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Avaliação do pré-tratamento a base de sulfossiloxano sobre aço galvannealed combinado com tintas anticorrosivas.; Evaluation of sulfosilane pretreatment applied over galvannealed steel combined with anticorrosion coatings.

Francisco, Juliana Serafim
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 24/05/2013 PT
Relevância na Pesquisa
46.44%
Em 2012 foram gastos em torno de 80 bilhões de dólares com problemas relacionados à corrosão de materiais metálicos, entre eles custos diretos e indiretos em manutenções corretivas e preventivas. Esse elevado valor evidencia a importância de se trabalhar na proteção contra a corrosão. Há diversas maneiras de se mitigar os danos causados pelo fenômeno da corrosão em materiais metálicos, sendo uma delas o pré-tratamento dessas superfícies com camadas de conversão. O objetivo do presente trabalho é estudar o comportamento de um dos materiais mais utilizados na indústria automobilística, o aço galvannealed, depois de submetido a um pré-tratamento de superfície baseado na aplicação de um filme fino de sulfossilano seguido de pintura com tintas industriais. O desempenho do filme de silano foi comparado a um dos processos de pré-tratamento mais usuais do mercado brasileiro, que é a fosfatização. Após o desengraxe e limpeza do substrato com solução alcalina, o mesmo foi imerso por 15 minutos em uma solução de água e álcool (50/50 m/m) contendo 3% do silano bis-1,2-[trietoxisililpropil] tetrasulfeto (BTESPT), aditivada com 50 ppm de íons de Ce (IV). Depois de curar por 40 minutos a 150°C, obteve-se o filme de sulfossilano. Após o preparo dos corpos de prova com a aplicação do pré-tratamento...

Micromorphology and spectroscopic characteristics of organic matter in waterlogged podzols of the upper Amazon basin

Bardy, M.; Fritsch, E.; Derenne, S.; Allard, T.; do Nascimento, N. R.; Bueno, G. T.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 222-230
ENG
Relevância na Pesquisa
36.52%
In waterlogged environments of the upper Amazon basin, organic matter is a major driver in the podzolisation of clay-depleted laterites, especially through its ability to weather clay minerals and chelate metals. Its structure in eight organic-rich samples collected at the margin and in the centre of the podzolic area of a soil sequence was investigated. The samples illustrate the main steps in the development of waterlogged podzols and belong either to eluviated topsoil A horizons or to illuviated subsoil Bhs, Bh and 2BCs horizons. Organic matter micromorphology was described, and the overall molecular structure of their clay size fractions was assessed using Fourier transform infrared (FTIR) spectroscopy and cross polarization/magic angle spinning (CP/MAS) C-13 nuclear magnetic resonance (NMR). Organic features of the horizons strongly vary both vertically and laterally in the sequence. Topsoil A horizons are dominated by organic residues juxtaposed to clean sands with a major aliphatic contribution. In the subsoil, numerous coatings, characteristic of illuviation processes, are observed in the following horizons: (i) At the margin and bottom parts of the podzolic area, dark brown organic compounds of low aromacity with abundant oxygen-containing groups accumulate in Bhs and 2BCs horizons. Their spectroscopic features agree with the observation of cracked coatings in 2BCs and the presence of organometallic complexes...

Influence of cerium (IV) ions on the inorganic and organic phase for preparation of a siloxane-PMMA based film on tin plate substrate

Sarmento, V. H V; Diniz, R. N.; Benedetti, A. V.; Santilli, C. V.; Suegama, P. H.; Aoki, I. V.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 2138-2147
ENG
Relevância na Pesquisa
36.58%
Tinplate is one of the most widely used food canning materials, however, there are significant problems related to the use of tinplate cans, such as alterations in sensory features affecting food quality and corrosion phenomena of the canning material. To avoid corrosion problems different methods have been used for the passivation of tinplate such protective lacquers or different kinds of corrosion inhibitors (chromate and dichromate). However, chromates and dichromates are extremely harmful to the environment and can cause carcinogenic tumors to humans. An option, protective coatings obtained by the sol-gel process, act as a physical barrier, which isolates the surface of metal protecting from the corrosive agents. The aim of this work is to study the influence of addition of cerium (IV) ions in the inorganic and organic part of sol-gel processing in the formation of hybrid coatings based on siloxane-PMMA on tin plate. The coatings were obtained by dip-coating technique and evaluated by open circuit and impedance measurements, linear polarization and polarization curves obtained in 3.5% NaCl solution. The results have clearly shown the improvement on the protective properties of the Ce 4+ modified film when added into the organic phase...

Estabilidade de suco de maracuja acondicionado em embalagens de aço com diferentes revestimentos organicos.; Passion fruit juice stability conditioned in steel packings with different organic coverings.

Elisabete Segantini Saron
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/02/2004 PT
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46.39%
Este estudo teve por objetivo avaliar diferentes especificações de envernizamento interno do corpo e da costura lateral de latas de folha-de-flandres de três peças, formadas por eletrossolda, no acondicionamento de suco de maracujá pronto para beber, por meio de teste de estocagem e avaliação do desempenho em relação à interação embalagem/alimento. Durante o estudo foram avaliados três sistemas de revestimento orgânico interno da embalagem, sendo o primeiro composto de verniz epóxi-fenólico líquido aplicado na folha plana e verniz epóxi-vinílico-acrilado líquido aplicado na região da solda; o segundo um verniz epóxi-fenólico líquido aplicado na folha plana, verniz epóxi-vinílico-acrilado líquido aplicado na solda e uma segunda camada de verniz epóxi modificado líquido, aplicado por spray após a formação da lata e o terceiro um verniz líquido epóxi-fenólico aplicado na folha plana e verniz poliéster em pó aplicado na solda, denominados latas Normal, Repair e Pó, respectivamente. As embalagens foram caracterizadas quanto ao tipo de material metálico (espessura, dureza e camadas de estanho e cromo), avaliação do fechamento (recravação), atendimento aos requisitos de embalagens para contato com alimentos previstos pela Legislação Brasileira e pelo MERCOSUL e caracterização dos revestimentos orgânicos do corpo...

Organic-inorganic hybrid coatings for corrosion protection of galvanized steel and electroplated ZnFe steel

Souza, M. E. P.; Ariza, E.; Ballester, M.; Yoshida, I. V. P.; Rocha, L. A.; Freire, C. M. A.
Fonte: Associação Brasileira de Metalurgia e Materiais [etc.] Publicador: Associação Brasileira de Metalurgia e Materiais [etc.]
Tipo: Artigo de Revista Científica
Publicado em /05/2005 ENG
Relevância na Pesquisa
36.58%
The development of hybrids materials by the sol-gel process has been extensively investigated in recent years. The combination a wide variety of compositions and production processes had permit the use of these materials in different applications like coatings for corrosion protection of metals and abrasion resistant coatings. In this work organic-inorganic hybrid materials have been prepared from the hydrolysis of tetraethylorthosilicate (TEOS) and silanol-terminated polidymetilmetoxysilane (PDMS) using a sol-gel process. The composition evaluated was 50% TEOS- 50% PDMS. These materials have been applied on galvanized steel and on steel electroplated with a ZnFe alloy. In order to evaluate the degradation behaviour of these coatings, electrochemical techniques were used. They consisting in the monitoring of the open-circuit potential (Ecorr), and in the realization of potentiodynamic polarization measurements of the samples, which was performed in a 3% NaCl aqueous solution. Additionally, electrochemical impedance spectroscopy (EIS) was used as a complementary technique for the evaluation of the corrosion mechanisms of the coating system. The surface of the samples, before and after the electrochemical tests, have been inspected by SEM and EDS. EIS data was fitted to an equivalent circuit from which the electrochemical parameters were obtained. Results show a good protective character of the hybrid films...

Organic-inorganic hybrid coatings for corrosion protection of galvanized steel and electroplated znfe steel

Souza, M. E. P.; Ariza, E.; Ballester, M.; Yoshida, I. V. P.; Rocha, L. A.; Freire, C. M. A.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2004 ENG
Relevância na Pesquisa
36.58%
The development of hybrids materials by the sol-gel process has been extensively investigated in recent years. The combination a wide variety of compositions and production processes had permit the use of these aterials in different applications like coatings for corrosion protection of metals and abrasion resistant coatings. In this work organic-inorganic hybrid materials have been prepared from the hydrolysis of tetraethylorthosilicate (TEOS) and silanol-terminated polidymetilmetoxysilane (PDMS) using a sol-gel process. The composition evaluated was 50% TEOS- 50% PDMS. These materials have been applied on galvanized steel and on steel electroplated with a ZnFe alloy. In order to evaluate the degradation behaviour of these coatings, electrochemical techniques were used. They consisting in the monitoring of the open-circuit potential (Ecorr), and in the realization of potentiodynamic polarization measurements of the samples, which was performed in a 3% NaCl aqueous solution. Additionally, electrochemical impedance spectroscopy (EIS) was used as a complementary technique for the evaluation of the corrosion mechanisms of the coating system. The surface of the samples, before and after the electrochemical tests, have been inspected by SEM and EDS. EIS data was fitted to an equivalent circuit from which the lectrochemical parameters were obtained. Results show a good protective character of the hybrid films...

Influence of experimental parameters using the dip-coating method on the barrier performance of hybrid sol-gel coatings in strong alkaline environments

Figueira, R. B.; Silva, Carlos J. R.; Pereira, Elsa V.
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em //2015 ENG
Relevância na Pesquisa
36.5%
Previous studies have shown that the barrier effect and the performance of organic-inorganic hybrid (OIH) sol-gel coatings are highly dependent on the coating deposition method as well as on the processing conditions. However, studies on how the coating deposition method influences the barrier properties in alkaline environments are scarce. The aim of this experimental research was to study the influence of experimental parameters using the dip-coating method on the barrier performance of an OIH sol-gel coating in contact with simulated concrete pore solutions (SCPS). The influence of residence time (Rt), a curing step between each dip step and the number of layers of sol-gel OIH films deposited on hot-dip galvanized steel to prevent corrosion in highly alkaline environments was studied. The barrier performance of these OIH sol-gel coatings, named U(400), was assessed in the first instants of contact with SCPS, using electrochemical impedance spectroscopy and potentiodynamic methods. The durability and stability of the OIH coatings in SCPS was monitored during eight days by macrocell current density. The morphological characterization of the surface was performed by Scanning Electronic Microscopy before and after exposure to SCPS. Glow Discharge Optical Emission Spectroscopy was used to investigate the thickness of the U(400) sol-gel coatings as a function of the number of layers deposited with and without Rt in the coatings thickness.

FTIR, a powerful technique in organic coatings failure diagnosis

Costa, M. Rosário; Santos, M. Teresa; Diamantino, Teresa C.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Artigo de Revista Científica
Publicado em //2011 ENG
Relevância na Pesquisa
66.51%
FTIR spectrometry (Fourier Transform Infrared) is an instrumental technique of analysis that presents significant advantages on the dispersive traditional system, such as the increase of the relation signal-noise, the capacity of getting absorption spectra of low energy and therefore, bands of absorption of weak intensity. This technique is widely used in the study of resin characterization and evaluation of polymeric materials as well as degradation when polymers and coatings are exposed to various conditions of service, or still in the analysis and diagnosis of defects that occur during the application or production process. Techniques connected to the FTIR have appeared such as the photoacoustic (PAS-FTIR), the microscopy (MCT-FTIR) and the attenuated total reflectance (ATR), which allows to analysis of weekly transparent and dark samples without removal of coatings from the substrates. The choice of the technique to use depends on the morphology of the surfaces to analyze and the type of failure (lack of adhesion, contamination, aging degradation, etc). This work illustrates the application of FTIR and associated techniques to identify causes of diverse types of defects in applied organic coatings on polymeric materials.

Characterization of organic-inorganic hybrid coatings for corrosion protection of galvanized steel and electroplated ZnFe steel

Souza,Maria Eliziane Pires de; Ariza,Edith; Ballester,Margarita; Yoshida,Inez Valéria Pagotto; Rocha,Luis Augusto; Freire,Célia Marina de Alvarenga
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2006 EN
Relevância na Pesquisa
36.46%
The development of hybrids materials has been extensively investigated in recent years. The combination of a wide variety of compositions and production processes had permitted the use of these materials in different applications like coatings for corrosion protection of metals. In this work organic-inorganic hybrid materials have been prepared from the hydrolysis of tetraethylorthosilicate and silanol-terminated polidymetilmetoxysilane using a sol-gel process. These materials have been applied on galvanized steel and on steel electroplated with a ZnFe. In order to evaluate the degradation behavior of these coatings, electrochemical techniques (Electrochemical Impedance Spectroscopy and Potentiodynamic Polarization) were used. EIS data was fitted to an equivalent circuit from which the electrochemical parameters were obtained. Results show a good protective character of the hybrid films, when compared with uncovered specimens. The overall performance of the coating systems appears to be highly dependent on the kind of metallic coating applied to the steel.

Anticorrosive performance of commercial nanoceramic coatings on AISI 1010 steel

Kerstner,Estela Knopp; Kunst,Sandra Raquel; Beltrami,Lilian Vanessa Rossa; Vega,Maria Rita Ortega; Scienza,Lisete Cirstina; Malfatti,Célia de Fraga
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2014 EN
Relevância na Pesquisa
36.39%
The aim of this work was to study the corrosion behavior of three commercial nanoceramic coatings in comparison to zinc phosphate coatings applied on mild steel (SAE 1010). The coatings were evaluated by scanning electron microscopy (SEM), profilometry and hydrophobicity. The electrochemical behavior was evaluated by dynamic polarization. The results showed that the samples coated with nanoceramics presented contact angles greater than 100º, achieving hydrophobic behavior. Evaluating the electrochemical behavior under dynamic polarization revealed that the nanoceramic coating containing chromium (CHT) exhibited a higher corrosion potential and lower current than the other nanoceramic coatings tested, although its performance in a dilute sodium chloride solution was below that of the zinc phosphate-based coating. Although the nanoceramic coatings exhibited poor electrochemical behavior compared to the zinc-based coatings, they had a higher corrosion resistance when associated with an organic coating.

Microbial Penetration and Utilization of Organic Aircraft Fuel-Tank Coatings1

Crum, M. G.; Reynolds, R. J.; Hedrick, H. G.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1967 EN
Relevância na Pesquisa
36.55%
Microorganisms have been found as contaminants in various types of aircraft fuel tanks. Their presence introduces problems in the operation of the aircraft, including destruction of components such as the organic coatings used as protective linings in the fuel tanks. Microbial penetration and utilization of the currently used organic coatings, EC 776, DV 1180, PR 1560, and DeSoto 1080, were determined by changes in electrical resistances of the coatings; mycelial weight changes; growth counts of the bacteria; and manometric determinations on Pseudomonas aeruginosa (GD-FW B-25) and Cladosporium resinae (QMC-7998). The results indicate EC 776 and DV 1180 to be less resistant to microbial degradation than the other coatings. Organic coatings, serving as a source of nutrition, would be conducive to population buildups in aircraft fuel tanks.

Organic electrode coatings for next-generation neural interfaces

Aregueta-Robles, Ulises A.; Woolley, Andrew J.; Poole-Warren, Laura A.; Lovell, Nigel H.; Green, Rylie A.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 27/05/2014 EN
Relevância na Pesquisa
36.5%
Traditional neuronal interfaces utilize metallic electrodes which in recent years have reached a plateau in terms of the ability to provide safe stimulation at high resolution or rather with high densities of microelectrodes with improved spatial selectivity. To achieve higher resolution it has become clear that reducing the size of electrodes is required to enable higher electrode counts from the implant device. The limitations of interfacing electrodes including low charge injection limits, mechanical mismatch and foreign body response can be addressed through the use of organic electrode coatings which typically provide a softer, more roughened surface to enable both improved charge transfer and lower mechanical mismatch with neural tissue. Coating electrodes with conductive polymers or carbon nanotubes offers a substantial increase in charge transfer area compared to conventional platinum electrodes. These organic conductors provide safe electrical stimulation of tissue while avoiding undesirable chemical reactions and cell damage. However, the mechanical properties of conductive polymers are not ideal, as they are quite brittle. Hydrogel polymers present a versatile coating option for electrodes as they can be chemically modified to provide a soft and conductive scaffold. However...

An approach to design new coatings for biomedical applications

El-Hadad, Amir Abdel-Samie
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: Tese de Doutorado Formato: application/pdf
ENG
Relevância na Pesquisa
36.73%
Ti6Al4V alloy is widely used as implants for orthopedic and dental applications because of its superior mechanical properties, excellent corrosion resistance and good biocompatibility. However, it takes long period of several months for Ti6Al4V implants to integrate with the bone tissue due to their bio-inert feature in nature. An innovating and incipient method to solve the above mentioned drawbacks consist of the development of new coatings which could improve both the biological and corrosion protection performance of the Ti6Al4V alloy. Thus, a variety of strategies have been implemented to modify the surface of Ti6Al4V-based implants and enhance bone growth and their initial stability. A common approach is the deposition of bioactive hybrid coatings including inorganic and organic units on the surface of the Ti6Al4V alloy via sol-gel method. The sol–gel route is of great interest as it offers the possibility of tailoring the material properties by variation of the relative composition of the precursors used. The aim of this thesis is focused on the development of new coatings, starting with inorganic hydroxyapatite (HAp) deposited onto Ti6Al4V substrate prepared through solgel route. The effect of thermal treatment temperature on both in-vitro bioactivity and corrosion performance has been studied in simulated body fluid solution (SBF). A complete physical-chemical characterization was done in all the thermally treated coatings obtained. In-vitro tests in SBF were carried out in order to investigate the biological performance of the films. Due to the high temperature required for synthesizing HAp in crystalline form...

Triethylphosphite as a network forming agent enhances in-vitro biocompatibility and corrosion protection of hybrid organic-inorganic sol-gel coatings for Ti6Al4V alloys

El Hadad, Amir; Barranco, V.; Jiménez Morales, Antonia; Hickman, G. J.; Galván, J. C.; Perry, C. C.
Fonte: Royal Society of Chemistry Publicador: Royal Society of Chemistry
Tipo: info:eu-repo/semantics/acceptedVersion; info:eu-repo/semantics/article
Publicado em /10/2014 ENG
Relevância na Pesquisa
36.54%
The biocompatibility and life of metallic implants can be enhanced through improving the biocompatibility and corrosion protection characteristics of the coatings used with these materials. In this study, triethylphosphite (TEP) was used to introduce phosphorus into organic-inorganic hybrid silica based sol-gel coatings prepared using gamma-methacryloxypropyltrimethoxysilane and tetramethylorthosilicate. Addition of TEP dramatically increased the rate of intermolecular condensation and resulted in materials showing greater cross-linking. Protein (fibrinogen) uptake, osteoblast in vitro biocompatibility and corrosion resistance was enhanced in coatings containing TEP. Although higher concentrations of phosphorus supported the greatest improvement in biocompatibility, a compromise in the phosphorus concentration used would be required if corrosion resistance was most desirable parameter for optimisation. Films prepared by dip coating on Ti6Al4V alloys from these sols offer a promising alternative to wholly metallic prostheses.; This work was supported by the Ministerio de Economía y Competitividad (Project MAT2012-30854).; In Press, Accepted Manuscript

Organic coatings deterioration: Mean models and quantification methods; Deterioro de recubrimientos orgánicos: Principales modelos y métodos de cuantificación

Angela Bermudez Castañeda; Universidad de Antioquia; Juan Guillermo Castaño-González; Universidad de Antioquia; Félix Echeverría Echeverría; Universidad de Antioquia
Fonte: Universidad del Norte Publicador: Universidad del Norte
Tipo: article; publishedVersion Formato: application/pdf
SPA
Relevância na Pesquisa
46.33%
Paints are the main protection method for atmospheric deterioration of metallic structures. Their performance in service depends largely on the nature of organic coatings and environmental and meteorological factors. For these reasons, it is essential for development, selection and evaluation of paints to identify the deterioration phenomenology as well as the methods used for modeling and predicting the behavior of coatings, the preventive maintenance o replacement dates and the life time of repaired structures. In this review the main employed methods used for the modeling of such deterioration for predictive purposes are presented.;  Las pinturas constituyen uno de los principales métodos de protección contra el deterioro atmosférico de estructuras metálicas. El desempeño en servicio de las mismas depende en gran medida de la naturaleza de los recubrimientos orgánicos y del efecto de diversos factores ambientales y meteorológicos. Por esta razón, es esencial tanto para el desarrollo de nuevos recubrimientos como para los procesos de evaluación de pinturas identificar la fenomenología del deterioro, así como los métodos usados para modelar y predecir el comportamiento de los recubrimientos, las fechas de mantenimiento preventivo o reemplazo...

Influencia de las condiciones de preparación en la luminiscencia de recubrimientos de sílice pura; Influence of preparating conditions on the luminescence of pure silica coatings

Villegas Broncano, María Ángeles; García, Miguel Ángel Pérez; Llopis, J.; Paje, S. E.
Fonte: Sociedad Española de Cerámica y Vidrio Publicador: Sociedad Española de Cerámica y Vidrio
Tipo: Artículo Formato: 347111 bytes; application/pdf
SPA
Relevância na Pesquisa
36.34%
[ES] Los recubrimientos de SiO2 preparados mediante la técnica sol-gel, presentan una luminiscencia en la zona UV-Visible del espectro con un máximo centrado en torno a 3,4 eV (365 nm). El espectro de emisión puede descomponerse en dos bandas de perfil gausiano, centradas en 3,35 eV (370 nm) y 3,0 eV (415 nm), respectivamente. El espectro de excitación correspondiente a esta emisión presenta una banda centrada en 3,85 eV (320 nm). Con objeto de clarificar el origen de esta luminiscencia se ha realizado el estudio según los precursores utilizados en la preparación de los recubrimientos y el efecto que los tratamientos térmicos de densificación tienen sobre la luminiscencia. Asimismo, se ha comprobado que la presencia de materia orgánica en los recubrimientos antes de ser densificados modifica las propiedades luminiscentes de los mismos. Por tanto, ciertas variaciones en el espectro de la luminiscencia podrían interpretarse como indicativas de un cierto cambio en el contenido de restos orgánicos en el recubrimiento, así como de posibles variaciones del contenido en exceso de oxígeno.; [EN] SiO2 coatings prepared by sol-gel technique show an UV-Visible luminescence with a maximum centered at about 3.4 eV (365 nm). The emission spectrum can be decomposed into two Gaussian shape bands...

Novel Organic Heterostructures Enabled by Emulsion-Based, Resonant Infrared, Matrix-Assisted Pulsed Laser Evaporation (RIR-MAPLE)

McCormick, Ryan
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2014
Relevância na Pesquisa
36.39%

An explosion in the growth of organic materials used for optoelectronic devices is linked to the promise that they have demonstrated in several ways: workable carrier mobilities, ease of processing, design flexibility to tailor their optical and electrical characteristics, structural flexibility, and fabrication scalability. However, challenges remain before they are ready for prime time. Deposition of these materials into ordered thin films requires that they be cast from solutions of organic solvents. Drawbacks of solution-casting include the difficulty of producing layered films without utilizing orthogonal solvents (or even with orthogonal solvents), the difficulty in controlling domain sizes in films of mixed materials, and the lack of parameter options used to control the final properties of thin films. Emulsion-based, resonant infrared, matrix-assisted pulsed laser evaporation (RIR-MAPLE) is a thin film deposition technique that is demonstrated to provide solutions to these problems.

This work presents fundamental research into the RIR-MAPLE process. An investigation of the molecular weight of deposited materials demonstrates that emulsion-based RIR-MAPLE is capable of depositing polymers with their native molecular weights intact...

FTIR, a powerful technique in organic coatings failure diagnosis

Costa, Maria do Rosário; Santos, M. Teresa; Diamantino, Teresa C.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em 08/09/2009 ENG
Relevância na Pesquisa
46.46%
FTIR spectrometry (Fourier Transform Infrared) is an instrumental technique of analysis that presents significant advantages on the dispersive traditional system, such as the increase of the relation signalnoise, the capacity of getting absorption spectra of low energy and therefore, bands of absorption of weak intensity. This technique is widely used in study, resin characterization and evaluation of polymeric materials as well as of its degradation when exposed to the most varied conditions of service, or still in the analysis and diagnosis of defects that occur during the application or production process. Techniques connected to the FTIR had more recently appeared as the photoacoustic (PAS-FTIR), the microscopy (MCT-FTIR) and the attenuated total reflectance (ATR), which allow to analyze weekly transparent and dark samples without removal of coatings from the substrates. The choice of the technique to use depends on the morphology of the surfaces to analyze and the type of failure in cause (lack of adhesion, contamination, aging degradation, etc). In this work the application of FTIR and techniques associates to the identification of the causes that had originated diverse types of defect in applied organic coatings on polymeric materials is presented. Key words: FTIR...

BARRIER PROPERTY DETERMINATION AND LIFETIME PREDICTION BY ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY OF A HIGH PERFORMANCE ORGANIC COATING

CALDERÓN-GUTIERREZ,JORGE ANDRÉS; BEDOYA-LORA,FRANKY ESTEBAN
Fonte: DYNA Publicador: DYNA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2014 EN
Relevância na Pesquisa
46.08%
The anticorrosion performance of an Epoxy-Mastic organic coating was evaluated during continuous immersion in saline solution using electrochemical impedance spectroscopy (EIS). The typical parameters of pore resistance and charge transfer resistance were determined employing an equivalent electric circuit. Constant phase elements (CPE) were used in order to determine fraction of water absorbed, mass diffusion, solubility and the swelling coefficients, as well as to predict the failure times of the coating. The results found by EIS measurements match very well with the high resistance to deterioration exhibited by the coating. It was also found that the excellent protection performance of the coating was mainly due to low water solubility and low permeability.

Characterization and Development of Organic Coatings for Steel Rebars in Concrete

Selvaraj,R.; Bhuvaneshwari,B.
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
Relevância na Pesquisa
56.44%
Corrosion of the embedded steel reinforcements (rebars) in concrete is the major reason for the deterioration of concrete structures. One of the effective methods of overcoming this serious problem is by applying a barrier coating to the steel rebars. The barrier coating on steel rebars isolates the steel from the immediate environment and also acts as an insulator to prevent the corrosion. Four different coatings have been formulated using resins such as epoxy silicone-polyamide, polyester polyol-aromatic isocyanate, and acrylic polyol-aromatic isocyanate. These formulations consist of either ordinary portland cement (OPC) or fly ash as extender (pozzolanic pigments) and titanium dioxide (TiO2) and zinc phosphate as the main pigment. All these coatings have been studied for their barrier protection and other mechanical properties. Evaluation study of these coatings include Electrochemical Impedance Spectroscopy (EIS), chemical resistance tests and mechanical tests such as flexibility, impact resistance, adhesion, hardness and abrasion resistance, etc., as per ASTM standards and the results are discussed elaborately. It has been concluded from this study that the epoxy silicone-polyamide resin based coating formulation shows good mechanical properties in addition to the barrier protection to the steel rebars from the corrosive environments.