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Electrophoretic deposition of Ba0.77Ca0.23TiO3 nanopowders

ANTONELLI, Eduardo; SILVA, Ronaldo Santos; VICENTE, Fabio Simoes de; ZANATTA, Antônio Ricardo; HERNANDES, Antônio Carlos
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
67.89708%
Ba0.77Ca0.23TiO3 (BCT23) nanometric powders, synthesized by the modified Pechini method, were used as precursor to produce thick films (50-130 mu m) employing the electrophoretic deposition (EPD) technique. The BCT23 powder presented a single crystalline phase with an average particle size and a crystallite size of similar to 60 nm and similar to 20 nm, respectively, when calcined at 800 degrees C/2h. BCT23 thick films were deposited on platinum substrates starting from different suspensions prepared by dispersion of the powder into: isopropyl alcohol (IPA) or a mixture of acetylacetone (Acac) and ethanol (EtOH) (1:1, volumetric ratio). A milling process was used to deagglomerate the powders in order to increase the suspension stability and improving the deposition. Dense and crack free thick films with uniform microstructure were obtained after sintering at 1300 degrees C/2 h from Acac+EtOH solution. (C) 2007 Elsevier B.V. All rights reserved.

Platinum nanoparticle-modified electrodes, morphologic, and electrochemical studies concerning electroactive materials deposition

VIDOTTI, Marcio; GONCALES, Vinicius R.; QUARTERO, Vinicius S.; DANC, Barbara; TORRESI, Susana I. Cordoba de
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
57.96428%
The present work describes the synthesis of platinum nanoparticles followed by their electrophoretic deposition onto transparent fluorine-doped tin oxide electrodes. The nano-Pt-modified electrodes were characterized by voltammetric studies in acidic solutions showing a great electrocatalytic behavior towards H(+) reduction being very interesting for fuel cell applications. Morphological characterization was performed by atomic force microscopy on different modified electrodes showing a very rough surface which can be tuned by means of time of deposition. Also, nickel hydroxide thin films were galvanostatically grown onto these electrodes showing an interesting electrochemical behavior as sharper peaks, indicating a faster ionic exchange from the electrolyte to the film.; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); CNPq[200261/2008-8]; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Fapesp[05/59560-9]

Electrostatic layer-by-layer and electrophoretic depositions as methods for electrochromic nanoparticle immobilization

VIDOTTI, Marcio; TORRESI, Susana I. Cordoba de
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
57.636675%
The present paper describes the immobilization of nanoparticles onto conducting substrates by using both electrostatic layer-by-layer and electrophoretic deposition (EPD) methods. These two techniques were compared in high-performance electrochromic electrodes based on mixed nickel hydroxide nanoparticles. In addition to easy handling, EPD seems to be the most suitable method for the immobilization of nanoparticles, leading to higher electrochromic efficiencies, lower response times and higher stability upon coloration and bleaching cycling. (C) 2008 Elsevier Ltd. All rights reserved.; FAPESP[03/10015-3]; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); FAPESP[03/00629-4]; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); CNPq[152312/2007-2]

Electrophoretic deposition of BaTi0.85Zr0.15O3 nanopowders

Antonelli, Eduardo; Silva, Ronaldo Santos da; Bernardi, Maria Inês Basso; Hernandes, Antônio Carlos
Fonte: Universidade Federal de São Carlos - Departamento de Engenharia de Materiais; São Carlos Publicador: Universidade Federal de São Carlos - Departamento de Engenharia de Materiais; São Carlos
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
68.012817%
The present study reports the results of thick films (20-130 μm) produced through electrophoretic deposition of BaTi0.85Zr0.15O3 (BTZ) nanometric powders synthesized by the Pechini’s method. The BTZ powderscalcined at 600°C/2h presented a single crystalline phase with an average particle size of ~20nm. To thick films deposition, a stable suspension of acetylacetone (Acac) and ethanol (EtOH)was prepared and the powder was deposited on platinum substrates. The viscosity of BTZ powders suspensions as a function of operational pH (OpH)was measured and the reactions between nanoparticles and the media were discussed. A milling process was used to deagglomerate the powders and it had a great influence in the suspension stability and deposition of thick films. Dense and crack-free thick films were obtained after sintering at 1220 °C/1h. The dielectric properties results, comparable with those of bulk BTZ ceramics, suggested potential applications of the EPD process for the deposition of ferroelectric/piezoelectric thick films.; FAPESP; FAPITEC/SE; CNPq; CAPES

High-voltage electrophoretic deposition of preferentially oriented films from multiferroic YMn2O5 nanopowders

Brankovic, G.; Brankovic, Z.; Sequinel, T.; Zunic, M.; Vukovic, M.; Tasic, N.; Marinkovic, B. A.; Cilence, M.; Varela, José Arana; Longo, Elson
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 2065-2068
ENG
Relevância na Pesquisa
68.16553%
Processing of the YMn2O5 powder is very challenging, since it decomposes to YMnO3 and Mn3O4 at temperatures close to 1180 °C, while samples consolidation commonly demands high temperatures. The main goal of this work is to investigate a possibility to prepare thick films of YMn2O5, since their deposition generally requires significantly lower temperatures. Multiferroic YMn 2O5 was synthesized by the hydrothermal method from Y(CH3COO)3·xH2O, Mn(CH 3COO)2·4H2O and KMnO4 precursors. XRD, FE-SEM and TEM analysis showed that the obtained powder was monophasic, with orthorhombic crystal structure and columnar particle shape with mean diameter and length of around 20 and 50 nm, respectively. The obtained powder was suspended in isopropyl alcohol with addition of appropriate binder and deflocculant. This suspension was used for electrophoretic deposition of YMn2O5 thick films under the high-voltage conditions and electric fields ranging from 250 to 2125 V/cm. The films obtained at 1000 V/cm and higher electric fields showed good adhesion, particle packing, homogeneity and very low porosity. It was shown that the deposition in extremely high electric fields (KC=2125 V/cm) can influence the crystal orientation of the films, resulting in formation of preferentially oriented films. © 2012 Elsevier Ltd and Techna Group S.r.l.

Fabrication of composite thick films of BaLa4Ti4O15 and Ba4Nd9.33Ti18O54 by electrophoretic deposition

Mahajan, Amit
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
48.080303%
As comunicações sem fios experimentaram um crescimento excepcional nas últimas décadas e que se prevê que continue nos próximos anos (Capítulo 1, Referêcia 3) Com este crescimento há uma procura crescente de dispositivos de menores dimensões e mais versáteis, do que os actualmente existentes, que permitam maiores níveis de integração, possibilidade de operação a altas frequências e produção a custos reduzidos. Actualmente existe também a necessidade de desenvolver materiais com permitividade dieléctrica relativa (εr) entre 40 - 80, baixas perdas dieléctricas e coeficiente de temperatura da frequência de ressonância (tf) próximo de zero. Actividades de investigação e desenvolvimento para explorar a utilização de tecnologias de fabrico de filmes finos e espessos para substituir os materiais cerâmicos em uso corrente, estão actualmente em curso. Neste contexto, foi explorada no presente trabalho a fabricação de filmes espessos por deposição electroforética (EPD) do composto BaLa4Ti4O15 (BLT), cuja selecção se relaciona com as óptimas propriedades que apresenta para aplicação às frequências das microondas. Foi igualmente tentada a preparação de filmes espessos compósitos de BaLa4Ti4O15 (BLT) - Ba4Nd9.33Ti18O54 (BNT) para preenchimento do intervalo existente em termos de materiais com permitividades dieléctricas 40-80. A escolha da deposição electroforética de entre os vários processos de fabricação de filmes espessos prende-se com as características únicas desta técnica...

BaNd2Ti5O14 thick films for microelectronics fabricated by electrophoretic deposition

Zhi Fu
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
48.136143%
Nos dias que correm os engenheiros de circuítos na área da microelectrónica são confrontados com a necessidade de desenhar circuítos que permitam um maior transporte de informação numa menor largura de banda, que consumam menos energia e ao mesmo tempo com a necessidade de criar produtos de dimensões menores e mais flexíveis, com maiores níveis de integração, operação a frequências mais elevadas e a custos mais reduzidos. Neste contexto, a substituição de componentes dieléctricos cerâmicos na forma de monolitos, que são parte integrante de determinados dispositivos microelectrónicos que operam a frequências elevadas (filtros e antennas, por exemplo), por dieléctricos processados na forma de filmes espessos está sob consideração. Com esta aproximação espera-se, por um lado conseguir uma redução do tamanho do dispositivo e dos custos associados à sua produção e por outro lado, e de particular relevância, explorar as oportunidades criadas pela possibilidade de processar filmes conformes com substratos de diferentes formas e de natureza metálica. Novas estruturas e concepções para dispositivos que operam a frequências elevadas deverão ser criadas. Ao mesmo tempo, crê-se contribuir para o desenvolvimento de processos de fabrico de produção em massa de filmes de materiais dieléctricos com desempenho reproductível e a baixos custos. As técnicas de preparação de filmes finos incluem a fabricação por cinta (“tape casting”)...

Formation of TiO2 photoanodes by simultaneous electrophoretic deposition of anatase and rutile particles for photoassisted electrolytic copper ions removal

Peralta-Ruiz,Yeimmy Y.; Lizcano-Beltrán,Erika M.; Laverde,D.; Acevedo-Peña,Próspero; Córdoba,Elcy M.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
Relevância na Pesquisa
58.080303%
The influence of Anatasa/Rutile ratio on TiO2 films, grown by electrophoretic deposition was studied in the photoassisted electrolytic copper ions removal from cyanide solutions. The proper dispersant dosage allowing the simultaneous electrophoretic deposition of Anatase and Rutile was chosen based on electrokinetic measurements; evidenced by the XRD spectra of the formed films. The evaluation of films photoassisted electrolytic copper ion removal showeds that it is possible to enhance the activity of Anatase films by adding some Rutile exploiting the synergetic interaction between these two materials, achieve by its proper deposition.

Electrophoretic fabrication of ZnO/ZnO-CuO composite for ammonia gas sensing

Corpuz,Ryan Dula; Albia,Jason Rayala
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2014 EN
Relevância na Pesquisa
57.89708%
Nanostructured deposits of ammonia (NH3) sensitive ZnO and ZnO-CuO composites were fabricated on a graphite electrode via electrophoretic deposition (EPD). Deposition was done by holding the applied voltage and deposition time constant at room temperature. Testing of sensing properties of the deposits was conducted using Wheatstone bridge circuit. SEM micrographs show a more open structure and more exposed surface area of the pure ZnO deposit compared to the ZnO-CuO deposit. The average particle size deposited at 500V for ZnO and ZnO-CuO were 241nm and 260nm respectively; whereas at 750V the average particle size is 195nm and 276nm, respectively. Deposits with greater surface area, smaller particle sizes and thicker deposits exhibit high gas sensitivity. On the other hand, addition of CuO resulted to a more compact and dense surface structure and decreased gas sensitivity. Thus, particle size and the surface structure of the deposits dictate the sensitivity of the material.

A resistivity model for electrophoretic deposition

Ferrari, Begoña; Moreno, Rodrigo; Cuesta, José A.
Fonte: Trans Tech Publications Publicador: Trans Tech Publications
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em /07/2006 ENG
Relevância na Pesquisa
48.012817%
Electrophoretic deposition (EPD) is a powerful method for obtaining particulate layers in a broad range of thicknesses if an adequate control of the growing kinetics is reached. Existing models of EPD kinetics consider that the growth of the deposit increases linearly with deposition time and deviations are due to a reduction of powder concentration and/or a decrease of electric field when EPD is performed at constant voltage conditions. Experimental observations show that long time tests lead to a S-shaped growing kinetics. This work presents a resistivity model that predicts a S-shape variation of mass per unit area with deposition time, with a first step in which the deposition rate increases, as a consequence of resistivity changes, followed by a decreasing slope associated to the lose of powder concentration. Currently available EPD models, such as the Hamaker and Sarkar & Nicholson models are particular cases of the generalized resistivity model proposed in this work.; This work has been supported by CICYT, Spain (MAT2003-0836). Dr. Ferrari acknowledges CSIC and the European Social Foundation for the concession of a grant.; 6 pages, 2 figures.-- Issue title: "Electrophoretic Deposition: Fundamentals and Applications II".

Electrophoretic deposition of (Zn, Nb)SnO2-films varistor superficially modified with Cr3+

Mascarenhas Morandi Lustosa, Glauco Meireles; Campos da Costa, Joao Paulo de; Perazolli, Leinig Antonio; Stojanovic, Biljana D.; Zaghete, Maria Aparecida
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 2083-2089
ENG
Relevância na Pesquisa
67.797876%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 2013/07296-2; Recently, there has been an important rise in the research and development aimed to improve the properties of SnO2-based varistors. Meanwhile, due to fact that ZnO-based varistors possess better electrical properties compared to SnO2-based varistors, it is shown that it is needful to add additives to improve their properties. In our study, the SnO2-powder was prepared by the chemical route (Pechini method) with addition of ZnO (1 mol%) and Nb2O5 (0.05 mol%). Films were obtained by the electrophoretic deposition of SnO2-based powder, following by microwave oven sintering. Cr3+ was deposited by EPD on the films surface and thermal treatment was carried out in a microwave oven. After electrical characterization the films showed nonlinear coefficient over 10, breakdown voltage around 60 V, low leakage current (approximate to 10(-6) A) and resistance over 200 kg cm. This indicates the efficiency of the used techniques to prepare varistor films with improved electrical properties after Cr3+ diffusion. (C) 2015 Elsevier Ltd. All rights reserved.

Electrophoretic deposition of poly(3-decylthiophene) onto gold-mounted cadmium selenide nanorods

Garate, José-Antonio; English, Niall J.; Singh, Ajay; Ryan, Kevin M.; Mooney, Damien A; MacElroy, J.M.D.
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: info:eu-repo/semantics/article; all_ul_research; ul_published_reviewed
ENG
Relevância na Pesquisa
67.89708%
peer-reviewed; Molecular mechanisms of electrophoretic deposition (EPD) of P3DT poly(3-decylthiophene) molecules onto vertically aligned cadmium selenide arrays have been studied using large-scale, nonequilibrium molecular dynamics (MD), in the absence and presence of static external electric fields. The field application and larger polymer charges accelerated EPD. Placement of multiple polymers at the same lateral displacement from the surface reduced average deposition times due to ‘crowding’, giving monolayer coverage. These findings were used to develop and validate Brownian dynamics simulations of multi-layer polymer EPD in scaled-up systems with larger inter-rod spacings, presenting a generalised picture in qualitative agreement with random sequential adsorption.

Development of High Capacitance Films for Electrical Energy Storage Using Electrophoretic Deposition of BaTiO3 on Ultrasonically Etched Ni

Harari, Berkan
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
68.07823%
High capacitance devices were developed using rapid electrophoretic deposition (EPD) of barium titanate (BaTiO3) on ultrasonically etched nickel (Ni) substrates. The microstructural and electrical properties of films with varying thicknesses, sintering temperatures and substrate etching times were investigated to study their effect on the capacitance. Although increasing the capacitance was the primary goal, decreasing manufacturing costs and reducing environmental impact was also considered. After confirming the tetragonality and particle size of a 0.2 µm hydrothermal powder, it was dispersed in an aqueous-organic mixture of ethanol, acetone and water. A zeta potential of 50 mV was observed at the EPD pH level (6.8). Flocculation or coagulation was not likely in this situation. Therefore, mixing water with an organic solution was an effective method for reducing environmental impact while maintaining deposition quality. The presence of BaCO3 in the films was proven using X-ray diffraction. Other impurities such as TiO2 and NiO were not detected. A significant variation in the average grain size was not observed for films with different thicknesses whereas films sintered at different temperatures displayed greater variation. A bimodal pore size distribution in the samples suggested that the powder was agglomerated after deposition due to a high deposition voltage (20 V). Rapid deposition times of 2 to 8 seconds offered a potential for cost reduction compared to longer deposition times implemented in industry. Therefore the increased porosity was accepted. The dielectric constant of the films increased from 2900 to 6730 as the thickness increased from 17.75 µm to 47.5 µm. The dissipation factor decreased from 0.27 to 0.06 with increasing thickness. This behavior was attributed to a low dielectric constant interfacial layer and a higher dielectric leakage current at smaller thicknesses. The dielectric constant increased from 1700 to 6350 and the dissipation factor decreased from 0.23 to 0.04 as the sintering temperature increased from 1150°C to 1300°C. This was attributed to an increase in tetragonality with grain size and a decrease in porosity with sintering temperature. Finally...

Electrophoretic deposition of BaTi0.85Zr0.15O3 nanopowders

Antonelli,Eduardo; Silva,Ronaldo Santos da; Bernardi,Maria Inês Basso; Hernandes,Antonio Carlos
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2013 EN
Relevância na Pesquisa
68.012817%
The present study reports the results of thick films (20-130 µm) produced through electrophoretic deposition of BaTi0.85Zr0.15O3 (BTZ) nanometric powders synthesized by the Pechini's method. The BTZ powderscalcined at 600°C/2h presented a single crystalline phase with an average particle size of ~20nm. To thick films deposition, a stable suspension of acetylacetone (Acac) and ethanol (EtOH)was prepared and the powder was deposited on platinum substrates. The viscosity of BTZ powders suspensions as a function of operational pH (OpH)was measured and the reactions between nanoparticles and the media were discussed. A milling process was used to deagglomerate the powders and it had a great influence in the suspension stability and deposition of thick films. Dense and crack-free thick films were obtained after sintering at 1220 °C/1h. The dielectric properties results, comparable with those of bulk BTZ ceramics, suggested potential applications of the EPD process for the deposition of ferroelectric/piezoelectric thick films.

Single-step electrochemical deposition of antimicrobial orthopaedic coatings based on a bioactive glass/chitosan/nano-silver composite system

Pishbin, F.; Mouriño, Viviana Silvia Lourdes; Gilchrist, J.; McComb, D.; Kreppel, S.; Salih, V.; Ryan, M. P.; Boccaccini, A. R.
Fonte: Elsevier Publicador: Elsevier
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
ENG
Relevância na Pesquisa
57.70855%
Composite orthopaedic coatings with antibacterial capability containing chitosan, Bioglass® particles (9.8ìm) and silver nanoparticles (Ag-np) were fabricated using a single-step electrophoretic deposition (EPD) technique, and their structural and preliminary in vitro bactericidal and cellular properties were investigated. Stainless steel 316 was used as a standard metallic orthopaedic substrate. The coatings were compared with EPD coatings of chitosan and chitosan/Bioglass®. The ability of chitosan as both a complexing and stabilizing agent was utilized to form uniformly deposited Ag-np. Due to the presence of Bioglass® particles, the coatings were bioactive in terms of forming carbonated hydroxyapatite in simulated body fluid (SBF). Less than 7wt.% of the incorporated silver was released over the course of 28days in SBF and the possibility of manipulating the release rate by varying the deposition order of coating layers was shown. The low released concentration of Ag ions (<2.5ppm) was efficiently antibacterial against Staphyloccocus aureus up to 10days. Although chitosan and chitosan/Bioglass® coating supported proliferation of MG-63 osteoblast-like cells up to 7days of culture, chitosan/Bioglass®/Ag-np coatings containing 342 ìg of Ag-np showed cytotoxic effects. This was attributed to the relatively high concentration of Ag-np incorporated in the coatings.; Fil: Pishbin...

Recubrimientos sol-gel obtenidos por deposición electroforética (EPD) sobre metales; Sol-gel coatings obtained from electrophoretic depositions (EPD) on metals

Ferrari, B.; Moreno Botella, Rodrigo María; Durán, A.; Castro Martín, Mª Yolanda
Fonte: Sociedad Española de Cerámica y Vidrio Publicador: Sociedad Española de Cerámica y Vidrio
Tipo: Artículo Formato: 668514 bytes; application/pdf
SPA
Relevância na Pesquisa
57.797876%
[ES] El proceso sol-gel es un método de gran interés para la producción de películas vítreas sobre metales, que actúan como barrera protectora frente a la oxidación y aumentan su resistencia a la corrosión. Se han obtenido recubrimientos inorgánicos e híbridos de distintas composiciones sobre distintos metales usando técnicas como inmersión, centrifugado y pulverización. Aunque estos métodos proporcionan recubrimientos con buenas propiedades los espesores obtenidos son bajos (inferiores a 2 mm), lo que limita sus posibilidades de aplicación. La deposición electroforética (EPD) se perfila como una técnica de gran versatilidad para la obtención de recubrimientos homogéneos de mayor espesor. El objetivo de este trabajo es la preparación de recubrimientos sobre metal por EPD a partir de soluciones híbridas de SiO2 (TEOS, MTES) y de suspensiones coloidales de SiO2 en las que las propias soluciones híbridas actúan como medio de dispersión. Tanto las soluciones como las suspensiones se han estudiado mediante medidas de viscosidad, densidad y conductividad. Asimismo, se han estudiado los parámetros físicos asociados a la EPD, tales como el tiempo de deposición y la densidad de corriente, teniendo en cuenta el efecto adicional de formación de capa por inmersión durante la extracción. Los recubrimientos se han caracterizado mediante perfilometría y microscopía óptica...

Thermogelation of composite films produced by electrophoretic codeposition

Ferrari, Begoña; Santacruz, Isabel; Nieto, María Isabel; Moreno, Rodrigo
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22528 bytes; application/msword
ENG
Relevância na Pesquisa
57.913896%
8 pages, 8 figures, 3 tables.; There is a growing interest to develop reliable, economic and environmentally-friendly methods for manufacturing thin and thick coatings and layered systems. Electrophoretic deposition has demonstrated to be a suitable technique for manufacturing laminates and coatings. For thick films, the adhesion to the substrate and the shape retention become important problems that lead to low density, cracking, and heterogeneous surfaces. To overcome these problems, a new idea is proposed consisting in the formation of a thick deposit by EPD in water and its immediate consolidation by thermogelation of polysaccharides, which is introduced in the suspension and forms a gel structure on cooling during withdrawal of the substrate from the suspension bath. In this work the parameters involved in the electrophoretic codeposition of two phase suspensions (Al2O3/Y-TZP) containing carrageenan, on non-porous graphite substrates are studied. Dense self-supported films with thickness between 10 and 500 μm are obtained after a thermal treatment in which the graphite substrate burns out and the subsequent sintering cycle. The performance of gel-deposition is studied as a function of the concentration of carrageenan, the solids loading and the electrical conditions.; This work has been supported by CICYT (Spain) under grant MAT2000-0949. Dr. B. Ferrari acknowledges CSIC and European Social Foundation for the concession of a contract I3P.; Peer reviewed

Electrophoretic deposition of monochrome and color phosphor screens for information displays

Talbot, J.B.; Sluzky, E.; Kurinec, Santosh
Fonte: Springer Netherlands - Journal of Materials Science Publicador: Springer Netherlands - Journal of Materials Science
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
67.797876%
This paper reviews our research on the electrophoretic deposition (EPD) of phosphors for the processing of monochromatic and color screens for information displays. Our investigation began with the study of the fundamentals of the EPD process for phosphors. The processing variables which enhance the adhesion strength of phosphor deposits were determined. The optical performance of phosphors deposited by EPD was shown to be not affected by the process itself nor by the conditions which enhance phosphor adhesion. Processes developed to produce high-resolution color screens by combining EPD and photolithography techniques are described. Also, a method to electrophoretically deposit phosphor in a thermo-reversible gel from mixtures of poly(butyl methacrylate) and isopropanol was examined.; RIT community members may access full-text via RIT Libraries licensed databases: http://library.rit.edu/databases/

Electrophoretic deposition of ferrite

Washburn, Cody
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado Formato: Hardbound
EN_US
Relevância na Pesquisa
68.244126%
The ability to integrate a material with a high permeability on chip, allows for magnetically coupled circuits and structures to be designed and incorporated along side CMOS circuitry. Devices ranging from A.C. transformers to magnetically driven MEMS structures can be designed and fabricated. Desirable characteristics of magnetic cores for integrated inductors and transformers are first high saturation flux in order to obtain high saturation current; high permeability to obtain high inductance; high resistivity to reduce eddy current loss at high frequencies and compatible deposition and patterning processes. High frequency magnetic materials are oxide based ceramics and are therefore difficult to evaporate, sputter, plate and selectively etched. ElectroPhoretic Deposition (EPD) is a method where insulating particles are imparted charge in a suspension and are made to deposit on an electrode by applying electric field. EPD has been extensively employed in depositing oxide based phosphors for display applications. In this study, ferrite particles have been prepared by grinding sintered toroids and deposited by EPD. The electrophoretic solution bath is composed of isopropyl alcohol with traces of Mg(N03)2 and La(N03)3 salts. Glycerol is added to the solution bath as a surfactant to promote increased substrate adhesion. The dissociation of magnesium nitrate in the solution bath charges the ferrite particles. An electric field of ~ 50-160 V/cm is applied with negative terminal connected to the wafer to be plated and aluminum electrode is used as the anode. The deposition process is found to be self limiting with the initial high elerophoretic current declining to 10% of its value in 10 minutes. The deposition rate and zeta potential measurements indicate a high particle velocity on the order 5.7x10-3 cm/s with an electric field of 160V/cm generated across the 2 cm electrode spacing. Pattern filling and conformal coverage in copper damascene planar microinductors has been investigated. A method to extracted permeability from S11 impedance analysis has been employed. It has been found that grinding process deteriorates magnetic response. With recent advances in magnetic particle technology for high frequency materials...

Electrophoretic deposition of a bioactive Si, Ca-rich glass coating on 316L stainless steel for biomedical applications

Rodríguez,H. H.; Maldonado-Reyes,A.; Cortés-Hernández,D. A.
Fonte: UNAM, Centro de Ciencias Aplicadas y Desarrollo Tecnológico Publicador: UNAM, Centro de Ciencias Aplicadas y Desarrollo Tecnológico
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 EN
Relevância na Pesquisa
68.09169%
This work consisted in the development and characterization of a vitroceramic coating on 316L stainless steel by means of electrophoretic deposition (EPD). This vitroceramic coating was obtained through a Si-, Ca-rich glass coating crystallization. The electrophoretic deposition tests were performed on 316L stainless steel mechanically polished substrates. The results suggest that the electrophoretic coatings adhered well to the metallic surfaces. The results demonstrate that the crystallized coatings are potentially bioactive, because a dense and homogeneous apatite layer, similar to a bone, makes up.