Preparation of Pb(Zr1−xTix)O3 powders from complex alkoxide and their lower-temperature crystallization

Pb(ZrxTix)O3 (PZT) powders of 0.2–0.4 μm particle sizes could be obtained from the complex alkoxides synthesized from lead acetate, Zr(OBun)4, and Ti(OEt)4. The powders crystallized to well-crystalline perovskite phases at a temperature as low as 250 °C, independent of the compositional ratio of the B site (Zr/Ti). For the preparation of powders, the complexing of alkoxides, addition of the second solvent such as acetone, acetonitrile, or methyl acetate, and base-catalyzed hydrolysis with ammonia water were essential.

Download Full-text

Surface energy of cellulosic materials: The effect of particle morphology, particle size, and hydroxyl number

TAPPI Journal ◽

10.32964/tj14.9.565 ◽

2015 ◽

Vol 14 (9) ◽

pp. 565-576 ◽

Cited By ~ 1

Author(s):

YUCHENG PENG ◽

DOUGLAS J. GARDNER

Keyword(s):

Particle Size ◽

Surface Energy ◽

Particle Morphology ◽

Nanofibrillated Cellulose ◽

Particle Sizes ◽

Hydroxyl Number ◽

Small Individual ◽

Dispersion Component ◽

Commercial Applications ◽

Lower Temperature

Understanding the surface properties of cellulose materials is important for proper commercial applications. The effect of particle size, particle morphology, and hydroxyl number on the surface energy of three microcrystalline cellulose (MCC) preparations and one nanofibrillated cellulose (NFC) preparation were investigated using inverse gas chromatography at column temperatures ranging from 30ºC to 60ºC. The mean particle sizes for the three MCC samples and the NFC sample were 120.1, 62.3, 13.9, and 9.3 μm. The corresponding dispersion components of surface energy at 30°C were 55.7 ± 0.1, 59.7 ± 1.3, 71.7 ± 1.0, and 57.4 ± 0.3 mJ/m2. MCC samples are agglomerates of small individual cellulose particles. The different particle sizes and morphologies of the three MCC samples resulted in various hydroxyl numbers, which in turn affected their dispersion component of surface energy. Cellulose samples exhibiting a higher hydroxyl number have a higher dispersion component of surface energy. The dispersion component of surface energy of all the cellulose samples decreased linearly with increasing temperature. MCC samples with larger agglomerates had a lower temperature coefficient of dispersion component of surface energy.

Download Full-text

Fractionation trends in the Bay of Islands ophiolite of Newfoundland: polycyclic cumulate sequences in ophiolites and their classification

Canadian Journal of Earth Sciences ◽

10.1139/e77-105 ◽

1977 ◽

Vol 14 (5) ◽

pp. 1156-1165 ◽

Cited By ~ 54

Author(s):

W. R. Church ◽

L. Riccio

Keyword(s):

Basaltic Magma ◽

General Rule ◽

Olivine Gabbro ◽

Lower Velocity ◽

Crystallization Sequence ◽

Basaltic Rocks ◽

Lower Temperature ◽

High Velocity Layer ◽

Velocity Layer ◽

Temperature Crystallization

The fractionation range of the cumulate sequence of the allochthonous Bay of Islands ophiolite of the Western Platform of Newfoundland, measured in terms of the FeO(tolal)/MgO ratios of the liquids from which they were derived, encompasses entirely the range of known values exhibited by the overlying dikes and pillow lavas. Cryptic variations within the cumulate sequences are irregular, often inverse, and the crystallization sequences found in the cumulates suggest that they were formed from at least three different basaltic magma types, one of which is unusual in having given rise to co-existing highly aluminous clinopyroxenes and spinels. These features suggest that crystallization of the Bay of Islands plutonic rocks took place in an 'open system' magma chamber that was tapped repeatedly during fractionation to form dike rocks and lavas. Most of the cumulate rocks of the Bay of Islands ophiolite formed according to the crystallization sequence ol–cpx–(opx) or the sequence ol–plag–cpx–(opx). In contrast, the cumulate rocks of the Betts Cove ophiolite, located within the Fleur de Lys orthotectonic zone of the Newfoundland Appalachians, crystallized according to the sequences ol–opx–cpx and ol–cpx–plag. This difference in the nature of the cumulate sequences within the Bay of Islands and Betts Cove ophiolites is also reflected in the Ti characteristics of the basaltic rocks of the ophiolites, and in the morphology of the gabbroic units. Comparison with Mesozoic ophiolites suggests, as a general rule, that within ophiolite cumulate successions there is a tendency for ol–opx sequences to be followed by ol–cpx sequences, and for ol–cpx sequences to be followed by ol–plag sequences. Such a relationship may be related to processes involving remelting of lower-temperature crystallization products in a system open to either continuous or periodic additions of high temperature basaltic liquid. In terms of oceanic structures the Bay of Islands ophiolite corresponds to sonobouy model 2 of Christensen and Salisbury: the basal high velocity layer corresponding to the olivine-gabbro cumulate rocks, and the lower velocity 'gabbroic' layer to the upper part of the olivine-free cumulate sequence and overlying massive uralitized roof gabbro and dike rocks.

Download Full-text

The Low-Temperature Crystallization and Interface Characteristics of ZnInSnO/In Films Using a Bias-Crystallization Mechanism

Journal of Nanomaterials ◽

10.1155/2012/272387 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

K. J. Chen ◽

F. Y. Hung ◽

T. S. Lui ◽

S. J. Chang ◽

Z. S. Hu

Keyword(s):

Low Temperature ◽

Transparent Conductive Oxide ◽

Crystallization Mechanism ◽

Critical Factors ◽

Interface Characteristics ◽

Short Period ◽

Higher Temperature ◽

Low Temperature Crystallization ◽

Lower Temperature ◽

Temperature Crystallization

This study presents a successful bias crystallization mechanism (BCM) based on an indium/glass substrate and applies it to fabrication of ZnInSnO (ZITO) transparent conductive oxide (TCO) films. The effects of bias-crystallization on electrical and structural properties of ZITO/In structure indicate that the current-induced Joule heating and interface diffusion were critical factors for low-temperature crystallization. With biases of 4 V and 0.1 A, the resistivity of the ZITO film was reduced from3.08×10−4 Ω∗cm to6.3×10−5 Ω∗cm. This reduction was attributed to the bias-induced energy, which caused indium atoms to diffuse into the ZITO matrix. This effectuated crystallizing the amorphous ZITO (a-ZITO) matrix at a lower temperature (approximately170∘C) for a short period (≤20 min) during a bias test. The low-temperature BCM developed for this study obtained an efficient conventional annealed treatment (higher temperature), possessed energy-saving and speed advantages, and can be considered a candidate for application in photoelectric industries.

Download Full-text

Oxygen-Enriched Combustion Characteristics of Lignite: A Case Study of the Pingzhuang Lignite from Inner Mongolia, China

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.550-553.2868 ◽

2012 ◽

Vol 550-553 ◽

pp. 2868-2872

Author(s):

Xiang Yun Chen ◽

Yong Feng Zhang ◽

Qian Cheng Zhang ◽

Jie Bai ◽

Fei Wu

Keyword(s):

Particle Size ◽

Oxygen Concentration ◽

Volume Fraction ◽

Particle Sizes ◽

Temperature Zone ◽

Thermogravimetric Method ◽

Combustion Experiment ◽

Lower Temperature ◽

Lower Temperature Zone

Combustion curves of lignite samples from China in four different particle sizes and Oxygen-enriched condition were analyzed using non-isothermal thermogravimetric method. The lignite samples separated into -150+100 μm, -100+75 μm, -75+50 μm, and -50μm sizes. Combustion profiles shift to lower temperature zone as particle size decrease. Combustion profiles have little difference when the particle size below 100 μm in oxygen atmosphere; Oxygen-enriched combustion experiment were carried out in O2/N2 mixture atmospheres with the volume fraction of oxygen was 21%, 30%, 40%, 50%, 60% and 70%, respectively. As oxygen concentration increase profiles shift to lower temperature zone. and gets the proper range of oxygen concentration is about 50%.

Download Full-text

Low-temperature crystallization induced by excimer laser irradiation of SrBi2Ta2O9 films

Journal of Materials Research ◽

10.1557/jmr.2001.0257 ◽

2001 ◽

Vol 16 (7) ◽

pp. 1883-1886 ◽

Cited By ~ 9

Author(s):

Kwang Soo Seol ◽

Hironao Hiramatsu ◽

Yoshimichi Ohki ◽

In-Hoon Choi ◽

Yong-Tea Kim

Keyword(s):

Low Temperature ◽

Laser Irradiation ◽

Excimer Laser ◽

Precursor Film ◽

Excimer Laser Irradiation ◽

Low Temperature Crystallization ◽

Lower Temperature ◽

Substrate Temperatures ◽

Induced Crystallization ◽

Temperature Crystallization

Transition of a SrBi2Ta2O9 precursor film from amorphous to crystalline was inducedby excimer laser irradiation. Both fluorite and perovskite crystalline structures in suchfilms were obtained by excimer laser irradiation at substrate temperatures between 200and 500 °C. Either an addition of excess bismuth in the precursor film or an increasein the substrate temperature enhanced the formation of the perovskite structure in theexcimer laser-induced annealing process, resulting in the perovskite crystalline phase ata relatively lower temperature of 500 °C. Such a low temperature is preferred whenSrBi2Ta2O9 is used in ferroelectric devices. The mechanism involved in thislaser-induced crystallization is also discussed.

Download Full-text

Lower temperature crystallization and ordering in sol-gel derived Pb(Sc/sub 0.5/Ta/sub 0.5/)O/sub 3/ powders and thin layers

Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics ◽

10.1109/isaf.1994.522395 ◽

2002 ◽

Author(s):

Donhang Liu ◽

D.A. Payne

Keyword(s):

Sol Gel ◽

Thin Layers ◽

Lower Temperature ◽

Temperature Crystallization

Download Full-text

On the Sintering Activation Energy of α-Al2O3

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.686 ◽

2008 ◽

Vol 368-372 ◽

pp. 686-687 ◽

Cited By ~ 1

Author(s):

Wei Quan Shao ◽

Shaou Chen ◽

Da Li ◽

Ping Qi ◽

Yong Wan ◽

...

Keyword(s):

Activation Energy ◽

Particle Size ◽

Temperature Interval ◽

High Purity ◽

Powder Compact ◽

Isothermal Condition ◽

Particle Sizes ◽

Higher Temperature ◽

Lower Temperature ◽

Increasing Temperature

The sintering activation energy of high-purity alumina powders with different particle sizes was evaluated under non-isothermal condition. It was found that, during sintering, the activation energy for the lower temperature stage is higher than that for higher temperature stage. The value of the activation energies for the powder compact with larger particle size was higher than that for the powder compact with smaller particle size. If the selected temperature interval for calculation was narrow enough, the evaluated activation energy values varied with the increasing temperature continuously.

Download Full-text

The Effects of Various Substrate Temperature of Bi2O3 Buffer Layer on SBT (SrBi2Ta2O9) Thin Films Deposited by R.F. Magnetron Sputtering

Materials Science Forum ◽

10.4028/www.scientific.net/msf.569.137 ◽

2008 ◽

Vol 569 ◽

pp. 137-140

Author(s):

Ji Eon Yoon ◽

Won Hyo Cha ◽

Dong Hyun Hwang ◽

Chul Su Lee ◽

In Seok Lee ◽

...

Keyword(s):

Thin Films ◽

Magnetron Sputtering ◽

Substrate Temperature ◽

Buffer Layer ◽

Ferroelectric Properties ◽

Secondary Phases ◽

X Ray Diffraction ◽

X Ray ◽

Lower Temperature ◽

Temperature Crystallization

The SBT(SrBi2Ta2O9) thin films with Bi2O3 buffer layer were deposited on Pt/Ti/SiO2/Si substrate by R.F. magnetron sputtering method in order to improve the ferroelectric characteristics. In SBT thin films, the deficiency of bismuth due to its volatility during the process results in an obvious non stoichiometry of the films and the presence of secondary phases. Bi2O3 buffer layer was found to be effective to achieve lower temperature crystallization and improve ferroelectric properties of SBT thin films. Ferroelectric properties and crystallinities of SBT thin films with various substrate temperature of Bi2O3 buffer layer were observed, using X-Ray Diffraction (XRD), Precision LC (Radient Technologies. Inc.) and GDS (glow discharge spectrometer).

Download Full-text

Comparative analysis of the performance of mixing rules for density prediction of simple chemical mixtures

Journal of Engineering Sciences ◽

10.21272/jes.2021.8(1).f4 ◽

2021 ◽

Vol 8 (1) ◽

pp. F25-F31

Author(s):

F.U. Babalola ◽

I.O. Akanji ◽

T. Oyegoke

Keyword(s):

Methyl Acetate ◽

Van Der Waals ◽

Water System ◽

Intermolecular Forces ◽

Attractive Force ◽

Mixing Rules ◽

Force Parameter ◽

Ammonia Water ◽

Mixture Densities ◽

Density Prediction

Four different mixing rules (MRs) in three equations of state (EOSs) have been used to account for the intermolecular forces of attraction between dissimilar molecules of different substances that form simple mixtures. The combined effects of the co-volumes of all constituent species of the mixtures were also considered, and the densities of these simple mixtures were predicted. Thereafter, the density results obtained were compared with accurately simulated experimental density values, and the effectiveness of these MRs was determined and compared. The four MRs compared are geometric mean average (GMA), whole square root average (SRA), Expanded geometric average (EGA), and simple average (SA) of attractive force parameter. They were all used in Van der Waals, Redlich Kwong, and Peng Robinson EOSs for two simple mixtures: a binary system (Ammonia – Water system) and a ternary mixture (methyl acetate – water – toluene system). It was found that GMA and EGA gave reasonably accurate estimates of the mixture attractive force parameter (am) and hence good density prediction for both Ammonia – Water and Methyl acetate – Water – Toluene systems. SRA gave unrealistic values of mixture densities for both systems and was discarded. SA gave a somewhat good result with Peng Robinson EOS for the ammonia-water system, but not that good in Redlich Kwong EOS and very poor in Van der Waals EOS. SA does not give reasonable estimates of the mixture densities with the three EOSs considered for the methyl acetate – water – toluene system.

Download Full-text