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1.
Kazuyuki Suzuki Wataru Sakamoto Toshinobu Yogo Shin-ichi Hirano 《Journal of the American Ceramic Society》1999,82(6):1463-1466
K(Ta,Nb)O3 (KTN) thin films have been prepared by the chemical solution deposition method. KTN precursors consisted of a uniform mixture of K[Ta(OC2 H5 )6 ] and K[Nb(OC2 H5 )6 ] with interaction at the molecular level. Perovskite KTN thin films with the desired composition (Ta/Nb = 65/35, 50/50, and 35/65) were synthesized from the precursor solutions by the dip coating method. KTN thin films with (100) preferred orientation were successfully synthesized on MgO(100) and Pt(100)/MgO(100) substrates. X-ray pole figure measurements showed that grains of KTN films had a prominent three-dimensional regularity on MgO(100) and Pt(100)/MgO(100) surfaces. The Curie temperatures of KTN films decreased with increasing Ta/Nb ratio. Typical P-E hysteresis loops were observed for KTN thin films of three compositions on Pt(100)/MgO(100) substrates. The values of remanent polarization ( P r ) of KTN films increased as the Ta/Nb ratio changed from 65/35 to 35/65. 相似文献
2.
Shin-ichi Hirano Toshinobu Yogo Ko-ichi Kikuta Toshiyuki Morishita Yasuhiro Ito 《Journal of the American Ceramic Society》1992,75(6):1701-1704
Perovskite potassium tantalate niobate (KTN) powders and thin films were synthesized from a metal alkoxide solution. Homogeneous KTN coating solutions were prepared from KOC2 H5 , Ta(OC2 H5 )5 , and Nb(OC2 H5 )5 in absolute ethanol. The precursor crystallized to pyrochlore at ∼ 650°C, and then to perovskite at ∼ 750°C, depending upon Ta:Nb ratio. H2 O vapor during calcination was found to play a prominent role in the direct and predominant crystallization of perovskite films with preferred orientation. Highly oriented KTN films of perovskite structure were successfully prepared on MgO (100) substrates at 675°C. 相似文献
3.
Toshinobu Yogo Wataru Sakamoto Tadayuki Isaji Koichi Kikuta Shin-ichi Hirano 《Journal of the American Ceramic Society》1997,80(7):1767-1772
Transparent and highly oriented Ba2 NaNb5 O15 (BNN) thin films have been prepared by using metal alkoxides. A homogeneous precursor solution was prepared by the controlled reaction of NaOC2 H5 , Nb(OC2 H5 )5 , and barium metal. The BNN precursor included a molecular-level mixture of NaNb(OC2 H5 )6 and Ba[Nb(OC2 H5 )6 ]2 in ethanol. The alkoxy-derived powder crystallized to a low-temperature phase, and then transformed to orthorhombic BNN (tungsten bronze) at 600°C. BNN precursor films on substrates crystallized to orthorhombic BNN at 800°C via the low-temperature phase. Highly (002) oriented BNN films of tungsten bronze structure were successfully prepared on MgO (100) substrates at 700°C by using BNN underlayer. 相似文献
4.
Tadasu Hosokura Keisuke Kageyama Hiroshi Takagi Yukio Sakabe 《Journal of the American Ceramic Society》2009,92(1):253-255
Epitaxially grown single-crystal perovskite (100) three-axis-oriented (Ba0.7 Sr0.3 )TiO3 thin films were prepared on a (100) platinum-coated (100) magnesium oxide (MgO) single-crystal substrate by the chemical solution deposition method using a solution derived from Ba(CH3 COO)2 , Sr(CH3 COO)2 , and Ti(O- i -C3 H7 )4 .
The growth of the film was found to depend on the annealing condition. A (Ba,Sr)TiO3 thin film annealed at 1073 K was found to be a single crystal by transmission electron microscope. The single-crystal film exhibited a (100) three-axis orientation that followed the (100) orientation of the Pt substrate, as observed from an X-ray pole figure measurement and selected area electron diffraction patterns. 相似文献
The growth of the film was found to depend on the annealing condition. A (Ba,Sr)TiO
5.
Atsushi Aruga Yoshikazu Nakamura Tsuneharu Aoi Yoshihisa Watanabe Shigekazu Hirayama Shirou Fujimoto 《Journal of the American Ceramic Society》1993,76(11):2939-2941
0.4Pb(Mg1/3 Nb2/3 )O3 –0.3Pb(Mg1/2 W1/2 )O3 –0.3PbTiO3 + x MgO ( x = 0 to 0.04) were prepared by a metal alkoxide method. The percent of perovskite phase of the calcined powders increased with increased calcination temperatures. About 89% of perovskite phase was obtained at 1050°C. The dielectric constant of the pellets fired at 1100°C was increased by the addition of 10 wt% excess Mg(OC2 H5 )2 and had a maximum value of 7532 at 1 kHz. 相似文献
6.
A modified sol-gel process has been developed for the production of thin films of PbTiO3 . The new route uses the mixed ligand complex titanium diisopropoxide bis(acetylacetonate), Ti(OC3 H7 )2 (CH3 COCHCOCH3 )2 , in place of titanium tetraisopropoxide, Ti(OC3 H7 )4 . For base-catalyzed conditions, the maximum thickness of crack-free PbTiO3 films after one high-temperature firing cycle is 1 μm. This value represents a twofold increase in thickness over that obtained using existing sol-gel routes based on Ti(OC3 H7 )4 . 相似文献
7.
Synthesis of Potassium Niobate from Metal Alkoxides 总被引:1,自引:0,他引:1
Preparation of potassium niobate from metal alkoxides was investigated. Potassium-niobium ethoxide, KNb(OC2 H5 )6 , and potassium-niobium propoxide, KNb(OC3 H7 )6 , were synthesized and subsequently hydrolyzed using several water concentrations (0.75 to 6.0 mol of water/(mol of alkoxide)). Rapid precipitation of potassium-deficient particles occurred when higher concentrations of water were used. This resulted in the formation of a multiphase material after calcination, as X-ray diffraction showed the presence of both KNbO3 and potassium-deficient oxide phases(s). Single-phase KNbO3 could be prepared by two methods: (1) hydrolysis of KNb(OC3 H7 )6 /propanol solutions using 1 mol of water (per mole of propoxide) added as a water/propanol solution and (2) hydrolysis of KNb(OC2 H5 )6 /ethanol solutions using 1 mol of water (per mole of ethoxide) added as a water/methanol solution. The latter method provided advantages of low calcination temperature for the formation of single-phase KNbO3 and low weight loss after calcination. 相似文献
8.
Masayuki Nogami Yoichi Goto Toshihiro Kasuga 《Journal of the American Ceramic Society》2003,86(9):1504-1507
The effect of zirconium ions on glass structure and proton conductivity was investigated for sol-gel-derived P2 O5 –SiO2 glasses. Porous glasses were prepared through hydrolysis of PO(OCH3 )3 , Zr(OC4 H9 )4 , and Si(OC2 H5 )4 . Chemical bonding of the P5+ ions was characterized using 31 P-NMR spectra. The phosphorous ions, occurring as PO(OH)3 in the ZrO2 -free glass, were polymerized with one or two bridging oxygen ions per PO4 unit with increased ZrO2 content. The chemical stability of these glasses was increased significantly on the addition of ZrO2 , but the conductivity gradually decreased from 26 to 12 mS/cm at room temperature for 10P2 O5 ·7ZrO2 ·83SiO2 glass. A fuel cell was constructed using 10P2 O5 ·5ZrO2 ·85SiO2 glass as the electrolyte; a power of ∼4.5 mW/cm2 was attained. 相似文献
9.
Jang-Sik Lee Q. X. Jia Jung-Ho Park Seung-Ki Joo Woo Seok Yang Nam Kyeong Kim Seung Jin Yeom Jae Sung Roh 《Journal of the American Ceramic Society》2004,87(4):720-723
Ferroelectric SrBi2 (Ta,Nb)2 O9 (SBTN) thin films were deposited on Pt (200 nm)/TiO x (40 nm)/SiO2 (100 nm)/Si substrates by metal-organic decomposition. The effects of bombardment from accelerated argon and oxygen ions on the properties of SBTN thin films were investigated. It was found that the argon ion bombardment could decrease the crystallization temperature owing to the increase of internal energy of the films. Also, the oxygen vacancies at the interface between the SBTN film and platinum bottom electrode or at grain boundaries in the film were passivated through the oxygen ion treatment, resulting in the improved electrical properties. By optimizing the process parameters and using bombardment of accelerated argon and oxygen ions, SBTN films with good ferroelectric and electrical properties could be obtained, at a temperature as low as 650°C. 相似文献
10.
Structural Investigations of Prehydrolyzed Precursors Used in the Sol-Gel Processing of Lead Titanate 总被引:1,自引:0,他引:1
A variety of titanate gels were prepared from lead acetate and titanium isopropoxide in methoxyethanol. In the present study, 1 H and 13 C Fourier transform-nuclear magnetic resonance and mass spectroscopic techniques were used to identify the structure of the lead and titanium precursors formed from lead acetate and titanium isopropoxide, respectively, when refluxed in methoxyethanol. The lead and titanium precursors were determined to be Pb(OOCCH3 ) (OC2 H4 OCH3 ). x H2 O, where x < 0.5, and Ti2 (OC2 H4 OCH3 )8 , respectively. Similar spectroscopic procedures were applied to identify the lead titanium complex formed from the reaction between lead and titanium precursors. 相似文献
11.
Fine Patterning and Characterization of Gel Films Derived from Methyltriethoxysilane and Tetraethoxysilane 总被引:1,自引:0,他引:1
Atsunori Matsuda Yoshihiro Matsuno Masahiro Tatsumisago Tsutomu Minami 《Journal of the American Ceramic Society》1998,81(11):2849-2852
Pregrooves of 1.6 µm pitch for optical data storage have been embossed successfully by pressing a stamper against x CH3 Si(OC2 H5 )3 (100 - x )Si(OC2 H5 )4 -derived gel films (60 ≤ x ≤ 100 mol%) on glass-disk substrates of 130 mm diameter. When x is <40 mol%, the resultant films are too hard to emboss patterns uniformly. The shrinkage of the patterns is ∼4% for all the films when 60 lessthan equal to x lessthan equal to 100 mol%, even after heat treatment at 350°C, so that the nearly net negative shape of the stamper is preserved. The methyl groups in the films decompose at temperatures from 500° to 600°C. 相似文献
12.
Yongli Wang Dragan Damjanovic Naama Klein Evelyn Hollenstein Nava Setter 《Journal of the American Ceramic Society》2007,90(11):3485-3489
Compositional inhomogeneity is examined in Li- and Ta-modified potassium sodium niobate (K,Na)NbO3 perovskite ceramics. The inhomogeneous distribution of the A-site (K and Na) and B-site (Nb and Ta) cations is found to be correlative. The inhomogeneity could not be eliminated by prolonged high-temperature annealing in samples prepared by direct mixing of alkaline carbonates and Ta and Nb oxides. In contrast, the precursor method, where a (Nb x Ta1− x )2 O5 solid solution was first formed, led to a considerably improved compositional homogeneity and appreciably enhanced dielectric, ferroelectric, and piezoelectric properties. Our results suggest that more attention needs to be paid toward controlling the compositional fluctuation of this complex solid solution system. 相似文献
13.
Toshinobu Yogo Wataru Sakamoto Tadayuki Isaji Masao Ichida Arao Nakamura Shin-ichi Hirano 《Journal of the American Ceramic Society》1999,82(10):2672-2676
Ba2 NaNb5 O15 (BNN) thin films with a tungsten bronze structure were fabricated using a precursor solution that was synthesized from barium, sodium, and niobium alkoxides. Highly (002)-oriented BNN films were prepared successfully on Pt(100)/MgO(100) substrates at 700°C, using a BNN underlayer. X-ray pole-figure measurement showed that the BNN films that crystallized on Pt(100)/MgO(100) substrates had two in-plane orientations. The remanent polarization and coercive field of the BNN film (thickness of 1.0 µm) that was crystallized at 700°C were 12.3 µC/cm2 and 101 kV/cm, respectively, at –150°C (123 K). BNN films on fused silica substrates exhibited second harmonic generation upon irradiation with 1064 nm light. 相似文献
14.
Yoshikazu Nakamura Tsuneharu Aoi Atsushi Aruga Yoshihisa Watanabe Shigekazu Hirayama Shirou Fujimoto 《Journal of the American Ceramic Society》1995,78(6):1457-1462
A perovskite structure of 0.4Pb(Mg1/3 Nb2/3 )O3 ·0.3Pb(Mg1/2 W1/2 )O3 ·0.3PbTiO3 was prepared from metallo-organic precursors through the solid-state reaction of the mixed gels. Three types of mixed gels were crystallized to obtain PbTiO3 , MgNb2 O6 , and MgWO4 powders. These powders were calcined at 900°C after mixing with a stoichiometric amount of Pb(CH3 COO)2 ·3H2 O. The dielectric constant of the ceramic fired at 900°C was improved by adding an excess of 10 mol% Mg(OC2 H5 )2 , and the ceramic achieved X7T specification of the Electric Industries Association standard. The dielectric loss was reduced by adding an excess of 5 mol% Pb(CH3 COO)2 ·3H2 O. 相似文献
15.
Ink Jet Printing of Microdot Arrays of Mesostructured Silica 总被引:1,自引:0,他引:1
M. Mougenot M. Lejeune J. F. Baumard C. Boissiere F. Ribot D. Grosso C. Sanchez R. Noguera 《Journal of the American Ceramic Society》2006,89(6):1876-1882
We report a process for preparing microdot arrays of SiO2 from a tetraethoxysilane precursor containing either a cationic (CTAB) or non-ionic surfactant. Controlling the ink jet deposition parameters and precursor hydrolysis made it possible to obtain mesoporous silica with a Pm 3 n cubic structure, using CTAB, or an Fmmm orthorhombic structure, using a non-ionic surfactant. The addition of hydrophobic organosilane F3 C(CF2 )5 CH2 CH2 Si(OC2 H5 )3 leads to the most regular and best-defined three-dimensional microdot array with a constant diameter of 155 μm and a regular space of 250 μm. 相似文献
16.
Wataru Sakamoto Toshinobu Yogo Akihiro Kawase Shin-ichi Hirano 《Journal of the American Ceramic Society》1998,81(10):2692-2698
Transparent and highly oriented K x (Sr0.5 Ba0.5 )1− x /2 Nb2 O6 ( x = 0.2, 0.4) (KSBN) thin films have been synthesized by a chemical solution deposition method. A homogeneous and stable KSBN precursor solution was prepared by controlling the reaction of metallo-organics. K0.4 Sr0.4 Ba0.4 Nb2 O6 ( x = 0.4, K0.4 SBN50) and K0.2 Sr0.45 Ba0.45 Nb2 O6 ( x = 0.2, K0.2 SBN50) powders and thin films directly crystallized to the tetragonal tungsten bronze phase above 600°C. The thin films were crystallized on MgO(100) and Pt(100)/MgO(100) with c -axis preferred orientation. Two crystal lattice planes of K0.4 SBN50 and K0.2 SBN50 were intergrown at an orientation of 18.5° on MgO(100) and Pt(100)/MgO(100). K0.4 SBN50 thin film on Pt(100)/MgO(100) showed the typical hysteresis loop ( P r = 22 µC/cm2 , E c = 99 kV/cm at −190°C). The change in remnant polarization with temperature is strongly related to the diffuse phase transition of the epsilon- T curves. 相似文献
17.
Molecular dispersions of amorphous siliceous materials doped with organic molecules were prepared by a sol-gel process in which Si(OC2 H5 )4 was hydrolyzed in neutral or acidic solution. An amorphous silica which was doped with quinizarin on the order of 5×10−5 mol/mol SiO2 showed photochemical hole burning at ∼4 K. 相似文献
18.
The phase stabilities in the(1−x)Ba(Zn1/3 Ta2/3 )O3 (BZT)-xBaZrO3 (BZ)system have been investigated using samples prepared by the mixed oxide method. The substitution of Zr4+ destabilizes the 1:2 cation ordering in BZT and pro-motes the formation of a cubic, 1:1 ordered structure with a doubled perovskite repeat. The homogeneity range of the 1:1 phase extends from x = 0.04 to approximately x = 0.25; substitutions beyond this range stabilize a disordered perovskite. The limits of stability of the 1:1 ordering coin-cide with compositions previously found to exhibit anoma-lies in their dielectric loss. The range of homogeneity is consistent with a "random layer" model for the 1:1 ordered "Ba{β';1/2 β1/2 }O3 " structure. In this model the B× positions are assumed to be occupied exclusively by Ta5+ , and the b× sites by a random distribution of Zn2+ , Zr4+ , and the remaining Ta 5+ cations. The validity of the model, where the ordered solid solutions can be represented by Ba{[Zn2− y /3 Ta(1−2 y )/3 Zr y ]1/2 [Ta]1/2 }O3 (y =2x)was con-firmed by Rietveld refinements conducted using data col-lected with a synchrotron X-ray source. 相似文献
19.
Chunzhong Li † Jinyi Han Zongtao Zhang Hongchen Gu 《Journal of the American Ceramic Society》1999,82(8):2044-2048
A process of coating Al2 O3 particles with TiO2 by hydrolysis of Ti(OC4 H9 )4 using chemical vapor deposition in a rotary reactor has been developed. The process resulted in (1) a coating film of TiO2 which was compact and uniform with the fraction of TiO2 being 0.1%–10.0% and (2) an amorphous TiO2 coating at a low reaction temperature converted to anatase at a reaction temperature higher than 673 K. 相似文献
20.
BaTiO3 coating films were prepared from Ba(CH3 COO)2 –Ti(OC3 H7 i )4 –H2 O–CH3 COOH–C3 H7 i OH solutions containing poly(vinylpyrrolidone) (PVP) via single-step, nonrepetitive dip coating. The critical thickness—i.e., the maximum film thickness achieved without crack formation via nonrepetitive dip coating—was successfully increased by incorporation of PVP in the precursor solution. Relatively dense, crack-free BaTiO3 films >1 μm in thickness were achieved via single-step deposition using a solution containing PVP of average molecular weight of 630 000. Incorporation of an excess amount of PVP, however, led to a decrease in the critical thickness. Higher-molecular-weight PVP was more effective in increasing the critical thickness, whereas N-vinyl-2-pyrrolidone monomers did not affect the critical thickness. Stepwise heating of the gel films resulted in increased optical transmittance of the films, accompanied by film densification. 相似文献