resolves to nickel or Ni-Mo phase

ケイコウプローブ ニ ヨル メチルカシクロデキストリン ノ ホウセツケイタイ ノ ケントウ

The fluorescence spectra of 8-anilino-1-naphthalene sulfonic acid (ANS) and 7-toluidino-2-naphthalene sulfonic acid (TNS) were observed with or without various cyclodextrins. From the change of fluorescence intensity, the association constants between cyclodextrins and fluorescent probes (K) and the fluorescence intensity constants (i_0) for each cyclodextrin complex were calculated. The value of i_0 depended on the probe\u27s local microenvironment. These parameters assist in explication of the complex formation. And the effect of methylation of cvclodextrin for inclusion behavior is also indicated

TiOショウケツタイ ノ ブツリテキ ショセイシツ ニ オヨボス MgOテンカ ノ エイキョウ

MgOを0, 1, 5, 10, 15および20 mo1%添加したTiO焼結体の物理的性質を測定し次の結果を得た.生成相はすべてNaCl型構造のTiOで,MgOはTiO相に約15%まで固溶した.MgO添加によりTiO焼結体の粒成長は抑制され,添加量の増加とともに平均粒径は減少した.MgO添加量の増加に従って焼結性は低下し,相対密度は減少した.一般に焼結体の硬さの増加に対するMgO添加の効果は大きくなく, 15%添加により無添加の最大値よりわずかに大きいビッカース硬度1350が得られた.焼結体の電気抵抗はMgO量の増加とともに増加した.これはMgOの添加による粒成長の抑制と気孔率の増加を原因とする.Some physical properties of sintered TiO doped with 0, 1, 5, 10, 15 and 20 mol% MgO were measured. All of the Ti phases obtained were identified to be NaCl type structure and solid solubility of MgO in TiO phase was assumed to be about 15%. The grain growth of TiO was suppressed by the doping of Mg0 and as the addition of MgO increased, the grain size decreased. Moreover, as the addition of MgO increased, the sinterability of TiO decreased and the relative density decreased. The effect of the addition of MgO on the hardness of TiO ceramics was not so significant. 0nly when 15 mo1% MgO was doped, the microvicker\u27s hardness was about 1350, slightly larger than that of the maximum value of TiO ceramics without any additives. The electrical resistivity of TiO ceramics increased with an increase of the addition of MgO. This is assumed to be by reasons of the suppression of grain growth and the increase of the porosity of TiO ceramics

ヘンイキンゾクゲンソ ノ ホウカブツ ノ コウゾウ ト ゴウセイ

The borides of transition metal elements generally display a number of unique properties including high melting point, very high hardness and strength. high thermal conductivity and relatively low thermal expansion as well as high chemical stability, and then are expected as potential candidates requiring high-temperature strength and stability under severe environments. ln this paper, crystal structure, classification, synthesis, application and preparation of these boride ceramics are reviewed

バナジウム テンカブツ ITOマク ノ ビコウゾウ ト デンキトクセイ

Microstructure, crystallinity and electrical properties of vanadium-added ITO (In : Sn : V=93. 3 : 3.7 : 3.0 at. %) films, which were prepared using conventional rf magnetron sputtering, were compared with ITO (In : Sn=97.8 : 2.2 at. %) films without vanadium. At a substrate temperature of 300℃, the resistivity (ρ) of 1.58×10^ Ωcm with a carrier density (n) of 1.03×10^cm^ and Hall mobility (μ) of 38.3 cm^2 V^s^ was obtained for the vanadium-added ITO film, whereas ρ=3.27×10^ Ωcm with n=3.99×10^cm^ and μ=48.0cm^2V^s^ was obtained for the ITO film without vanadium addition. The vanadium addition enhanced the crystallinity and the densification of In_20_3 lattice. The enhanced electrical conductivity (increase in the carrier density) due to vanadium addition is explamed by the increase in the efficiency of Sn doping. The effect of vanadium addition is similar to that of silver addition into ITO films as reported elsewhere by the present authors

カガクリョウロンテキ コウジュンドチタンサンバリウムビフンマツ ノ ショウケツ

ビス(シュウ酸)酸化チタン(IV)バリウムの熱分解により生成した化学量論的,高純度BaTiO_3微粉末の焼結性について検討し次の結果を得た.(1)熱分解によって生成したBaTiO_3粉末は分解温度が高くなるに従って粒成長い,粉体の表面エネルギーは減少する.(2)分解温度900℃のとき焼結体の相対密度は最大値を示した.すなわち最適熱分解温度は900℃である.またBaTiO_3粉末の焼結には少なくとも1250℃以上の温度が必要である.(3)焼結体の結晶粒径は,焼結温度の上昇に従って正常な粒成長を示すことから,熱分解により生成したBaTi0_3粉末は狭い粒径分布をもち高純度であると推定できる.(4)BaTi0_3焼結体の室温における誘電率は,BaCO_3とTiO_2から出発する従来の方法により調整されたBaTi0_3セラミックスの誘電率よりはるかに高い値を示した.(5)BaTiO_3焼結体の結晶粒径が小さくなるに従って,室温における誘電率は増加する.We studied the sintering behavior of stoichiometric and high purity barium titanate fine powder Pioduced by the pyrolysis of barium titanium (IV) bis (oxalate) oxide at various temperatures. Titanate particle size increases with pyrolysis temperature. Pyrolysis of the oxalate at 900℃ produces most sinterable fine powder and the sintering of the titanate fine power needs temperature of 1250℃ at least. Microstructure of the titanatae ceramics shows normal grain geowth and this suggests that the titanate powders from the oxalate have relatively narrow particle size-distribution and high purity. The dielectric constant of the titanate ceramics at room temperature is much higher than those of conventional barium titanate ceramics. Dielectric constant at room temperature decreases as grain size increases in the range of this study

チョウビリュウ シチッカアルミニウム フンマツ ノ ショウケツ

Low temperature sinterability of AIN powders with different particle sizes was examined using Y_20_3 as a sintering additive. Samples used in this paper were plasma nitridation AIN with 0.09μm, metal nitridation AIN with 1.2μm, and carbothermal reduction and nitridation with 0.7 and 2.0μm in diameter. Fine powder with higher specific surface area showed higher sinterability at relatively low sintering temperature. Plasma nitridation powder showed excellent sintering behavior with 90% of theoretical density of AIN at 1600℃. No liquid phase formation was observed in the sample sintered between 1400 and 1700℃ with addition of Y_20_3. Processing parameters, i. e., solvent kinds for mixing or amount of binder addition strongly affected the sinterability of AIN in the case of plasma nitridation powder. Low temperature sintering without liquid phase formation needs careful powder processing to control the agglomeration and oxygen contents

オートクレーブ オ モチイタ ヨウキョクサンカ ニヨル サンカニッケルハクマク ノ サクセイ ト ヒョウカ

Nickel thin films (thickness ; ～1μm) were oxidized by the method what Yoshimura et al called hydrothermal electrochemical synthesis in an aqueous solution of LiOH (O-1N) at high temperature (100-200℃) in an autoclave with the anodic current of 0-100 mA/cm^2 for O-120 min. The reacted specimens were analyzed by FE-SEM, Auger electron spectroscopy, XPS, SIMS and thin-film X-ray diffraction analysis. NiO and Ni(OH)_2 coexisted. Ni(OH_2 were detected mainly near the exposed surface of the films. NiO was remarkably formed at high temperature and high current density in the present experimental conditions. Lithium was detected in the film although no definite conclusion for the formation of solid solution into NiO

N-ビオチニル-アミノ-β-シクロデキストリン ノ ゴウセイ

The fact that α-biotin serves as a covalently bound "C0_2 carrier" is now unequivocally established. Though model studies such as carboxylation on ureid l\u27-N-of biotin has been reported, no appropriate biomimetic model study for a "C0_2 carrier" has been carried out. The titled compound(I)in which the biotinyl group is bound to an amide linkage withβ-cyclodextrin, was prepared with active-ester method in good yield. Compound I was purified by taking with preparative HPLC. The structure of (I) was providedby ^1H-nmr, ^C-nmr, elemental analysis, HPLC and the paper choromatography of hydrolyzates, and decided to be 6-(mono-N-biotinyl)-amino-β-cyclodextrin