Effect of Hydrothermal Process on Xonotlite Crystal

2011 ◽  
Vol 382 ◽  
pp. 379-383 ◽  
Author(s):  
Fei Liu ◽  
Xiao Dan Wang ◽  
Jian Xin Cao
Keyword(s):  
Phase Composition ◽  
Aspect Ratio ◽  
Spherical Particle ◽  
Hydrothermal Process ◽  
Crystal Phase

Effect of hydrothermal process on xonotlite crystal prepared from K2SiO3 and H2SiO3 respectively in CaO-SiO2-H2O system was researched in this paper. The crystal phase composition and morphology of the xonotlite crystal were analyzed using XRD and techniques. The results indicate that different hydrothermal process poses significant impact on the microstructure of xonotlite crystal. The xonotlite spherical particle with the diameter of 10-20 µm was prepared from H2SiO3 only via dynamic hydrothermal process. The xonotlite whisker prepared from K2SiO3 with the length of 20-40 μm, diameter of 400 nm and the aspect ratio of 50-100 was successfully prepared from K2SiO3 via dynamic hydrothermal process, while with the length of 5-10 μm, diameter of 500 nm and the aspect ratio of 10-20 via static hydrothermal process.

Effect of Anion Impurity on Preparing Xonotlite Whiskers via Hydrothermal Synthesis

2010 ◽  
Vol 148-149 ◽  
pp. 1755-1758 ◽  
Author(s):  
Fei Liu ◽  
Jian Xin Cao ◽  
Bo Zhu
Keyword(s):  
Phase Composition ◽  
Hydrothermal Synthesis ◽  
Aspect Ratio ◽  
Hydrothermal Process ◽  
Process Condition ◽  
Crystal Phase ◽  
Reactant Concentration ◽  
Calcium Sources ◽  
Anion Impurity

Effect of anion impurity on preparing xonotlite whiskers via hydrothermal synthesis was researched in this paper. The crystal phase composition and morphology of the xonotlite whiskers were analyzed using XRD and techniques. The results indicate that different anion impurity have little effect on the crystal phase composition of synthesized the products, but have great impact on the crystallinity and morphology of xonotlite whiskers. Xonotlite whiskers with well crystal and aspect ratio of 50-100 were successfully prepared from CaCl2 as calcium sources under the condition of 225 °C for 15 h with the reactant concentration of 0.05mol•L-1, but the hydrothermal process condition should be controlled at 225 °C for 40 h while using Ca(NO3)2 or Ca(OH)2 as calcium sources. Cl- iron can accelerate the process of hydrothermal synthesis and be beneficial to the crystallization of xonotlite in CaO-SiO2-H2O system.

The study of crystal-phase composition and pore structure for Dicaoqing-Zisha compared with porcelain and pottery

2020 ◽  
Author(s):  
Chunrui Yang ◽  
Jianyi Kong ◽  
Jiajing Yang ◽  
Chengliang Chu ◽  
Xingdong Wang ◽  
...  
Keyword(s):  
Phase Composition ◽  
Pore Structure ◽  
Crystal Phase

Optimization of Active Sites via Crystal Phase, Composition, and Morphology for Efficient Low‐Iridium Oxygen Evolution Catalysts

2020 ◽  
Vol 59 (44) ◽  
pp. 19654-19658 ◽  
Author(s):  
Hui Chen ◽  
Lei Shi ◽  
Xiao Liang ◽  
Lina Wang ◽  
Tewodros Asefa ◽  
...  
Keyword(s):  
Phase Composition ◽  
Oxygen Evolution ◽  
Active Sites ◽  
Crystal Phase

Mechanism of Synthesizing Al2O3/Fe-Al Composites with Nano Al2O3 Fibers by In Situ Process

2013 ◽  
Vol 562-565 ◽  
pp. 837-841
Author(s):  
Chen Jing Lu ◽  
Shu Xia Ren ◽  
Jian Lei Wang ◽  
Gang Yu
Keyword(s):  
Phase Composition ◽  
Elemental Composition ◽  
Partial Oxidation ◽  
Aluminum Content ◽  
Sintering Temperature ◽  
Crystal Phase ◽  
In Situ Composite ◽  
Al Content ◽  
Crystal Composition

In-situ composite of Al2O3/Fe-Al with Al2O3 fibers were prepared by partial oxidation of oxygen to Fe powder and Al power, crystal phase composition and elemental composition were analyzed by XRD, NORAN. The results indicated that, the crystal composition is determined by Aluminum content, when the content is enough, FeAl3, Al and Al2O3 will be gain, on the contrary, Fe2Al, FeAl, Fe3Al and Al2O3 will be gain; Al2O3 fibers were synthesized via VLS process, the quantity of Al2O3 fibers increased with the Al content, the whisker’s diameter was improved with increasing of sintering temperature.

Control of the Crystal Phase Composition of FexOy Nanopowders Prepared by CO2 Laser Vaporization

2013 ◽  
Vol 13 (11) ◽  
pp. 4868-4876 ◽  
Author(s):  
Christian Stötzel ◽  
Heinz-Dieter Kurland ◽  
Janet Grabow ◽  
Silvio Dutz ◽  
Eberhard Müller ◽  
...  
Keyword(s):  
Phase Composition ◽  
Co2 Laser ◽  
Crystal Phase ◽  
Laser Vaporization

Fabrication of Highly Flexible Copper Nanowires in Dual Surfactant Hydrothermal Process

2019 ◽  
Vol 19 (11) ◽  
pp. 7156-7162 ◽  
Author(s):  
Mary Donnabelle L. Balela ◽  
Salvacion B. Orgen ◽  
Michael R. Tan
Keyword(s):  
Phase Composition ◽  
Reaction Time ◽  
Intermediate Phase ◽  
Hydrothermal Process ◽  
Optical Transmittance ◽  
The Other ◽  
Copper Nanowires ◽  
Cu Nanowires ◽  
Mean Diameter ◽  
Ag Nanowires

Highly flexible Cu nanowires were successfully synthesized by a dual-surfactant hydrothermal process using oleylamine and oleic acid. The ultra-long Cu nanowires have a mean diameter as low as 82.3 nm and lengths greater than 300 μm. It was found that reaction time and oleylamine concentration significantly influenced the morphology and phase composition of the Cu products. At a shorter reaction time (about 4 hours), pentagonal bipyramidal CU2O particles were precipitated together with the Cu nanowires. A longer reaction time of 12 hours resulted in smooth and purely metallic Cu nanowires. It is possible that CU2O served as an intermediate phase to control the activity of free CU2+ ions in the solution. On the other hand, a higher oleylamine concentration generally produced longer Cu nanowires. Cu nanowires conducting electrode with a sheet resistance of about 157.0 Ω/□ were fabricated. However, the optical transmittance of the electrode at 550 nm was very low (<20%) because of the agglomeration of the Cu nanowires. The addition of a small quantity of Ag nanowires in the Cu nanowire ink markedly improved the appearance and electrical properties of the resulting electrode.

scholarly journals Influence of Different Solvents and High-Electric-Field Cycling on Morphology and Ferroelectric Behavior of Poly(Vinylidene Fluoride-Hexafluoropropylene) Films

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3884
Author(s):  
Till Mälzer ◽  
Lena Mathies ◽  
Tino Band ◽  
Robert Gorgas ◽  
Hartmut S. Leipner
Keyword(s):  
Phase Composition ◽  
Electric Field ◽  
Surface Structure ◽  
Electric Fields ◽  
Vinylidene Fluoride ◽  
High Electric Field ◽  
Crystal Phase ◽  
Shielding Effect ◽  
Ferroelectric Behavior ◽  
Field Cycling

P(VdF-HFP) films are fabricated via a solution casting doctor blade method using high (HVS) and low (LVS) volatile solvents, respectively. The structural properties and the ferroelectric behavior are investigated. The surface structure and crystal phase composition are found to be strongly dependent on the type of solvent. LVS leads to a rougher copolymer surface structure with large spherulites and a lower crystallinity in contrast with HVS. The crystalline phase of copolymer films fabricated with HVS consists almost exclusively of α-phase domains, whereas films from LVS solution show a large proportion of γ-phase domains, as concluded from Raman and X-ray diffraction spectra. Virgin films show no ferroelectric (FE) switching polarization at electric field amplitudes below 180 MV/m, independent of the solvent type, observed in bipolar dielectric displacement—electric field measurements. After applying electric fields of above 180 MV/m, a FE behavior emerges, which is significantly stronger for LVS films. In a repeated measurement, FE polarization switching already occurs at lower fields. A shielding effect may be related to this observation. Additionally, Raman bands of polar γ-phase increase by high-electric-field cycling for the LVS sample. The solvent used and the resulting crystal phase composition of the virgin sample is crucial for the copolymer behavior during bipolar electrical cycling.

scholarly journals Effects of Si/Al Ratios on the Bulk-Type Zeolite Formation Using Synthetic Metakaolin-Based Geopolymer with Designated Composition

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1310
Author(s):  
Guoru Ma ◽  
Chengying Bai ◽  
Meirong Wang ◽  
Peigang He
Keyword(s):  
Phase Composition ◽  
Hydrothermal Treatment ◽  
Hydrothermal Process ◽  
Molar Ratios ◽  
Zeolite Formation ◽  
Fixed Composition ◽  
Type Zeolite ◽  
Influence Of Impurities ◽  
Geopolymer Composites

In this paper, synthetic metakaolin with fixed composition (Al2O3·2SiO2) was produced by a simple chemosynthetic route. The chemosynthetic metakaolin can eliminate the influence of impurities in metakaolin from natural kaolin minerals. The synthetic metakaolin together with NaOH and SiO2-sol were used to prepare Na-based geopolymer precursors with various molar ratios of Si/Al. The molar ratios of Si/Al from 1 to 2 were tailored by adding different contents of SiO2-sol. Zeolite/geopolymer composites or monolith-type zeolite were successfully fabricated from synthetic metakaolin-based geopolymer through a hydrothermal process. The effects of Si/Al ratios on the phase composition and microstructure of the produced zeolite/geopolymer composites or zeolites were studied. The results proved that the composition of synthetic metakaolin and geopolymer precursors can be facilely tuned, and the monolithic geopolymer precursors can be mostly, or even totally, transformed into zeolite after hydrothermal treatment.

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