Síntesis y caracterización de pinturas selectivas de Co3O4 para superficies selectivas en colectores solares de baja temperatura

Para aumentar el rendimiento energético de los calefones solares se recubre al colector con superficies selectivas, donde las pinturas selectivas representan una alternativa económica. El Co3O4 utilizado como pigmento en pinturas selectivas se ha obtenido por diferentes métodos, pero mediante síntesis por combustión se han encontrado pocas referencias respecto a la temática. Se obtuvieron micropartículas de Co3O4 mediante una vía de combustión. Luego, por Difracción de Rayos X se determinó la estructura cúbica del Co3O4, además, por Microscopía Electrónica de Barrido, se observó una morfología compacta y aglomeración y mediante Microscopía Electrónica de Transmisión se apreciaron tamaños de partícula de 1m aprox. La absorbancia espectral en un rango de 500 a 1100 nm de longitud de onda de las películas formadas a partir de los pigmentos de Co3O4 sobre vidrio y aluminio está entre 0.92 y 0.96 menor al obtenido para una pintura comercial que está entre 0.95 y 0.97.Fil: Gardey Merino, María Celeste. Universidad Tecnológica Nacional, Facultad Regional Mendoza, CLIOPE,; ArgentinaFil: Belda, R.. Universidad Tecnológica Nacional, Facultad Regional Mendoza, CLIOPE,; ArgentinaFil: Lascalea, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Reg. de Invest. Cientif. y Tecnológicas. Laboratorio de Invest. y Servicios Ambientales Mendoza; ArgentinaFil: Vazquez, Patricia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentin

Síntese e caracterização de CaZrO3 e BaZrO3 nanoestruturados

SYNTHESIS AND CHARACTERIZATION OF NANOSTRUCTURED CaZrO3 AND BaZrO3. In this work, nanostructured samples of barium zirconate (BaZrO3) and calcium zirconate (CaZrO3) were synthesized by the gel-combustion method, using glycine as fuel. The ceramic powders were calcined at 550 °C for 2 h and subsequently heat treated at 1350 °C for 10 min (fast-firing). The X-ray diffraction technique was employed to identify and characterize the crystalline phases present in the synthesized powders, using the Rietveld method. Monophasic nanostructured samples of BaZrO3 and CaZrO3 presenting average crystallite sizes of around 8.5 and 10.3 nm, respectively, were found after fast-firing.Fil: Ibiapino, Amanda Laura. Universidade Federal do Mato Grosso Do Sul; Brasil;Fil: Pires de Figueiredo, Laysa. Universidade Federal do Mato Grosso Do Sul; Brasil;Fil: Lascalea, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Mendoza; Argentina;Fil: Junqueira Prado, Rogério. Universidade Federal do Mato Grosso Do Sul; Brasil

Synthesis and characterization of Co3O4 nanoparticles for use as pigments in solar absorbing paints

This aim of this research is to produce Co3O4 oxide by means of one-step solution novel combustion methods usingaspatic acid (C4H7NO4); lysine (C6H14N2O2); tris (hydroximethyl) aminomethane (NH2C (CH2OH)3) and ethylene diaminetetra-acetic acid (C10H16N2O8) as fuels. The pigments were characterized using X-ray diffraction, scanning andtransmission electron microscopy, infrared spectroscopy with Fourier transform and UV-VIS-IR Spectrophotometry.The paint based on alkyd resin was made from pigments obtained (Co3O4 oxide). In order to make a comparison of thethermal emittance of the paint, two different formulations were prepared and these coating are named "absorbent paintcoating": one that included 1% by weight of aluminum in metallic powder and another, with 1% of copper in metallicpowder, respectively. The solar absorbance for the Co3O4 powders, plus quartz cuvette, gave a value of 0.9 in all cases.An extraordinary value of absorption on the coatings between 95 and 96% was noted. These results suggested that thesynthesis of combustion in solution makes it possible to obtain a Co3O4 absorbent pigment with different fuels.These syntheses have a low environmental impact because they are one-step processes. All use low amounts of reactiveash obtained at a calcination of about 500 °C. These results suggest the possibility of utilizing this oxide in absorbentsolar paints.Fil: Gardey Merino, María Celeste. Universidad Tecnológica Nacional. Facultad Regional Mendoza. Grupo CLIOPE. Energía, Ambiente y Desarrollo Sustentable; ArgentinaFil: Rodriguez Ibarra, Mariana Estela. Universidad Tecnológica Nacional. Facultad Regional Mendoza. Grupo CLIOPE. Energía, Ambiente y Desarrollo Sustentable; ArgentinaFil: Lascalea, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Vazquez, Patricia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentin

Combustion synthesis of Co-Cu-Mn oxides deploying different fuels

Ternary spinel-like oxides such as CuFeMnO4, CoCuMnOxand CuCr2O4are attractive materials due to their absorbent properties when used as pigments for selective surfaces thus improving solar heaters efficiency. These materials are obtained through sol-gel and sol-gel-combustion methods. This work proposes the synthesis of mixed oxides of Co, Cu and Mn by means of original one-step stoichiometric combustion methods starting from Mn(NO3)2,Co(NO3)26H2O, Cu(NO3)23H2O and Aspartic acid (Asp) or Lysine(Lys) as fuels. The resulting ashes after the combustion were calcined at 500 °C. The obtained ashes and the calcined powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and by Brunauer–Emmett– Teller method (BET), and TG-DTA analysis. In calcined powders obtained with Lys (CoCuMnOx-Lys), the phase corresponding to CoCuMnOxand others segregated phases were identified. However, in calcined powders obtained with Asp (CoCuMnOx-Asp) only the phase corresponding to CoCuMnOxwas identified. The sample CoCuMnOx-Lys presented an average crystallite size of 44 nm and a specific surface area of 23 m2/g while in CoCuMnOx-Asp, 54 nm and 13 m2/g values were obtained throughout FT-IR vibrational modes associated with spinel metallic oxides for both calcined powders (Asp and Lys) were observed. Additionally, by means of TEM, polyhedral particles with an average size of 20 to 100 nm were observed. In particular, it was determined in CoCuMnOx-Lys an average size of 44nm. According to the different fuels used (Asp and Lys), an evident variation in the obtained phases was observed. However, it was not obtained any difference in crystallite size and specific area surface values. It is of considerable importance the study of further syntheses processes to verify this trend.Centro de Investigación y Desarrollo en Ciencias Aplicada

Combustion synthesis of Co-Cu-Mn oxides deploying different fuels

Ternary spinel-like oxides such as CuFeMnO4, CoCuMnOxand CuCr2O4are attractive materials due to their absorbent properties when used as pigments for selective surfaces thus improving solar heaters efficiency. These materials are obtained through sol-gel and sol-gel-combustion methods. This work proposes the synthesis of mixed oxides of Co, Cu and Mn by means of original one-step stoichiometric combustion methods starting from Mn(NO3)2,Co(NO3)26H2O, Cu(NO3)23H2O and Aspartic acid (Asp) or Lysine(Lys) as fuels. The resulting ashes after the combustion were calcined at 500 °C. The obtained ashes and the calcined powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and by Brunauer–Emmett– Teller method (BET), and TG-DTA analysis. In calcined powders obtained with Lys (CoCuMnOx-Lys), the phase corresponding to CoCuMnOxand others segregated phases were identified. However, in calcined powders obtained with Asp (CoCuMnOx-Asp) only the phase corresponding to CoCuMnOxwas identified. The sample CoCuMnOx-Lys presented an average crystallite size of 44 nm and a specific surface area of 23 m2/g while in CoCuMnOx-Asp, 54 nm and 13 m2/g values were obtained throughout FT-IR vibrational modes associated with spinel metallic oxides for both calcined powders (Asp and Lys) were observed. Additionally, by means of TEM, polyhedral particles with an average size of 20 to 100 nm were observed. In particular, it was determined in CoCuMnOx-Lys an average size of 44nm. According to the different fuels used (Asp and Lys), an evident variation in the obtained phases was observed. However, it was not obtained any difference in crystallite size and specific area surface values. It is of considerable importance the study of further syntheses processes to verify this trend.Centro de Investigación y Desarrollo en Ciencias Aplicada

Combustion synthesis of Co-Cu-Mn oxides deploying different fuels

Ternary spinel-like oxides such as CuFeMnO4, CoCuMnOxand CuCr2O4are attractive materials due to their absorbent properties when used as pigments for selective surfaces thus improving solar heaters efficiency. These materials are obtained through sol-gel and sol-gel-combustion methods. This work proposes the synthesis of mixed oxides of Co, Cu and Mn by means of original one-step stoichiometric combustion methods starting from Mn(NO3)2,Co(NO3)26H2O, Cu(NO3)23H2O and Aspartic acid (Asp) or Lysine(Lys) as fuels. The resulting ashes after the combustion were calcined at 500 °C. The obtained ashes and the calcined powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and by Brunauer–Emmett– Teller method (BET), and TG-DTA analysis. In calcined powders obtained with Lys (CoCuMnOx-Lys), the phase corresponding to CoCuMnOxand others segregated phases were identified. However, in calcined powders obtained with Asp (CoCuMnOx-Asp) only the phase corresponding to CoCuMnOxwas identified. The sample CoCuMnOx-Lys presented an average crystallite size of 44 nm and a specific surface area of 23 m2/g while in CoCuMnOx-Asp, 54 nm and 13 m2/g values were obtained throughout FT-IR vibrational modes associated with spinel metallic oxides for both calcined powders (Asp and Lys) were observed. Additionally, by means of TEM, polyhedral particles with an average size of 20 to 100 nm were observed. In particular, it was determined in CoCuMnOx-Lys an average size of 44nm. According to the different fuels used (Asp and Lys), an evident variation in the obtained phases was observed. However, it was not obtained any difference in crystallite size and specific area surface values. It is of considerable importance the study of further syntheses processes to verify this trend.Centro de Investigación y Desarrollo en Ciencias Aplicada

Síntesis y caracterización de pinturas selectivas de CoCuMnOx para pinturas absorbentes solares

En este trabajo se propone estudiar la obtención de óxidos mixtos tipo espinela como CoMnCuOx mediante síntesis por combustión estequiométrica originales de un solo paso utilizando ácido aspártico como combustible y la preparación de una pintura absorbente con estos óxidos. Los polvos obtenidos se calcinaron a 500°C y se caracterizaron mediante Difracción de Rayos X, Microscopía Electrónica de Barrido y de Transmisión, además las propiedades ópticas de la pintura se estudiaron mediante reflectometría. Como resultado se obtuvieron partículas aglomeradas y poligonales de CoCuMnO₄ de un tamaño aproximado entre 20 y 100nm. En superficies de aluminio pintadas con la pintura absorbente se logró una absorción solar del 96,5% entre 500 y 1000nm de longitud de onda y temperaturas promedios mayores en comparación con superficies pintadas con aerosol comercial, expuestas al sol. Entonces, con estos valores de altos valores de absorción, se sugiere el uso de estos pigmentos en pinturas absorbentes solares.This work is aimed to study the production of mixed oxides spinel type as CoMnCuOx by means of original one-step stoichiometric combustion methods using aspartic acid as fuel and elaboration of absorbent enamel with these oxides. Once obtained the ashes from the combustion processes, they were calcined at 500°C. The obtained powders were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and optical properties of enamels were analyzed by reflectometry. As a results agglomerated, polygonal nano-particles of CoCuMnO₄ with a particle size between 20 and 100 nm were obtained. Aluminum surfaces painted with absorbent enamel resulted with a solar absorption of 96,5% between 500 and 1000 nm length wave and average temperatures higher than surfaces with painted with an commercial aerosol. Then, considering these high absorption values suggest the possibility of utilizing these oxides as active pigments, in absorbent solar enamels.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Síntesis y caracterización de pinturas selectivas de CoCuMnOx para pinturas absorbentes solares

En este trabajo se propone estudiar la obtención de óxidos mixtos tipo espinela como CoMnCuOx mediante síntesis por combustión estequiométrica originales de un solo paso utilizando ácido aspártico como combustible y la preparación de una pintura absorbente con estos óxidos. Los polvos obtenidos se calcinaron a 500°C y se caracterizaron mediante Difracción de Rayos X, Microscopía Electrónica de Barrido y de Transmisión, además las propiedades ópticas de la pintura se estudiaron mediante reflectometría. Como resultado se obtuvieron partículas aglomeradas y poligonales de CoCuMnO₄ de un tamaño aproximado entre 20 y 100nm. En superficies de aluminio pintadas con la pintura absorbente se logró una absorción solar del 96,5% entre 500 y 1000nm de longitud de onda y temperaturas promedios mayores en comparación con superficies pintadas con aerosol comercial, expuestas al sol. Entonces, con estos valores de altos valores de absorción, se sugiere el uso de estos pigmentos en pinturas absorbentes solares.This work is aimed to study the production of mixed oxides spinel type as CoMnCuOx by means of original one-step stoichiometric combustion methods using aspartic acid as fuel and elaboration of absorbent enamel with these oxides. Once obtained the ashes from the combustion processes, they were calcined at 500°C. The obtained powders were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and optical properties of enamels were analyzed by reflectometry. As a results agglomerated, polygonal nano-particles of CoCuMnO₄ with a particle size between 20 and 100 nm were obtained. Aluminum surfaces painted with absorbent enamel resulted with a solar absorption of 96,5% between 500 and 1000 nm length wave and average temperatures higher than surfaces with painted with an commercial aerosol. Then, considering these high absorption values suggest the possibility of utilizing these oxides as active pigments, in absorbent solar enamels.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Óxidos nanoestructurados de silicio y cobalto para pinturas solares: Síntesis de óxidos nanoestructurados de aluminio, cobalto y silicio para superficies selectivas de colectores solares

Se trabajó en síntesis por Gelificación Combustión y caracterización de nanopartículas de Al2O3 y Co3O4 mediante rutas estequiométrica y con exceso de combustible; obtención y caracterización de óxidos mixtos de Co-Si mediante síntesis sol-gel y, obtención y caracterización de prototipos de superficies selectivas formadas por superficies metálicas recubiertas con pinturas absorbedoras solares.Los polvos de Co3O4 resultaron tener una alta absorbancia solar y se decidió utilizarlos para la fabricación de pinturas absorbedoras con resinas polivinílicas y alquídicas, en ambos casos, se lograron valores altos de absorción solar, sin embargo las alquídicas resultaron tener una mayor adhesión y una terminación más uniforme. Los valores de absorción solar y emitancia térmica resultaron altos para las superficies selectivas obtenidas al aplicar las pinturas alquídicas sobre sustratos metálicos. Los altos valores de emitancia térmica se asocian con el espesor relativamente alto de las capas de pinturas. Con espesores de pinturas menores, o el agregado de partículas metálicas, podrían obtenerse valores de emitancia mucho más bajos.Fil: Gardey Merino, María Celeste. Universidad Tecnológica Nacional. Facultad Reg.mendoza. Centro de Estudio Para El Desarrollo Sustentable; Argentina. Universidad Nacional de La Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lascalea, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Vázquez, Patricia. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; Argentin