共查询到20条相似文献,搜索用时 31 毫秒
1.
Shuichi Arakawa Kenji Mogi Ko-ichi Kikuta Toshinobu Yogo Shin-ichi Hirano Yoji Seki Mitsutoshi Kawamoto 《Journal of the American Ceramic Society》1997,80(11):2864-2668
Oriented (Ti,Sn)O2 thin films with modulated microstructure were successfully synthesized on sapphire substrates by using sol–gel processing combined with spinodal decomposition. The degree of orientation of (Ti0.5 Sn0.5 )O2 thin films increased in the following order: sapphire (0001), (11 0), and (01 2). (Ti0.5 Sn0.5 )O2 thin films underwent spinodal decomposition at 900°C by annealing. The variation of the 2theta value of the 202 reflection of (Ti0.5 Sn0.5 )O2 films showed the typical behavior of spinodal decomposition. The rate of spinodal decomposition of the (Ti0.5 Sn0.5 )O2 films on sapphire (11 0) was faster than that on sapphire (01 2) substrates. The characteristic modulated microstructure was observed for the spinodally decomposed (Ti0.5 Sn0.5 )O2 films on sapphire (01 2) substrates by transmission electron microscopy. (Ti0.3 Sn0.7 )O2 films on sapphire (01 2) substrates were binodally decomposed during annealing at 1300°C. 相似文献
2.
Shin-ichi Hirano Toshinobu Yogo Ko-ichi Kikuta Emi Asai Kiyoshi Sugiyama Hiroshi Yamamoto 《Journal of the American Ceramic Society》1993,76(7):1788-1792
(Co,Fe)3 O4 films were synthesized by the sol–gel method through metalorganic compounds. The (Co,Fe)3 O4 films (Co:Fe = 2:1) showed the characteristic behavior of the spinodal decomposition by heat treatments within the miscibility gap. The coercive force of the spinodally decomposed films increased from 0.9 kOe for a solid solution to 2.0 kOe for films that underwent the spinodal decomposition. The nonmagnetic phase (rich in Co) formed by the spinodal decomposition contributes to the pinning of the movement of magnetic domain walls. On the other hand, the (Co,Fe)3 O4 films (Co:Fe = 1:1) showed the typical feature of binodal decomposition during heat treatment within the miscibility gap. The binodally decomposed films showed a slight increase in the coercive force depending upon the evolution of the magnetic region. 相似文献
3.
Yongsheng Liu Laifei Cheng Litong Zhang Wenbin Yang Yongdong Xu 《International Journal of Applied Ceramic Technology》2008,5(3):305-312
Methane (CH4 ) and propylene (C3 H6 ) were used to fabricate a boron–carbon coating by a low-pressure chemical vapor deposition (LPCVD) technique. The effects of carbon precursors on the phase, microstructure, and bonding state of the deposits have been investigated. X-ray diffraction results show that the 2θ value of the deposit from the C3 H6 precursor shifts to 25.78° when the coating is deposited at 1223 K, and shifts to 26.1° when deposited at 1273 K, compared with the 2θ value of the pyrocarbon (PyC) peak deposited by LPCVD, which is 25.42°, and no boron–carbon (B–C) compound peak exists. However, the phases of coating deposited from CH4 include B25 C, B13 C2 , elemental carbon, and boron. X-ray photoelectron spectroscopy (XPS) results show that the percent contents of boron atom in the coatings from the CH4 precursor are 61.18% and 67.78% when deposited at 1223 and 1273 K, respectively, much higher than that from the C3 H6 precursor, 10.85% and 15.30%, respectively. Scanning electron microscopy (SEM) results show that the coatings deposited from CH4 have a coarse crystal-like morphology; however, the coatings deposited from the C3 H6 precursor are smooth. The formation of PyC from C3 H6 is more facile than that from CH4 , which leads to differences in the phase, atom content, and microstructure of coatings from CH4 and C3 H6 precursors. 相似文献
4.
Phase equilibrium relations in the system PbO–TiO2 –ZrO2 were studied by quenching in the range where the PbO content is 50 mole % and more. Isotherms were examined at 1100°, 1200°, and 1300°C and tie lines were determined between the liquid and solid solution in equilibrium. The incongruent melting point of PbZrO3 was 1570°C and the equilibrium between liquid, PbO-type solid, and PbZrO3 is peritectic. Pb(Zr,Ti)O3 solid solutions containing more than 14 mole % PbZrO3 decomposed to liquid, ZrO2 , and Pb(Zr,Ti)O3 and the decomposition temperature rises from 1340° to 1570°C with increasing PbZrO3 content. The system PbTiO3 –PbZrO3 should not be treated as a binary, but as a section of the ternary system. 相似文献
5.
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
6.
Toshinobu Yogo Koichi Kikuta Yasuhiro Ito Shin-ichi Hirano 《Journal of the American Ceramic Society》1995,78(8):2175-2179
Highly oriented K(Ta,Nb)O3 (Ta:Nb = 65:35) (KTN) thin films of perovskite structure were synthesized successfully on Pt(100)/MgO(100) substrates from a metal alkoxide solution through reaction control. Homogeneous KTN coating solutions prepared from KOC2 H5 , Ta(OC2 H5 )5 , and Nb(OC2 H5 )5 in ethanol were analyzed by 1 H, 13 C, and 93 Nb NMR spectroscopy. The KTN precursor included a molecular-level mixture of K[M(OC2 H5 )6 ] (M = Ta, Nb) units interacting in ethanol solution. X-ray pole figure measurement showed that perovskite KTN films crystallized on Pt(100)/MgO(100) substrates had not only a (100) orientation but also a three-dimensional regularity of grains. The remanent polarization and coercive field of the KTN film (thickness, 1.0 μm) crystallized at 700°C were 1.5 μC/cm2 and 8.7 kV/cm, respectively, at 225 K. 相似文献
7.
Shuichi Kawano Junichi Takahashi Shiro Shimada 《Journal of the American Ceramic Society》2003,86(9):1609-1611
Nano-sized TiO2 powders were prepared by controlled hydrolysis of TiCl4 and Ti(O-i-C3 H7 )4 solutions and nitrided in flowing NH3 gas at 700°–1000°C to form TiN. Nano-sized TiN was densified by spark plasma sintering at 1300°–1600°C to produce TiN ceramics with a relative density of 98% at 1600°C. The microstructure of the etched ceramic surface was observed by SEM, which revealed the formation of uniformly sized 1–2 μm grains in the TiCl4 -derived product and 10–20 μm in the Ti(O-i-C3 H7 )4 -derived TiN. The electric resisitivity and Vickers micro-hardness of the TiN ceramics was also measured. 相似文献
8.
Edwin Kroke Lars Loeffler Fred F. Lange Ralf Riedel 《Journal of the American Ceramic Society》2002,85(12):3117-3119
Aluminum nitride (AlN) powders were prepared from the oxide precursors aluminum nitrate, aluminum hydroxide, aluminum 2-ethyl-hexanoate, and aluminum isopropoxide (i.e., Al(NO3 )3 , Al(OH)3 , Al(OH)(O2 CCH(C2 H5 )(C4 H9 ))2 , and Al(OCH(CH3 )2 )3 ). Pyrolyses were performed in flowing dry NH3 and N2 at 1000°–1500°C. For comparison, the nitride precursors aluminum dimethylamide (Al(N(CH3 )2 )3 ) and aluminum trimethylamino alane (AlH3 ·N(CH3 )3 ) were exposed to the same nitridation conditions. Products were investigated using XRD, TEM, EDX, SEM, and elemental analysis. The results showed that nitridation was primarily controlled by the water:ammonia ratio in the atmosphere. Single-phase AlN powders were obtained from all oxide precursors. Complete nitridation was not obtained using pure N2 , even for the non-oxide precursors. 相似文献
9.
Do-Kyun Kwon Teppei Akiyoshi Hyeongjae Lee Michael T. Lanagan 《Journal of the American Ceramic Society》2008,91(3):906-909
Manganese dioxide (α-MnO2 ) thin films have been explored as a cathode material for reliable glass capacitors. Conducting α-MnO2 thin films were deposited on a borosilicate glass substrate by a chemical solution deposition technique. High carbon activities originated from manganese acetate precursor, (Mn(C2 H3 O2 )2 ·4H2 O) and acetic acid solvent (C2 H4 O2 ), which substantially reduced MnO2 phase stability, and resulted in Mn2 O3 formation at pyrolysis temperature in air. The α-MnO2 structure was stabilized by Ba2+ insertion into a (2 × 2) oxygen tunnel frame to form a hollandite structure. With 15–20 mol% Ba addition, a conducting α-MnO2 thin film was obtained after annealing at 600–650°C, exhibiting low electrical resistivity (∼1 Ω·cm), which enables application as a cathode material for capacitors. The hollandite α-MnO2 phase was stable at 850°C, and thermally reduced to the insulating bixbyte (Mn2 O3 ) phase after annealing at 900°C. The phase transition temperature of Ba containing α-MnO2 was substantially higher than the reported transition temperature for pure MnO2 (∼500°C). 相似文献
10.
SiC films were prepared from the reaction of Si2 H6 with C2 H4 or C2 H2 at relatively low temperatures ranging from 873 K to 1273 K by low-pressure chemical vapor deposition. The deposition rate profiles determined by gravimetry and the alloy composition (carbon content, x, for Si1-x Cx ) profiles determined by X-ray photoemission spectroscopy in the reactor were mainly investigated. The results revealed that the carbon content, x , was a function of the temperature, ratio of partial pressures of source gases, and source gas species (C2 H4 , C2 H2 ). From these results we deduced that SiC formation occurred by two major competing reaction processes: (1) the silicon deposition processes, SiH2 Si (wall) and Si2 H6 Si (wall), and (2) the carbon deposition process, C2 H4 + SiH2 vinylsilane or C2 H2 + SiH2 ethynylsilane. 相似文献
11.
Xia Wang Wei Li Jin-lou Gu Yong-sheng Li Liang Li Jian-lin Shi 《Journal of the American Ceramic Society》2009,92(10):2412-2414
Li2.06 Nb0.18 Ti0.76 O3 powder has been successfully prepared at low temperatures via a facile and manageable, activated pretreatment on the inert raw Nb2 O5 . It is demonstrated that with triethanolamine, citric acid, and hydrogen peroxide, this simple pretreatment process could activate Nb2 O5 efficiently. Pure Li2 TiO3 solid solution phase was thus obtained by calcining the mixture of the activated Nb2 O5 , LiOH·H2 O, and Ti(C4 H9 O)4 at temperatures as low as 650°C, which is about 200°C lower than that of the traditional solid-state method. To the best of our knowledge, this temperature is the lowest one for preparing Li2 TiO3 solid solution. Additionally, the phase transformation and the morphology of the final powder are also discussed. 相似文献
12.
BiScO3 –PbTiO3 (BSPT) thin films near the morphotropic phase boundary were successfully fabricated on Pt(111)/Ti/SiO2 /Si substrates via an aqueous sol–gel method. The thin films exhibited good crystalline quality and dense, uniform microstructures with an average grain size of 50 nm. The dielectric, ferroelectric, and piezoelectric properties of the sol–gel-derived BSPT thin films were investigated. A remanent polarization of 74 μC/cm2 and a coercive field of 177 kV/cm were obtained. The local effective piezoelectric coefficient d * 33 was 23 pC/N at 2 V, measured by a scanning probe microscopy system. The dielectric peak appeared at 435°C, which was 80°C higher than that of Pb(Ti, Zr)O3 thin films. 相似文献
13.
Shin-ichi Hirano Toshinobu Yogo Koichi Kikuta Yasushi Araki Masahiro Saitoh Satoru Ogasahara 《Journal of the American Ceramic Society》1992,75(10):2785-2789
Crack-free Pb(Zr,Ti)O3 (PZT) thin films with preferred orientation were prepared successfully on MgO (100), SrTiO3 (100), and Pt/Ti/SiO2 /Si substrates from metal alkoxide solutions. Calcination of precursor films in a H2 O─-O2 gas mixture was found to be effective not only for low-temperature crystallization of perovskite PZT, but also for obtaining the preferred orientation of PZT films. Single-phase PZT films with high preferred orientation were synthesized on MgO (100) and Pt/Ti/SiO2 /Si substrates at 550° and 600°C for 2 h, respectively. The PZT film on the Pt/Ti/SiO2 /Si substrate showed a permittivity of 520, tan δ of 0.03, a remanent polarization of 24 μC/cm2 , and a coercive field of 54 kV/cm. 相似文献
14.
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
15.
Ian M. Reaney Keith Brooks Radosveta Klissurska Czezlaw Pawlaczyk Nava Setter 《Journal of the American Ceramic Society》1994,77(5):1209-1216
The microstructure and preferred orientations of rapid thermally annealed Pb(Zr0.53 ,Ti0.47 )O3 films, deposited on Pt/Ti/SiO2 /Si electrode/substrates by solution-gel spinning, have been investigated using analytical and high-resolution electron microscopy and X-ray diffraction. The temperature of pyrolysis of the PZT films was found to influence the preferred orientation of the film: lower temperatures (350°C) favored a (111) orientation, whereas higher temperatures (420°C) favored a (100) orientation. Excess Pb was used to control the A-site stoichiometry of the film particularly at the film surface where Pb-deficient crystals could often be observed. The absence of these crystals was shown to be correlated with an improvement in the dielectric response. 相似文献
16.
Novel inorganic–organic membranes that contained Ag+ ions as olefin carriers were prepared using sol–gel and dip-coating processes. The permeance of the membranes for nitrogen, helium, ethane (C2 H6 ), and ethene (C2 H4 ) were evaluated using the single-gas permeation method at temperatures of 298, 373, and 423 K. The results showed that the selectivity of the membranes to C2 H4 against C2 H6 increased as the measurement temperature increased, because the decomplexation rate of C2 H4 molecules from Ag+ sites is enhanced by increases in the temperature. Fourier transform infrared spectrophotometry of the hybrid membranes and the performance of the membranes at 373 and 423 K indicated that poly( N -vinylpyrrolidone) (PVP) had a role in increasing the flexibility of the inorganic network and also served as a mediation agent to fix Ag+ ions in the polymer segments, because of the coordination interaction between the Ag+ ions and the PVP. 相似文献
17.
Hideaki Itoh Hiroshi Asano Keika Fukuroi Makoto Nagata Hiroyasu Iwahara 《Journal of the American Ceramic Society》1997,80(6):1359-1365
A dense Ca(Ti0.75 Fe0.25 )O3−α (Ca(Ti,Fe)O3 ) film, which is a mixed conductor of oxide ions and electrons/holes, was prepared on a porous CaTiO3 substrate by a spin-coating method. The calcined Ca(Ti,Fe)O3 powder with 2–3 μm grain sizes was mixed with a dispersant in ethanol to form the slurry for spin coating. A uniform Ca(Ti,Fe)O3 green film was obtained at 1000–1500 rpm on the rotating porous CaTiO3 substrate, which had an average pore diameter of a few micrometers. The optimum sintering conditions for the spin-coated films were a soaking temperature of 1235°C and a holding time of 2 h, in air. A dense, sintered Ca(Ti,Fe)O3 film }20–50 μm thick was prepared by repeating the coatingsintering process. The gas-tight film prepared on the porous substrate exhibited higher electrochemical permeation of oxygen at an operating temperature of 1000°C compared with that of thicker, sintered Ca(Ti,Fe)O3 disks. 相似文献
18.
Tongjun Liu Zhengguo Jin Jingxia Yang Lirui Feng 《Journal of the American Ceramic Society》2008,91(6):1939-1944
Nanocrystalline SnO2 films were prepared from SnC2 O4 by a sol–gel route. A clarified and stable Sn-containing sol was obtained by dissolving and chelating SnC2 O4 with C6 H8 O7 and H2 C2 O4 in a C6 H8 O7 /triethanolamine (TEA) mixing aqueous solution with a pH of 6.5–7.0. The chelation and condensation reactions were deducted based upon infrared, Raman, and X-ray photoelectron spectra analysis. Results illuminated that a number of ionized-state carboxyl groups and active tin hydrate were produced in the mixing solution by amido association of TEA with H on –COOH of H3 L and H2 C2 O4 , supplying a precondition for tin sol formation. X-ray diffraction and field emission scanning electron microscope analysis indicated that SnO2 film had a rutile structure and consisted of nanocrystals with a mean size of about 7 nm. Film thickness could be controlled by the number of dip coating—annealing cycles according to 30–45 nm/cycle for a Sn concentration of 0.25 mol/L. 相似文献
19.
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
20.
Qifa Zhou Qingqi Zhang Baomin Xu Susan Trolier-McKinstry 《Journal of the American Ceramic Society》2002,85(8):1997-2000
Ferroelectric 0.7Pb(Mg1/3 Nb2/3 )O3 –0.3PbTiO3 (PMN-PT) thin films were deposited on ZrO2 /SiO2 /silicon substrates using a chemical-solution-deposition method. Using a thin PZT film as a seed layer for the PMN-PT films, phase-pure perovskite PMN-PT could be obtained via rapid thermal annealing at 750°C for 60 s. The electrical properties of in-plane polarized thin films were characterized using interdigitated electrode arrays on the film surface. Ferroelectric hysteresis loops are observed with much larger remanent polarizations (∼24 μC/cm2 ) than for through-the-thickness polarized PMN-PT thin films (10–12 μC/cm2 ) deposited on Pt/Ti/Si substrates. For a finger spacing of 20 μm, the piezoelectric voltage sensitivity of in–plane polarized PMN-PT thin films was ∼20 times higher than that of through-the-thickness polarized PMN-PT thin films. 相似文献