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Статті в журналах з теми "Sol-gel composition"
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Ali, A. F., P. Mustarelli, E. Quartarone, C. Tomasi, P. Baldini, and A. Magistris. "Sol-gel Lithium Borophosphates." Journal of Materials Research 14, no. 4 (April 1999): 1510–15. http://dx.doi.org/10.1557/jmr.1999.0202.
Повний текст джерелаАнотація:
In this paper we present sol-gel synthesis and thermal and structural characterization of some lithium borophosphates. The as-prepared samples are mostly partially crystalline, and densification heat treatments at 500 °C cause samples to crystallize. In the phosphorus-rich part of the composition triangle we have lithium excess with respect to the nominal composition, which is likely due to the low reactivity of the phosphorus precursor. On the boron-rich side, in contrast, lithium losses are found which probably occur during syneresis.
2
Miao, Hong Yan, Jing Yun Ma, and Guo Qiang Tan. "Preparation of Barium Strontium Titanate Nanopowders by a Sol-Gel Hydrothermal Synthesis Method." Key Engineering Materials 368-372 (February 2008): 50–52. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.50.
Повний текст джерелаАнотація:
Barium strontium titanate, BST (BaxSr1-xTiO3), nanoparticles were prepared by a sol-gel hydrothermal technique. BST powders of different composition (x=0.1, x=0.3, x= 0.5, x=0.7, x=0.9) prepared by sol-gel technique previously were treated by hydrothermal synthesis method later. XRD results indicated that the as-prepared perovskite BST nanoparticles have the accurate proportioning composition. These results showed that the combination of sol-gel and hydrothermal technique would become a potential and promising process for fabricating BST and other nanopowders.
3
Chatzistavrou, Xanthippi, E. Hatzistavrou, Nikolaos Kantiranis, Lambrini Papadopoulou, Eleana Kontonasaki, K. Chrissafis, Petros Koidis, Konstantinos M. Paraskevopoulos, and Aldo Roberto Boccaccini. "Novel Glass-Ceramics for Dental Application by Sol Gel Technique." Key Engineering Materials 396-398 (October 2008): 153–56. http://dx.doi.org/10.4028/www.scientific.net/kem.396-398.153.
Повний текст джерелаАнотація:
The aim of this study was the fabrication using a sol-gel technique of a new glass-ceramic with potential use in dental applications. The characterization of the composition and microstructural properties of the produced material confirmed the similarity between the new sol-gel derived glass-ceramic and a commercial leucite based fluorapatite dental glass-ceramic. The produced material has potential application in dental restorations and it is expected to exhibit better control of composition, microstructure and properties due to the intrinsic advantages of the sol-gel preparation method.
4
Wang, Xu, Bao Xiang Jiao, Xia Zhang, Ju Hua Luo, and Hao Guan. "Sol-Gel Preparation and Infrared Radiation Property of Zinc-Substituted Cordierite Ceramics." Advanced Materials Research 652-654 (January 2013): 316–20. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.316.
Повний текст джерелаАнотація:
The sol-gel process is a useful technique with good control over final amount of compositions which can decrease the temperature of sintering in the melting procedure. A cordierite infrared radiation ceramic with a nominal composition of Mg2(1-x)Zn2xAl4Si5O18（x=0、0.05、0.10、0.15、0.20）was prepared using the powders by sol-gel method and heat treatment at 1523K for 2 hours. The results indicate that the sol-gel method can effectively decrease the sintered temperature and the substitution of Zn2+ to Mg2+ can let structural change and improve the infrared radiation properties. The specimen of x=0.20 attained a relatively high infrared emissivity of 0.91 in the whole band.
5
Sooksaen, Pat. "Morphology and Phase Composition of Sol-Gel Derived Aluminum Borate Nanowhiskers." Key Engineering Materials 659 (August 2015): 121–26. http://dx.doi.org/10.4028/www.scientific.net/kem.659.121.
Повний текст джерелаАнотація:
Aluminium borate nanowhiskers with varying aspect ratio were synthesized via sol–gel synthesis. The morphology of aluminum borate (Al4B2O9 and Al18B4O33) nanowhiskers could be controlled by varying the aluminum to boron (Al:B) molar ratio in the sol–gel derived precursors. Sintering temperatures (850 and 1100°C) and sintering times (4 and 32 hours) also affected the phase composition and size of the nanowhiskers. Citric acid was also added in the sol–gel derived precursors as a surface stabilizer for obtaining uniform finely dispersed nanostructures. Fine nanowhiskers were obtained by the calcination at 850°C, whereas higher temperature of 1100°C led to thicker and longer nanowhiskers and became rod-like crystals. The morphology and phase composition were investigated by field emission scanning electron microscope and X-ray diffraction. Chemical bond vibrations in the synthesized nanowhiskers were investigated by Fourier-transform infrared spectroscopy.
6
Kolchanov, Denis S., Vladislav Slabov, Kirill Keller, Ekaterina Sergeeva, Mikhail V. Zhukov, Andrey S. Drozdov, and Alexandr V. Vinogradov. "Sol–gel magnetite inks for inkjet printing." Journal of Materials Chemistry C 7, no. 21 (2019): 6426–32. http://dx.doi.org/10.1039/c9tc00311h.
Повний текст джерелаАнотація:
The article describes an easy-to-implement and print-ready composition for inkjet printing of magnetic structures, which can be used for security printing, coding, and marking, magnetic device fabrication or creation of micro-antennas.
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Bokov, Dmitry, Abduladheem Turki Jalil, Supat Chupradit, Wanich Suksatan, Mohammad Javed Ansari, Iman H. Shewael, Gabdrakhman H. Valiev, and Ehsan Kianfar. "Nanomaterial by Sol-Gel Method: Synthesis and Application." Advances in Materials Science and Engineering 2021 (December 24, 2021): 1–21. http://dx.doi.org/10.1155/2021/5102014.
Повний текст джерелаАнотація:
The sol-gel process is a more chemical method (wet chemical method) for the synthesis of various nanostructures, especially metal oxide nanoparticles. In this method, the molecular precursor (usually metal alkoxide) is dissolved in water or alcohol and converted to gel by heating and stirring by hydrolysis/alcoholysis. Since the gel obtained from the hydrolysis/alcoholysis process is wet or damp, it should be dried using appropriate methods depending on the desired properties and application of the gel. For example, if it is an alcoholic solution, the drying process is done by burning alcohol. After the drying stage, the produced gels are powdered and then calcined. The sol-gel method is a cost-effective method and due to the low reaction temperature there is good control over the chemical composition of the products. The sol-gel method can be used in the process of making ceramics as a molding material and can be used as an intermediate between thin films of metal oxides in various applications. The materials obtained from the sol-gel method are used in various optical, electronic, energy, surface engineering, biosensors, and pharmaceutical and separation technologies (such as chromatography). The sol-gel method is a conventional and industrial method for the synthesis of nanoparticles with different chemical composition. The basis of the sol-gel method is the production of a homogeneous sol from the precursors and its conversion into a gel. The solvent in the gel is then removed from the gel structure and the remaining gel is dried. The properties of the dried gel depend significantly on the drying method. In other words, the “removing solvent method” is selected according to the application in which the gel will be used. Dried gels in various ways are used in industries such as surface coating, building insulation, and the production of special clothing. It is worth mentioning that, by grinding the gel by special mills, it is possible to achieve nanoparticles.
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Liu, Hsue-Yang, Steven C. Switalski, Bradley K. Coltrain, and Paul B. Merkel. "Oxygen Permeability of Sol-Gel Coatings." Applied Spectroscopy 46, no. 8 (August 1992): 1266–72. http://dx.doi.org/10.1366/0003702924123881.
Повний текст джерелаАнотація:
Sol-gel processes are applied to prepare organic-inorganic composite coatings. The purpose of this report is to evaluate the possibility of tuning the oxygen permeability of the resulting coatings. It is proposed that if the oxygen permeability is largely controlled by the hydrophobic character and the pore sizes of membranes, then the permeability of the solgel coatings could be tuned by adjusting the composition of the organosilane precursor. The oxygen permeability is measured by the selective oxygen quenching of phosphorescent probes, such as platinum octaethylporphine (PtOEP). The application of such sol-gel coatings for optical fiber oxygen sensors will also be discussed.
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Taib, Taifunisyam, Souad A. Mohamad, Mohd Rafie bin Johan, Wan Jefrey Basiron, Chin Kim Ming, Chia Chang Cherng, and Tan Jia Herng. "Optical, Thermal and Dielectric Studies of Silver-Silica Nanoparticles Synthesized via Sol-Gel Technique." Materials Science Forum 846 (March 2016): 318–25. http://dx.doi.org/10.4028/www.scientific.net/msf.846.318.
Повний текст джерелаАнотація:
Silver-silica nanocomposites (Ag-SiO2NCs) with various compositions were synthesized through sol-gel technique. The morphology, optical and thermal stability of the nanocomposite were investigated and was compared with pure sol-gel to determine the effects of the nanoparticles. Transmission electron microscopy (TEM) confirmed that SiO2 was encapsulated Ag with mean size of 30 nm. Uv-vis spectroscopy shows that the surface plasmon resonance (SPR) peak show Ag-SiO2 NCs were greatly reduce due to the SiO2 particles. The permittivity and refractive index were decreased as the composition of Ag was increased at composition of 60% silver. The real permittivity is negative along the visible region. The trend stability of Ag-SiO2NCs were increased with the increased amount of silver.
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Tiwari, Atul. "A topical review on hybrid quasi-ceramic coatings for corrosion protection." Corrosion Reviews 36, no. 2 (April 25, 2018): 117–25. http://dx.doi.org/10.1515/corrrev-2017-0008.
Повний текст джерелаАнотація:
AbstractA set of unique properties can be derived by a proper combination of organic and inorganic segments in a coating composition. The synthesis of such hybrid coatings is a challenging task due to that a number of variable parameters need to be optimized to achieve the desired results. Similar to the copolymerization of macromolecular segments in a common solvent, sol–gel chemistry could provide a viable alternate for the development of single-phase coating composition. The coating derived through sol–gel and wet chemistry displays homogenous physical and chemical characteristics. A large variety of chemical moieties containing labile functional groups are available for the development of new coating compositions. This article briefly reviews such studies that are reported in majority of the academic sector.
Дисертації з теми "Sol-gel composition"
1
Holtzinger, Claire. "Effets de composition et de morphologie sur la mouillabilité de revêtements sol-gel nanocomposites." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00961171.
Повний текст джерелаАнотація:
Des revêtements sol-gel nanocomposites TiO2-SiO2 ont été réalisés à partir de mélanges d'une suspension nanocristalline de TiO2 anatase et de sols polymériques de silice. Ces revêtements présentent une superhydrophilie naturelle, persistante et photo-régénérable. La présence de charges localisées aux interfaces granulaires TiO2-SiO2 est une des hypothèses permettant d'expliquer cette superhydrophilie naturelle. Toutefois des effets de morphologie (rugosité, porosité de surface) sont également connus pour influencer le mouillage. Des études ont été menées pour mettre directement en évidence l'effet intrinsèque des interfaces granulaires. Les études se sont recentrées sur l'effet extrinsèque de paramètres morphologiques susceptibles d'influencer la mouillabilité des revêtements nanocomposites selon des modèles thermodynamiques des surfaces connus. De nouveaux protocoles de synthèse par voie sol-gel ont été mis au point afin d'analyser i/ en quoi la superhydrophilie naturelle et photo-induite des revêtements TiO2-SiO2 pouvait être influencée par des effets de morphologie et de composition, et ii/ en quoi une exacerbation de ces effets via des structurations artificielles pouvaient encore accroître la superhydrophile de surface. Une extrapolation de ces protocoles a également permis d'étudier des revêtements superhydrophobes.
2
Younis, Ahmed. "Protection of Aluminum Alloy (AA7075) from Corrosion by Sol-Gel Technique." Doctoral thesis, Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-83230.
Повний текст джерелаАнотація:
Die vorliegende Arbeit beschäftigt sich mit der Entwicklung von Sol-Gel-Beschichtungen durch Optimierung der Ausgangszusammensetzung und der Applikations-Parameter für den Korrosionsschutz der Aluminium-Legierung AA7075. Verschiedene Arten von Silanen, z. B. Tetraethoxysilan (TEOS), Phenyltriethoxysilan (PTES) und Phenyltrimethoxysilan (PTMS) sind verglichen worden: Der Sol-Gel-Film aus PTMS präpariert, weist dabei die höchste Hydrophobizität auf, was sich insbesondere in den Barriere-Eigenschaften dieser Verbindung zeigte. Die Wirkung von Essigsäure als Katalysator in Sol-Gel-Prozessen wurden untersucht, um die optimale Katalysatorkonzentration für den Korrosionsschutz der beschichteten Proben zu ermitteln. Die Korrosionsbeständigkeit der beschichteten Proben sinkt bei höheren Konzentrationen des sauren Katalysators durch die Auflösung des Aluminiumoxids an der Substratoberfläche. Allerdings führten zu niedrige Konzentrationen des Katalysators zur Verlangsamung der Hydrolysereaktionen der Silane und es bildete sich poröse Sol-Gel-Schichten. Die Wärmebehandlung der beschichteten Aluminium-Proben ist für die Vernetzung des Films erforderlich. Eine Wärmebehandlung bei 300 ˚C für 2,5 Stunden ergab dabei den besten Korrosionsschutz. Höhere Temperaturen führten zu einer Verschlechterung der Eigenschaften der Filme, was mit der Zerstörung des organischen Teil des Films erklärt werden kann. Darüber hinaus verursachen zu niedrige Temperaturen einen geringeren Korrosionsschutz der beschichteten Aluminium-Proben. Vermutlich ist die geringe Vernetzung des Sol-Gel-Films bei Temperaturen was für als 300 ˚C verantwortlich. Die beschichteten Aluminium-Proben wuden mittels Raster-Elektronenmikroskopie (SEM), Energiedispersive Röntgenspektroskopie (EDX), Röntgen-Photoelektronenspektroskopie (XPS) und elektrochemischen Techniken charakterisiertThe present work pertains to the development of sol-gel coatings by optimizing the composition and the application parameters for corrosion protection of aluminum alloy AA7075. Different kinds of silanes e.g. tetraethoxysilane (TEOS), phenyltriethoxysilane (PTES) and phenyltrimethoxysilane (PTMS) have been compared: the sol-gel film prepared from PTMS shows highest hydrophobicity manifested by the best barrier property of this compound. The effect of acetic acid as a catalyst on the chemistry of the sol is investigated in order to estimate the best catalyst concentration for better corrosion protection of the coated samples. The corrosion resistance of the coated samples is found to be decreasing at higher concentrations of the catalyst due to the dissolution of the aluminum oxide at the substrate surface in the acid sol. However, lower concentrations of the catalyst lead to low hydrolysis reactions of the silanes and non-dense sol-gel films have been formed. The heat treatment of the coated aluminum samples is required for cross-linking of the film. The heat treatment at 300 ˚C for 2.5 hours exhibits the best corrosion protection. Higher treatment-temperatures lead to degradation of the properties of the film which can be described in terms of destroying the organic part of the film. Moreover, low treatment-temperatures cause low corrosion protection of the coated aluminum samples which is presumably attributed to the low cross-linking of the sol-gel film at temperatures less than 300 ˚C. The coated aluminum samples are characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques
3
Muller, Guillaume. "Conception, élaboration et caractérisation de matériaux de composition et de microstructure innovants pour les micro-piles à combustible à oxyde solide." Paris 6, 2012. http://www.theses.fr/2012PA066530.
Повний текст джерелаАнотація:
Les micro-piles à combustible à oxyde solide (micro-SOFC) apparaissent comme des sources d’énergie miniatures attractives et constituent une réelle rupture technologique permettant une solution alternative aux accumulateurs Li-ion actuels. Dans ce contexte, ce travail concerne la synthèse, la caractérisation structurale, microstructurale et électrochimique de films minces denses et poreux de composition et de structure variées : LSCF-CGO, Ni(O)-CGO et CGO. Ces matériaux ont été intégrés comme cathode, anode et électrolyte respectivement dans un dispositif type micro-SOFC fonctionnant vers 400-600°C à partir de H2 comme carburant. L’architecture de la cellule et son procédé de synthèse diffèrent de ceux proposés dans la littérature. En effet, des gradients de porosité et de composition ont été réalisés aux électrodes de manière à limiter les phénomènes de polarisation d’activation et de concentration. De plus, le choix du procédé de synthèse, sol-gel couplé à la méthode de trempage-retrait pour la mise en forme des matériaux, a été guidé par des critères économiques et de facilité de mise en œuvre. Pour la synthèse des films minces denses d’électrolyte (CGO), une autre méthode de synthèse (ALD) a également été utilisée. Dans ce travail, nous avons étudié plus particulièrement les relations qu’il existe entre les propriétés structurale, microstructurale et électrique des films minces poreux d’électrodes, dans les conditions de synthèse et de fonctionnement in fine de la cellule. Sur la base de cette étude, la fabrication et l’évaluation des propriétés électriques de ces micro-SOFC déposées sur un support poreux de Pt/Al2O3 ont été réaliséesThe micro-solid oxide fuel cells (micro-SOFC) appear as attractive miniature sources of energy and are a technological breaking for an alternative to current Li-ion batteries. This work deals with the synthesis, the structural characterization, microstructural and electrochemical of dense and porous thin film exhibiting various composition and structure: LSCF-CGO, Ni(O)-CGO and CGO. These materials have been incorporated as cathode, anode and electrolyte respectively in a device type micro-SOFC operating at 400-600°C with H2 as fuel. The architecture of the cell and the synthesis approach differ from those proposed in the literature. In fact, porosity and composition gradients have been included to the electrodes to limit activation and concentration polarizations. Moreover, the choice of the method of synthesis, sol-gel method coupled with dip-coating to deposit materials was guided by economic criteria and ease implementation. For the synthesis of dense electrolyte thin films (CGO), another synthesis method (ALD) was also explored. In this work, we studied the relationships between structural, microstructural and electrical properties of porous thin film electrodes under the conditions of synthesis and of testing. Based on this study, the fabrication and evaluation of micro-SOFC cells properties deposited on a porous Pt/Al2O3 support have been performed
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Degioanni, Simon. "Nanostructures métalliques et effets de composition des verres silicatés pour les capteurs à fibres optiques." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10101/document.
Повний текст джерелаАнотація:
L'objectif de cette thèse est d'étudier des variations de composition de verres ou l'intégration de nanostructures métalliques pouvant présenter un intérêt pour les capteurs à fibres optiques répartis (CFO). Ces capteurs utilisent le coeur des fibres optiques constitué majoritairement de silice (SiO2) pour sonder la température ou les déformations sur des parcours plurikilométriques de fibres. A cette fin, les rétrodiffusions Raman et Brillouin dans les fibres optiques sont utilisées, la diffusion Raman étant sensible aux variations de température et la diffusion Brillouin aux variations de température et de déformation. L'intensité de diffusion Raman peut-être exaltée au contact de nanostructures de métaux nobles, par l'intermédiaire de l'effet SERS (Diffusion Raman Exaltée de Surface) faisant intervenir notamment la résonance plasmon de surface (SPR), oscillation collective des électrons libres à la surface métallique générant une large amplification du champ électrique local. L'intégration de nanostructures métalliques dans les fibres optiques pourrait permettre d'augmenter l'intensité de rétrodiffusion Raman et améliorer les performances des CFO (sensibilité, temps d'intégration…). Une étude sur des échantillons modèles, constitués de substrats SERS nanostructurés d'or et recouvert de silice par dépôt sol-gel, est présentée dans ce manuscrit. Les résultats SERS ainsi obtenus permettent de caractériser le phénomène physique du SERS de SiO2 et de prédire sa potentielle utilité dans les CFO RamanThe purpose of this thesis is to study composition variations of silicate glasses or the integration of metallic nanostructures that may be relevant for distributed fiber optic sensors (FOS). These sensors use optical fiber cores mainly composed of silica (SiO2) to probe temperature or strain on multi-kilometer route fibers. To measure these effects, Raman and Brillouin backscattering in optical fibers are used, Raman scattering being sensitive to temperature variations and Brillouin scattering to temperature and strain variations. Raman scattering intensity may be enhanced in conjunction with noble metal nanostructures via the SERS effect (Surface Enhanced Raman Scattering) which involves surface plasmon resonance (SPR), a collective oscillation of free electrons at the metal surface generating a large amplification of the local electric field. The integration of metallic nanostructures in optical fibers could increase Raman backscattering intensity and improve FOS performance (sensitivity, integration time…). A study on model samples has been performed with SERS substrates consisting of gold nanostructures and coated with a sol-gel oxide deposition (TiO2, SiO2). The obtained SERS results are used to predict the contribution of metallic nanostructures in Raman distributed temperature FOS
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Chateau, Denis. "Etude de l'influence de la structure et de la composition de matériaux hybrides monolithiques sur les propriétés optiques (luminescence et absorption non-linéaire)." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2013. http://tel.archives-ouvertes.fr/tel-00863807.
Повний текст джерелаАнотація:
Le procédé sol-gel permet la réalisation de matériaux optiquement performants et la possibilité d'intégrer diverses molécules dans ces systèmes ouvre les portes à des applications dans de nombreux domaines. Nous nous sommes intéressés en particulier à la réalisation de matériaux sol-gel monolithiques, fortement dopés avec des molécules actives, dans le cadre de la réalisation de limiteurs optiques performants dans le visible et dans l'infrarouge.La mise au point de procédés et de matrices sol-gel compatibles avec divers types de chromophores a tout d'abord été effectuée. Une investigation des paramètres expérimentaux et de la nature des précurseurs influençant la microstructure des matériaux a été réalisée, ainsi que la mise au point de méthodes de gélification accélérée capables de piéger efficacement les chromophores dans les matrices sol-gel même à de très hautes concentrations.Le dopage des matrices obtenues avec différents chromophores pour la limitation optique dans le visible et dans l'infrarouge s'en est suivi, avec une étude de l'impact des matrices sur les propriétés optiques des dopants. L'évaluation des performances en limitation a révélé les performances exceptionnelles des systèmes étudiés dans le visible, et des résultats prometteurs pour l'infrarouge.Enfin, la synthèse de nanoparticules d'or isotropes et anisotropes et leur incorporation dans les matériaux préparés a permis de mettre en évidence des effets d'exaltation importants sur les propriétés non-linéaires des chromophores au sein des matrices sol-gel et permettent d'améliorer les performances en limitation de manière considérable.
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Müller, Guillaume. "Conception, élaboration et caractérisation de matériaux de composition et de microstructure innovants pour les micro-piles à combustible à oxyde solide." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00833281.
Повний текст джерелаАнотація:
Les micro-piles à combustible à oxyde solide (micro-SOFC) apparaissent comme des sources d'énergie miniatures attractives et constituent une réelle rupture technologique permettant une solution alternative aux accumulateurs Li-ion actuels. Dans ce contexte, ce travail concerne la synthèse, la caractérisation structurale, microstructurale et électrochimique de films minces denses et poreux de composition et de structure variées : LSCF-CGO, Ni(O)-CGO et CGO. Ces matériaux ont été intégrés comme cathode, anode et électrolyte respectivement dans un dispositif type micro-SOFC fonctionnant vers 400-600°C à partir de H2 comme carburant. L'architecture de la cellule et son procédé de synthèse diffèrent de ceux proposés dans la littérature. En effet, des gradients de porosité et de composition ont été réalisés aux électrodes de manière à limiter les phénomènes de polarisation d'activation et de concentration. De plus, le choix du procédé de synthèse, sol-gel couplé à la méthode de trempage-retrait pour la mise en forme des matériaux, a été guidé par des critères économiques et de facilité de mise en œuvre. Pour la synthèse des films minces denses d'électrolyte (CGO), une autre méthode de synthèse (ALD) a également été utilisée. Dans ce travail, nous avons étudié plus particulièrement les relations qu'il existe entre les propriétés structurale, microstructurale et électrique des films minces poreux d'électrodes, dans les conditions de synthèse et de fonctionnement in fine de la cellule. Sur la base de cette étude, la fabrication et l'évaluation des propriétés électriques de ces micro-SOFC déposées sur un support poreux de Pt/Al2O3 ont été réalisées
7
Salacruch, Céline. "Electrodéposition d'alliages zinc-nickel sur acier et post-traitement anti-corrosion sans chrome." Toulouse 3, 2007. http://thesesups.ups-tlse.fr/159/.
Повний текст джерелаАнотація:
Ces travaux portent sur l'électrodéposition d'alliages zinc-nickel en milieu alcalin sur un substrat en acier en vue d'applications anti-corrosion dans le secteur aéronautique. L'étude des caractéristiques physico-chimiques des dépôts, élaborés à partir d'une formulation standard, montre la nécessité d'ajouter à celle-ci des additifs pour limiter l'évolution morphologique des dépôts en fonction de la densité de courant appliquée. Une étude électrochimique des premiers instants de croissance permet de définir les concentrations en cations métalliques et le mode de préparation optimums de l'électrolyte, permettant de déposer des revêtements épais de teneur en nickel comprise entre 13 et 14%mass, monophasés gamma et de microstructure uniforme sur une plage de densités de courant comprise entre 1 et 10 A. Dm-2. Pour évaluer la fragilisation de l'acier occasionnée par l'hydrogène formé au cours de l'électrodéposition, des tests mécaniques de traction sont effectués. Ils mettent en évidence l'efficacité d'une interface dépôt/substrat riche en nickel contre la diffusion de l'hydrogène dans l'acier. Un post-traitement thermique de déshydrogénation est cependant indispensable pour limiter la fragilisation de l'acier. Pour accroître les propriétés anti-corrosion des dépôts ZnNi, une étude est menée sur l'élaboration par voie sol-gel d'un revêtement de finition sans chrome. Après l'étude de l'influence des paramètres opératoires sur les caractéristiques du film déposé, nous montrons que dans le cas d'un dépôt sur un acier à haute limite élastique, celui-ci confère au revêtement ZnNi une meilleure protection contre la corrosion qu'une couche de conversion à base de chrome hexavalentThis work deals with the electrodeposition of zinc-nickel alloys from alkaline bath on steel substrate for anti-corrosion applications in the aerospace field. The study of the physicochemical characteristics of deposits, produced from a standard formulation, shows the need to add additives in order to limit the morphological evolution of deposits with the applied current density. An electrochemical study just at the beginning of growing shows that it is possible to determine both the optimal concentrations of metallic cations and the elaboration process of the electrolyte allowing to deposit thick coatings with a nickel content in the range of 13 to 14%mass, with single-phased gamma and uniform microstructure for current densities between 1 and 10 A. Dm-2. To evaluate the embrittlement of steel caused by the hydrogen produced during the electrodeposition, mecanical tests are carried out. They underline the benefit of a coating/substrate interface with high nickel content to avoid the diffusion of hydrogen into steel. However, it has been shown that a thermal post-treatment of deshydrogenation is essential to limit the embrittlement of steel. To increase the anti-corrosion properties of zinc-nickel coatings, a study on a finishing deposit without chromium obtained from sol-gel route has been carried out. After studing the influence of experimental parameters on the characteristics of deposited films, we have shown that, for mechanical high-strength steel, sol-gel deposit confers to zinc-nickel coating a better protection against corrosion than a conversion layer containing hexavalent chromium
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Mitronika, Maria. "Dépôt de couches minces de TiO2 – SiO2 par association plasma et sol-gel : impact du procédé de dépôt et de la composition sur les propriétés, application à l'optique intégrée." Thesis, Nantes, 2020. http://www.theses.fr/2020NANT4013.
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Ce travail décrit une approche hybride couplant le procédé de dépôt chimique en phase vapeur assistée par plasma (PECVD) avec l’injection d’une solution colloïdale fabriquée au laboratoire pour la synthèse de films inorganiques nanocomposites (NC) incluant des nanoparticules de TiO2 (NPs) dans une matrice SiO2. Deux études préliminaires ont été réalisées en utilisant les deux méthodes classiques de dépôt : enduction centrifuge et PECVD. La première nous a permis de mieux comprendre les interactions des NPs de TiO2 avec un plasma O2 à basse pression (3m Torr) et la seconde d’élucider la nature de l'interface entre les NPs cristallines et la silice amorphe préparée par PECVD. Pour l'approche hybride en une étape, tout d'abord, l'optimisation de la procédure d'injection des NPs de TiO2 dans un plasma O2 basse pression a été mise en oeuvre. Il a été démontré par calcul et prouvé expérimentalement que les principaux paramètres prolongeant la durée de vie des gouttelettes de solution colloïdale (ce qui peut induire des hétérogénéités du film et une pollution dans le réacteur) sont la volatilité du solvant, la géométrie du système, les espèces de plasma et la température entourant les gouttelettes. Ensuite, les nanocomposites ont été préparés en injectant simultanément des NPs de TiO2 dans le plasma O2- hexaméthyldisiloxane (HMDSO) comme précurseur d'une matrice de silice inorganique. Dans l'ensemble, la structure anatase et la taille des NPs de TiO2 sont conservées dans le film NC. En faisant varier les paramètres d'injection, il a été montré que, dans la matrice SiO2, qui est de bonne qualité optique, la teneur en NPs peut être réglée de 1 à 50% conduisant à des propriétés optiques ajustablesWith the present work we propose a hybrid approach coupling the Plasma Enhanced Chemical Vapor Deposition (PECVD) process with injection of lab-made colloidal solution for the synthesis of inorganic TiO2-SiO2 nanocomposite (NC) films. Two preliminary studies were carried out using the conventional deposition methods: spin coating and PECVD. The first one allowed us to gain insights on the low O2 plasma – NPs interactions and the second one on the nature of the interface between the crystalline NPs and the amorphous PECVD SiO2. For the one-step hybrid approach, first, the optimization of the injection procedure of TiO2 NPs in an O2 lowpressure plasma was implemented. It was shown computationally and proven experimentally that the main parameters prolonging the lifetime of the solution droplets (causing heterogeneities in the film and pollution in the reactor) is the solvent volatility, the system geometry, the plasma species and the temperature surrounding the droplets. Second, the nanocomposites were prepared by simultaneously injecting TiO2 NPs into the O2-hexamethyldisiloxane (HMDSO) plasma leading to a inorganic silica matrix of optical quality. In the overall, both the anatase structure and the 3 nm size of the TiO2 NPs were retained in the NC film. By varying the injection parameters, it was shown that the anatase NP content in the SiO2 matrix can be tuned from 1 to 50% leading to adjustable optical properties
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Gillot, Jessy. "Synthèse et cristallisation de silicates amorphes poreux dans le ternaire MgO-CaO-SiO2 : application à la transition amorphe-cristal des disques d’accrétion." Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10059/document.
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La poussière interstellaire peut être considérée comme le précurseur des minéraux qui ont peuplé les disques protoplanétaires. En effet, les étoiles commencent leur histoire par l’effondrement d’un nuage interstellaire composé de gaz et de silicates amorphes riches en magnésium. Dans les premiers temps de la formation stellaire, celui-ci est réarrangé sous forme d’un disque en orbite autour l’étoile et dans lequel la poussière subit d’intenses transformations. Une conséquence majeure est l’apparition d’une transition amorphe-cristal de la poussière. Le disque est alors caractérisé par une zonation minéralogique constituée par une variation d’abondance de deux phases majeures, la forstérite et l’enstatite. Deux mécanismes peuvent rendre compte de leur formation à partir des silicates amorphes qui alimentent le disque : l’évaporation-condensation et la cristallisation solide-solide. Les présents travaux étudient ce dernier mécanisme comme alternatif au premier pour donner des éléments d’interprétation à la zonation minéralogique observée. Dans un premier temps, une méthode de synthèse sol-gel est mise au point afin de produire des silicates amorphes magnésiens et magnéso-calciques analogues aux silicates interstellaires. Dans un second temps, leur cristallisation est étudiée par diffraction des rayons X et microscopie électronique à transmission. Cette cristallisation se fait de manière séquencée et est marquée par une forte germination, conférant une petite taille de grain aux silicates. Les phases les plus riches en alcalino-terreux se forment les premières. Ce comportement se révèle un mécanisme pertinent pour expliquer la zonation minéralogique des disques et certains minéraux contenus dans les objets tels que les poussières interplanétaires, les comètes et les météoritesIn the framework of mineral evolution, interstellar dust could be claimed as the oldest ancestor of all minerals which spread on Earth and, further, in all comic objects traveling through the solar system, like comets, meteorites and interplanetary dust particles. History of stars begin with the collapse of an interstellar cloud made of gas and dust. Dust is mainly composed of Mg-rich amorphous silicates. In first stages of star formation, the diffuse mixture of gas and dust is dragged out by stellar winds and radiations to form a accretion disk in orbital motion around the new burning body. Then, processing of dust occurs. One consequence is an impressive amorphous-crystal transition known as the ‘crystalline revolution’. A mineral zoning appears along the disk with the formation of two major Mg-rich crystalline silicates, forsterite and enstatite. Two mechanisms can account for the formation of these two phases from the in-falling amorphous dust : evaporation-condensation and solid crystallization. The present work focuses on the solid state crystallization process in order to give support for the interpretation of the mineralogical zoning. First, a sol-gel synthesis is worked out to produce amorphous and porous magnesium and calcium rich silicates as analogs of interstellar dust. Second, their crystallization behavior is studied by x-ray diffraction and by transmission electron microscopy. Main results are an enhanced nucleation and a sequenced crystallization with systematic Mg- or Ca- enriched crystalline phases formed at first. Using a material science frame, the results are discussed in the context of the mineralogical zoning in disks and the occurrence of crystalline silicates in extraterrestrial objects such as interplanetary dust particles, comets and meteorites
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Rodrigues, Leonardo Ribeiro. "Sintese e caracterização de hidroxiapatita e titania nanoestruturadas para a fabricação de compositos." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263083.
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Orientador: Cecilia Amelia de Carvalho ZavagliaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: A hidroxiapatita e a titânia são cerâmicas muito pesquisadas no mundo inteiro, graças às suas excelentes qualidades em diversas áreas, porém neste trabalho o foco foi a sua utilização como biomateriais. Neste trabalho é apresentada a síntese e a caracterização de hidroxiapatita e titânia nanoestruturadas e a fabricação e caracterização de compósitos a partir destes materiais. Os métodos de obtenção de hidroxiapatita foram as rotas sol-gel convencional, sol-gel com sacarose e sol-gel com glicose. Para a síntese da titânia foi utilizado um método desenvolvido no laboratório. Foram utilizados na caracterização da hidroxiapatita: difração de raios X associado com a equação de Scherrer, fluorescência de raios X, microscopia eletrônica de varredura e ensaio mecânico de compressão. Para a titânia foram utilizados os mesmos tipos de caracterização, porém com a adição da espectroscopia Raman. Os resultados foram excelentes podendo ser destacados: baixo custo dos reagentes, facilidade de realização dos processos de síntese, pequenos nanocristalitos com 52 a 100nm para hidroxiapatita e 27 a 62nm para a titânia. O compósito apresentou boa distribuição entre as partículas de hidroxiapatita e titânia e uma evidente melhora na resistência à compressão quando comparado com o pó compactado de hidroxiapatita sem reforço
Abstract: Hydroxyapatite and titania are ceramics which have been given a lot of attention around world because of their outstanding properties in multiple fields such as the one of biomaterials which is the aim of this work. The synthesis and caracterization of nanostructured hydroxyapatite and titania, for composites fabrication is presented in this work. The synthetic routes employed for the hydroxyapatite synthesis were the conventional sol-gel process, the sol-gel process with sucrose, and sol-gel process with glucose. The synthesis of titania was performed by a method developed in the laboratory. Hydroxyapatite characterization was made by: X-ray diffraction associate with the Scherrer equation, X-ray fluorescence, scanning electron microscopy and compression mechanical test. For titania it was used the same characterization procedures, however, they were complemented with Raman spectroscopy. From the results it could be concluded that the synthesis methods employed were efficient in obtaining nanocrystallites sized from 52 to 100nm and from 27 at 62nm for hydroxyapatite and titania, respectively. On the composite formulation hydroxyapatite and titania particles were well distributed and its mechanical resistance were higher than the one obtained by the hydroxyapatite without the titania reinforcement
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
Книги з теми "Sol-gel composition"
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Bansal, Narottam P. Sol-gel synthesis of MgO-SiO glass compositions having stable liquid-liquid immiscibility. [Washington, DC]: National Aeronautics and Space Administration, 1987.
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Bansal, Narottam P. Sol-gel synthesis of MgO-SiO glass compositions having stable liquid-liquid immiscibility. [Washington, DC]: National Aeronautics and Space Administration, 1987.
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United States. National Aeronautics and Space Administration., ed. Sol-gel synthesis of MgO-SiO □glass compositions having stable liquid-liquid immiscibility. [Washington, DC]: National Aeronautics and Space Administration, 1987.
Знайти повний текст джерелаЧастини книг з теми "Sol-gel composition"
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Quintero, L. A., and D. M. Escobar. "Chemical Composition Effect of Sol-Gel Derived Bioactive Glass Over Bioactivity Behavior." In Proceedings of the 3rd Pan American Materials Congress, 11–19. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-52132-9_2.
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Predoana, Luminita, Dániel Attila Karajz, Vincent Otieno Odhiambo, Irina Stanciu, Imre M. Szilágyi, György Pokol, and Maria Zaharescu. "Influence of the Microwaves on the Sol-Gel Syntheses and on the Properties of the Resulting Oxide Nanostructures." In Microwave Heating [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94931.
Повний текст джерелаАнотація:
Among the chemical methods in the liquid phase, the sol–gel technique is a versatile and efficient method for pure or doped metal oxide films or powders preparation, showing some advantages over other preparation techniques (high homogeneity, the possibility to introducing dopants in large amount, low processing temperature and control over the stoichiometry). Combining the sol–gel (SG)method with the effect of ultrasounds(US) or microwaves (MW) leads to improving the sol–gel procedure. The microwave-assisted sol–gel method is most frequently used for obtaining nanocrystalline, monodispersed oxide nanoparticles, or to transform amorphous gels into well-crystallized nanopowders. Less studied is the influence of the microwaves on the sol–gel reactions in solutions. The benefit of using microwave-assisted sol–gel preparation highly depends on the reagents used and on the composition of the studied systems. In the present chapter, results on the influence of the microwaves on the chemical reactions that take place during the sol–gel synthesis and on the properties of the resulted samples are discussed.
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Predoanǎ, Luminita, Dániel Attila Karajz, Vincent Otieno Odhiambo, Irina Stanciu, Imre M. Szilágyi, György Pokol, and Maria Zaharescu. "Influence of the Microwaves on the Sol-Gel Syntheses and on the Properties of the Resulting Oxide Nanostructures." In Microwave Heating - Electromagnetic Fields Causing Thermal and Non-Thermal Effects. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94931.
Повний текст джерелаАнотація:
Among the chemical methods in the liquid phase, the sol–gel technique is a versatile and efficient method for pure or doped metal oxide films or powders preparation, showing some advantages over other preparation techniques (high homogeneity, the possibility to introducing dopants in large amount, low processing temperature and control over the stoichiometry). Combining the sol–gel (SG)method with the effect of ultrasounds(US) or microwaves (MW) leads to improving the sol–gel procedure. The microwave-assisted sol–gel method is most frequently used for obtaining nanocrystalline, monodispersed oxide nanoparticles, or to transform amorphous gels into well-crystallized nanopowders. Less studied is the influence of the microwaves on the sol–gel reactions in solutions. The benefit of using microwave-assisted sol–gel preparation highly depends on the reagents used and on the composition of the studied systems. In the present chapter, results on the influence of the microwaves on the chemical reactions that take place during the sol–gel synthesis and on the properties of the resulted samples are discussed.
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"Structure and Properties of Composite Adsorbents Salt Inside Porous Matrix." In Technology Development for Adsorptive Heat Energy Converters, 43–87. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4432-7.ch003.
Повний текст джерелаАнотація:
The chapter is devoted to structure and properties of composite adsorbents ‘salt inside porous matrix'. Characteristics of adsorbents ‘salt inside porous matrix', such as ‘zeolite – crystalline hydrate', ‘vermiculite – crystalline hydrate', ‘silica gel – crystalline hydrate' were analysed. Main advantages of composite adsorbents are shown to be higher adsorptive capacity and lower regeneration temperature as compared with host matrix. Adsorptive capacities of composite materials are shown to be significantly enhanced by introduction of salts in host matrix such as zeolite, vermiculite, or silica gel. Water uptake by composite adsorbent is shown to be increased by rising the salt content in it. The drawback of most of existing impregnation technologies is shown to be impossibility of obtaining composite with salt content more than 40 – 60% along with complexity. Sol gel method is shown to be an alternative for conventional impregnation methods. Properties of adsorbents ‘silica gel – sodium sulphate' synthesized according to sol gel method developed by authors were considered. The composite ‘silica gel – sodium sulphate' composition and structure were studied by IR-spectroscopy and wide-angle x-ray scattering. Adsorptive properties of crystalline Na2SO4 when allocated in silicon oxygen matrix are shown to result from dispersion up to nanoscale. Adsorptive capacities and heat of adsorption of composites ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' surpass almost by 30% the value calculated from the linear superposition of the sorption capacities of the sorbent and massive salt. Their adsorption properties are shown to be not a linear combination of properties of silica gel and salt. The formation of a unique structure promoting an increase in the rate of reaction between crystalline hydrates and water vapor in the developed pores of the silicon-oxygen matrix is confirmed. It leads to increasing the heat of adsorption and the heat energy storage density. Strong difference of water sorption kinetic curves of composite ‘silica gel – sodium sulphate' and massive sodium sulphate is revealed. The correlation of their composition, structure, water adsorption kinetic, and operating characteristic as heat storage material is stated.
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"Design of Adsorptive Heat Storage Devices." In Technology Development for Adsorptive Heat Energy Converters, 89–123. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4432-7.ch004.
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The chapter is devoted to prospects of application of adsorptive heat storage devices, principles of operating the adsorptive heat storage systems, design of adsorptive storage devices and main factors determining the design of adsorptive heat storage unit. Perspectives of application of adsorptive heat storage devices in heat supply systems were analyzed. Basic principles of operating of heat storage devices were considered. Adsorptive heat storage units operating in close and open modes were compared. Constructions of adsorptive heat storage units operating in open and close mode were described. An efficient algorithm for calculating the volume of the adsorptive thermal energy storage device for a decentralised heat supply system of a private house is suggested by authors. The following procedure of computation is proposed to involve: calculation of thermal load for heating including the determination of thermal losses through external fences, thermal losses due to infiltration and internal heat dissipation, the evaluation of maximal adsorption, adsorption heat, and determination of adsorbent mass and adsorbent volume. The maximal adsorption value is suggested to be calculated by the characteristics of the adsorbent, that is, its maximal adsorption or in the absence of data for a composite adsorbent, as a linear superposition for a mechanical mixture. The adsorbent mass is suggested to calculate as a ratio of a thermal load for heating and heat of adsorption. The adsorbent volume is calculated as ratio of mass and density of adsorbent. An evaluative calculation of the heat load for a private house was carried out with the proposed algorithm. Mass and volumes of conventional silica gels were compared with composite adsorbents ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' obtained by sol gel method developed by authors. Mass and volume of silica gels occur to surpass the suggested composite at least by 1.5 – 5 times. This is shown to result from higher maximal adsorption and heat of adsorption of suggested composite adsorbents. The optimal composition of the composite adsorbents ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' was determined according to the minimal volume of the layer of heat storage material. Both the lowest volume values and the highest efficiency of a composite adsorbents with a mass ratio of silica gel and Na2SO4 or CH3COONa 20: 80 are explained by the maximum value of adsorption heat. Suggested composite adsorbent ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' are shown to be promising for heat supply systems.
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Trigos, José Bruno Rojas, Yolanda Jiménez-Flores, Víctor Suárez, Moseratt Suárez-Quezada, and Uriel Nogal. "Sol-Gel Synthesis of Calcium-Deficient Hydroxyapatite: Influence of the pH Behavior during Synthesis on the Structural, Chemical Composition and Physical Properties." In Powder Technology. InTech, 2018. http://dx.doi.org/10.5772/intechopen.76531.
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Mahadik, Satish A., F. Pedraza, and Sarika S. Mahadik. "Sol-Gel-Based Multifunctional Superhydrophobic Coatings and Its Tribological Properties." In Handbook of Research on Tribology in Coatings and Surface Treatment, 270–300. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-7998-9683-8.ch012.
Повний текст джерелаАнотація:
This chapter summarizes key issues in the fields of multifunctional superhydrophobic coatings with an analysis of their tribological properties. In this respect, the authors explore a simple sol-gel process strategy and tribological properties controlled through a reaction of ORMOSIL-based polymers that generate multifunctional minimum free energy structures of micro- to nano-scale siloxane chains. Different compositions and dimensions of solid materials (contact angle = 150° and sliding angle = 10°) can be superhydrophobic fabricated through various deposition methods. The complete waterproof layering has been demonstrated to have excellent cost, scalability, and especially the ability to encapsulate other functional groups. The perspectives have established many significant functionalities with better tribological properties for the next generation of smart multifunctional superhydrophobic coatings.
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Wani, Irshad A. "Nanomaterials, Novel Preparation Routes, and Characterizations." In Advances in Environmental Engineering and Green Technologies, 1–40. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-6304-6.ch001.
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The important aspect of nanotechnology is the remarkable size dependant physico-chemical properties of nanomaterials that have led to the development of synthesis protocols for synthesizing nanomaterials over a range of sizes, shapes, and chemical compositions. This chapter describes the various aspects of nanotechnology: its dimensions and manipulation of matter with primary focus on inorganic materials. Detailed accounts of various methods lying within top-down and bottom-up synthesis approaches are discussed, like Chemical Vapour Condensation (CVC), arc discharge, hydrogen plasma-metal reaction, and laser pyrolysis in the vapour phase, microemulsion, hydrothermal, sol-gel, sonochemical taking place in the liquid phase, and ball milling carried out in the solid phase. The chapter also presents a brief account of the various characterization techniques used for the identification of the nanomaterials: X-ray diffraction, UV-visible spectroscopy, and electron microscopy (e.g. Transmission Electron Microscopy [TEM], Scanning Electron Microscopy [SEM], Atomic Force Microscopy [AFM]).
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Mahmood, Wan Ahmad Kamil, and Mohammad Hossein Azarian. "Inorganic-Organic Composite Materials from Liquid Natural Rubber and Epoxidised Natural Rubber Derivatives." In Applied Environmental Materials Science for Sustainability, 128–40. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1971-3.ch006.
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Organic-Inorganic composite materials (OICs) are used to describe the group of materials synthesized from polymers and inorganic metal alkkoxides. The interests in these materials arised from the need to ‘combine' the physical properties of inorganic glass materials and polymers such that the resultant OICs have the strength of the inorganic glass and flexibiliy of polymeric materials. Sol-gel technique have been the technique of choice due to much of its advantages, in particular the low temperature reaction. This is very important when natural rubber and its derivatives are used as the polymer component of the OICs. Work in our laboratory has demonstrated that OICs form liquid natural rubber (LNR) and 50% epoxidised natural rubber (ENR-50) can be prepared from various metal alkoxides, such silicon, zirconium and titanium. The OICs can be prepared as flexible transparent films, nanofibers and nanobeads. This Chapter will describe the preparation techniques and the properties of these OICs from various compositions of one and more metal alkoxides in both LNR and ENR-50. The applications of these materials in PANI will be briefly described.
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Wang, X. Z., W. H. Li, T. Dou, and B. Zhong. "Compositional effects of bimodal mesopore silica synthesized by a base- catalyzed ambient pressure sol-gel processing." In Nanotechnology in Mesostructured Materials, Proceedings of the 3rd International Materials Symposium, 255–58. Elsevier, 2003. http://dx.doi.org/10.1016/s0167-2991(03)80375-0.
Повний текст джерелаТези доповідей конференцій з теми "Sol-gel composition"
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Jones, Steven M. "Gradient composition sol-gel materials." In Symposium on Integrated Optoelectronics, edited by Bruce S. Dunn, Edward J. A. Pope, Helmut K. Schmidt, and Masayuki Yamane. SPIE, 2000. http://dx.doi.org/10.1117/12.384345.
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Hough, David, and Michael DeAngelis. "SOL-GEL SYNTHESIS OF TARGETED COMPOSITION NANOSCALE OLIVINE." In GSA Connects 2021 in Portland, Oregon. Geological Society of America, 2021. http://dx.doi.org/10.1130/abs/2021am-369246.
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Lu, ZhiGuo, Yinsui Zhou, Aihua Gao, Xiaoyun Hu, and Xiaowei Lu. "Appearance and composition of sol-gel-derived TiO2/SiO2 interference coatings." In Symposium on Integrated Optoelectronics, edited by Bruce S. Dunn, Edward J. A. Pope, Helmut K. Schmidt, and Masayuki Yamane. SPIE, 2000. http://dx.doi.org/10.1117/12.384350.
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Bingrong Yuan, Shengwen Yu, Wufeng Yang, Xiaowen Zhou, and Jinrong Cheng. "Composition dependence of xBiFeO3-(1-x)PbTiO3 films prepared by sol-gel technique." In 2009 18th IEEE International Symposium on the Applications of Ferroelectrics (ISAF). IEEE, 2009. http://dx.doi.org/10.1109/isaf.2009.5307556.
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Lin, S. L., H. Y. Wang, C. K. Chung, and S. F. Chuang. "The effect of sol-gel composition ratio on phase transformation of titanium dioxide under CO2 laser annealing." In 2011 IEEE International Conference on Nano/Micro Engineered and Molecular Systems (NEMS). IEEE, 2011. http://dx.doi.org/10.1109/nems.2011.6017548.
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Pillonnet, Anne, Roger Brenier, Claudine Garapon, and Jacques Mugnier. "Influence of annealing temperature on composition and stresses of alumina thin films elaborated by the sol-gel method." In Optical Systems Design, edited by Laurent Mazuray, Philip J. Rogers, and Rolf Wartmann. SPIE, 2004. http://dx.doi.org/10.1117/12.513412.
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Jing, Yang, Jianbin Luo, and Tianmin Shao. "Thickness and Processing Effects on the Composition and Actuating Force of Pb(Zr,Ti)O3 Thin-Film Micro-Actuator for Hard Disk Drives." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63316.
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Sol-gel process associated with integrated circuit (IC) technique was used to fabricate Lead-zirconate-titanate (PZT) films with different thickness and process parameter on Pt/Ti/SiO2/Si substrates. Meanwhile, a new dual-stage actuator system including a piezoelectric micro-actuator and a voice coil motor for positioning a magnetic head for high-density hard disc devices (HDDs) have been designed, fabricated. Fig. 1 shows the structure illustration of the micro-actuator that consists of slider, “U”-type substrate and piezoelectric multilayer elements. The crystalline structure and growth behavior of the films with different thickness have been studied by X-ray diffraction, scanning electron microscopy, and Auger electron spectroscopy. The structure of piezoelectric element is as Pt/Ti/PZT/Pt/Ti multi-layer film.
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Jung, Hye-Mi, Jung-Hun Noh, and Sukkee Um. "Experimental Study of Electrical Switching Characteristics of Vanadium Oxide Thin Films on Bipolar Plates for Improving Thaw-at-Start." In ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology collocated with ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/fuelcell2011-54561.
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The ultimate goal of cold start of hydrogen-powered polymer electrolyte fuel cell vehicles is to minimize the significant system thaw energy requirement and to achieve the short time period desired for freeze start (e.g. less than 30 seconds) in a subfreezing environment. As part of an effort to improve cold start capability for fuel cell vehicles, this work presents a new thaw-at-start strategy using electrical characteristics of vanadium oxide thin films as self-heating source at sub-zero temperature. Vanadium-based thin film coated on the surface of flat bipolar plates (e.g. carbon-based graphite and metallic bipolar plates) have been synthesized by a dip-coating method via aqueous sol-gel chemistry. Subsequently, the detailed in-/ex-situ analyses of the thin films have been carried out using diverse diagnostic techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) to investigate the chemical composition, crystallinity, and microstructure. In addition, electrical switching characteristics of the thin films on bipolar plates was cautiously observed over a temperature range from −20°C to 80°C by means of 4-point probes installed in a thermo -hygrostat. By doing so, it has been possible to correctly infer the relationship between a tendency of the thermally-induced electrical switching hysteresis and bipolar plate materials. Also, comprehensive theoretical study on the basis of the experimental results have been performed to estimate the heat dissipation rate by Joule heating from the solid thin films on bipolar plates for the rapid cold-start operation of fuel cell vehicles.
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Jena, Hrudananda, and B. Rambabu. "Effect of Sonochemical, Regenerative Sol Gel and Microwave Assisted Synthesis Techniques on the Formation of Dense Electrolytes and Porus Electrodes for All Perovskite IT-SOFCs." In ASME 2006 4th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2006. http://dx.doi.org/10.1115/fuelcell2006-97262.
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The influence of preparation techniques on the microstructure, grain-size and consequently on the electrical transport properties of the ABO3 structured materials used as electrode and electrolytes in all perovskite IT-SOFC were investigated. Nano-crystalline powders of La1-xMxGa1-yNyO3±δ (M = Sr,; x = −0.10 to 0.15; N = Mg; y = −0.10 to 0.15) (LSGM) as electrolyte, porous La0.8Sr0.2Co0.8Fe0.2O3±δ (LSCF) or LaNi1-xFexO3±δ (x = 0–0.5) (LNF) as cathode, La0.8Sr0.2Cr0.7Mn0.3O3±δ (LSCM) as anode and LaCrO3 or substituted LaCrO 3 as interconnect were synthesized by various wet chemical methods. The wet chemical methods like metal-carboxylate gel decomposition, hydroxide co-precipitation, sonochemical and regenerative sol-gel process followed by microwave sintering of the powders have been used. Microwave sintering parameters were optimized by varying sintering time, and temperature to achieve higher density of LSGM pellets. The phase pure systems were obtained at sintering duration of 30 min at 1200 °C. The XRD, HR-TEM, and SEM measurements revealed the average grain size of these perovskites was ∼ 22 nm range. The electrical conductivities of the compositions were measured by ac (5Hz–13MHz) and dc techniques. The conductivity of the sintered pellets was found to be ∼0.01–0.21 S/cm at 550–1000°C range for electrolyte and 1.5–100 S/cm at 25–1000°C for electrodes respectively. The effect of sonochemical, and regenerative sol-gel methods in processing large quantities of nano-crystalline perovskites with multi-element substitutions at A- and B-sites to achieve physico-chemical compatibility for fabricating zero emission all perovskite IT-SOFCs are reported in this paper.
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Neminushchaya, S., E. Tomina, and A. Dmitrenkov. "THE USE OF NANOSCALE ZINC OXIDE IN WOOD-BASED COMPOSITIONS." In Modern machines, equipment and IT solutions for industrial complex: theory and practice. FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov, 2021. http://dx.doi.org/10.34220/mmeitsic2021_256-260.
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The aim of this work was to study compositions based on vegetable oil waste and nanoscale zinc oxide particles for processing natural wood. The sol-gel method was used for the synthesis of zinc oxide nanoparticles. The synthesized zinc oxide nanoparticles did not contain impurities and had a shape close to spherical, and their size did not exceed 20 nm. We used freshly prepared suspensions of zinc oxide nanoparticles in used vegetable oil with their content in the amount of 0.1, 0.5 and 1.0 wt. parts per 100 parts of oil. The wood was treated by hot-cold impregnation. The tests were carried out on samples of birch and pine wood of standard sizes. In the modified samples, the wetting angle, moisture and water absorption, as well as their swelling were determined. It is shown that the use of zinc oxide nanoparticles in compositions based on vegetable oil waste can significantly reduce the moisture and water resistance of wood and reduce its swelling. The optimal dosages of the nanopowder introduced into the used vegetable oil and the conditions of impregnation were selected. The compositions used on the basis of vegetable oil waste are characterized by environmental safety, and the resulting wood samples had an improved appearance.
Звіти організацій з теми "Sol-gel composition"
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Yordanov, Stancho I., Irina D. Stambolova, Luben I. Lakov, Sasho V. Vassilev, and Bojidar T. Jivov. Sol-gel CeO2 and ZrO2 Coatings on CeO2: Study of the Phase Composition, Morphology and Corrosion Resistance. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, February 2019. http://dx.doi.org/10.7546/crabs.2019.01.07.
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