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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Pigmentos a base de Cobalto para aplica??o em revestimentos cer?micos

Costa, Asenete Frutuoso da 18 August 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-11-27T13:08:55Z No. of bitstreams: 1 AseneteFrutuosoDaCosta_TESE.pdf: 4115238 bytes, checksum: 72a04780a21fa7344d83533cdbdd3d36 (MD5) / Approved for entry into archive by Elisangela Moura (lilaalves@gmail.com) on 2015-11-27T14:44:06Z (GMT) No. of bitstreams: 1 AseneteFrutuosoDaCosta_TESE.pdf: 4115238 bytes, checksum: 72a04780a21fa7344d83533cdbdd3d36 (MD5) / Made available in DSpace on 2015-11-27T14:44:06Z (GMT). No. of bitstreams: 1 AseneteFrutuosoDaCosta_TESE.pdf: 4115238 bytes, checksum: 72a04780a21fa7344d83533cdbdd3d36 (MD5) Previous issue date: 2014-08-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Dentre os principais pigmentos, os materiais cer?micos que possuem a estrutura espin?lio AB2O4 v?m se tornando objeto de grande interesse cient?fico e tecnol?gico devido ? capacidade em acomodar diferentes c?tions em sua estrutura, permitindo diferentes tipos dopagens e, consequentemente, a obten??o de diferentes cores. Estudos sobre pigmentos cer?micos, atualmente, v?m sendo direcionados para o desenvolvimento de pigmentos est?veis e obtidos a baixas temperaturas e com maior reprodutibilidade. O objetivo do seguinte estudo ? a utiliza??o de pigmentos inorg?nicos para aplica??es em revestimentos cer?micos, tentando compreender quais par?metros influenciam na colora??o do pigmento nos esmaltes cer?micos. Pigmentos a base de CoCr2O4, CoAl2O4, Co0,8Zn0,2Cr2O4 e Co0,8Zn0,2Al2O4Co/Cr, foram sintetizados por uma rota qu?mica usando gelatina como precursor org?nico. Tais pigmentos foram caracterizados por An?lise termogravim?trica, Difra??o de raios X (DRX), Espectroscopia na regi?o do Infravermelho, Microscopia eletr?nica de varredura (MEV) Espectroscopia na regi?o do UV-Vis?vel e Colorimetria. Os resultados confirmaram a viabilidade da rota de s?ntese utilizada; com rela??o aos p?s sintetizados, Os pigmentos mostraram-se cristalinos e as fases desejadas foram obtidas a partir de 500oC, com um aumento da cristalinidade, assim como o tamanho m?dio de cristalito. Os pigmentos possuem tonalidades que v?o do verde ao violeta de acordo com as dopagens e suas temperaturas de calcina??o. / Ceramic pigments that own mainly the spinel structure AB2O4 are becoming a matter of great scientific and technological interest due to the ability of accommodate different cations in its structure, allowing different dopings and thus obtaining different colors. Studies on ceramic pigments currently are being directed to the development of stable and pigments obtained at low temperatures and with greater reproducibility. This work aims at the use of inorganic pigments for applications in ceramic tiles, investigating the influence of doping and calcination temperature on the coloring pigments and ceramic glazes. the based pigments of CoCr2O4, CoAl2O4, Co0,8Zn0,2Cr2O4 and Co0,8Zn0,2Al2O4 were synthesized by a chemical route using commercial gelatin as organic precursor. The materials were characterized by thermogravimetric analysis (TG), X-ray diffraction (XRD), infrared spectroscopy (FTIR) spectroscopy scanning electron microscopy (SEM) in the UVVisible region and colorimetry. The results confirmed the feasibility of synthesis used, the route presented pigments crystal structures and the desired phases were obtained from 500 ?C with increased crystallinity and the crystallite size. The pigments have hues ranging from green to violet according to their doping and calcination temperatures.
2

Pigmentos a base de xisto retortado impregnado com metais para aplica??o em esmaltes cer?micos / Pigments based on shale impregnated with metals for application in ceramic enamels

Silva, Maria de F?tima Dantas e 01 September 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-11-22T20:18:43Z No. of bitstreams: 1 MariaDeFatimaDantasESilva_TESE.pdf: 4790020 bytes, checksum: 76003788c17fef9645769d5d4a851b01 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-11-23T00:20:06Z (GMT) No. of bitstreams: 1 MariaDeFatimaDantasESilva_TESE.pdf: 4790020 bytes, checksum: 76003788c17fef9645769d5d4a851b01 (MD5) / Made available in DSpace on 2017-11-23T00:20:06Z (GMT). No. of bitstreams: 1 MariaDeFatimaDantasESilva_TESE.pdf: 4790020 bytes, checksum: 76003788c17fef9645769d5d4a851b01 (MD5) Previous issue date: 2017-09-01 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Assim como a maioria dos setores industriais, o setor cer?mico tamb?m sentiu a necessidade de desenvolvimento. Desta forma, a ind?stria cer?mica vem buscando cada vez mais novos pigmentos para a produ??o de pisos e revestimentos, visando atender a demanda de cer?micas para decora??o de ambientes, tanto dom?sticos quanto comerciais. Al?m disso, h? um grande interesse em desenvolver novos materiais que estejam de acordo com a preserva??o ambiental e que tamb?m sejam relativamente de baixo custo. O xisto retortado (XR) ? um rejeito proveniente da ind?stria do xisto que, armazenado de forma inadequada, pode causar danos ? sa?de e ao meio ambiente.O objetivo deste estudo ? avaliar a viabilidade desse material, xisto retortado puro e xisto retortado impregnado com metais, na obten??o de pigmentos que colorem, de forma est?vel, diversas matrizes cer?micas; tentando compreender quais par?metros influenciam na pigmenta??o dos esmaltes. Os pigmentos a base de XR foram preparados impregnando os metais por via ?mida e calcinados a 700 e 900?C. Em seguida foram caracterizados por Fluoresc?ncia de Raio X (FRX) An?lise termogravim?trica (Tg), Difra??o de raios X (DRX), Espectroscopia na regi?o do Infravermelho (FTIR), Microscopia eletr?nica de varredura (MEV/EED), Espectroscopia na regi?o do UV-Vis?vel e Colorimetria. Os resultados confirmam a viabilidade do uso do xisto como pigmento cer?mico al?m de ser obtido por um m?todo simples, o pigmento ? de baixo custo e reduz o impacto ambiental causado por esse rejeito. Os pigmentos possuem tonalidades marrom claro, vermelha e tons de cinza de acordo com a impregna??o e suas temperaturas de calcina??o, que se tornaram mais escuras em maior temperatura. / Like most of the industries sectors, the ceramic sector also felt the need of developing. In this way, the ceramic industry has been seeking to create more and more pigments for the production of floors and coatings, aiming to meet the demand of ceramics for the decoration of domestic and commercial environments. In addition to that, there is a great interest in developing new materials that are in accordance with the environmental preservation that are also relatively low-cost. Retorted shale (RS) is a waste from the shale industry that may harm health and the environment if improperly stored. The aim of this study is to evaluate the viability of the materials, pure RS and metal-impregnated RS, to obtain pigments that are stable in several ceramic matrices, as well as to try to understand which parameters influence the pigmentation of the enamels. The RS-based pigments were prepared by wet impregnating of the metals and calcined at 700 and 900?C. After that, the materials were characterized by X-ray Fluorescence (XRF), Thermogravimetric analysis (Tg), X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM /EDS), UV-Visible Spectroscopy and Colorimetry. The results confirm the feasibility of using RS as a ceramic pigment obtained by a simple method, low-cost and that reduces the environmental impacts caused by such waste. The pigments are light brown, red and shades of gray, according to the impregnation and calcination temperatures, which get darker at higher temperatures.
3

S?ntese e caracteriza??o de espin?lios a base de Cu, Fe e Cr para pigmentos cer?micos

Costa, Asenete Frutuoso da 10 December 2010 (has links)
Made available in DSpace on 2014-12-17T14:06:56Z (GMT). No. of bitstreams: 1 AseneteFC_DISSERT.pdf: 1219908 bytes, checksum: bebef255f66d82cd8504a8398fd23379 (MD5) Previous issue date: 2010-12-10 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Inorganic pigment comprises a host lattice, which is part of the chromophore component (usually a transition metal cation) and possible components modifiers, which stabilize, add or restate the properties pigments. Among the materials with spinel, ferrites, and the chromite stand out, because they have broad technological importance in the area of materials, applicability, pigments, catalytic hydrogenation, thin film, ceramic tiles, among others. The present work, pigments containing CuFe2O4, CuCr2O4,e CuFeCrO4, were synthesized by a method that makes use of gelatin as organic precursor using their application to ceramic pigments. The pigments were characterized by X-ray diffraction (XRD), Infrared spectroscopy, scanning electron microscopy (SEM) spectroscopy in the UV-visible and Colorimetry. The results confirmed the feasibility of the synthetic route used, with respect to powders synthesized, there is the formation of spinel phase from 500?C, with an increase in crystallinity and the formation of other phases. The pigments were shown to be crystalline and the desired phases were obtained. The copper chromite have hues ranging from green to black according to the calcination temperature, while the copper chromite doped with iron had brownish. The ferrites showed copper color and darker brown to black, which may indicate an interesting factor because of the importance of black pigment / Pigmento inorg?nico ? formado por uma rede hospedeira, na qual se integra o componente crom?foro (normalmente um c?tion de metal de transi??o) e os poss?veis componentes modificadores, que estabilizam, conferem ou reafirmam as propriedades pigmentantes. Dentre os pigmentos, as estruturas tipo espin?lio se destacam por possuir ampla import?ncia tecnol?gica na ?rea de materiais, com aplica??o em pigmentos, cat?lise de hidrogena??o, filmes finos, revestimentos cer?micos, dentre outros. No presente trabalho, pigmentos contendo CuFe2O4, CuCr2O4,e CuFeCrO4 foram sintetizados por uma nova rota qu?mica usando gelatina como precursor org?nico visando sua aplica??o para pigmentos cer?micos. Os pigmentos foram caracterizados por difra??o de raios X (DRX), espectroscopia na regi?o do Infravermelho, Microscopia eletr?nica de varredura (MEV) espectroscopia na regi?o do UV-Vis?vel e Colorimetria. Os resultados confirmaram a viabilidade da rota de s?ntese utilizada; Com rela??o aos p?s-sintetizados, observase a forma??o da fase espin?lio a partir de 500oC, com um aumento da cristalinidade, bem como a forma??o de outras fases. Os pigmentos se mostraram cristalinos e as fases desejadas foram obtidas. As cromitas de cobre possuem tonalidades que v?o do verde ao preto, de acordo com a temperatura de calcina??o, enquanto que as cromitas de cobre dopadas com ferro obtiveram colora??o marrom. As ferritas de cobre apresentaram cores bem mais escuras, do marrom ao preto, o que ? uma caracter?stica interessante devido ? grande import?ncia dos pigmentos pretos na ind?stria cer?mica
4

Otimiza??o do processo de s?ntese do aluminato de cobalto via m?todo de polimeriza??o de complexos (MPC) atrav?s do planejamento fatorial fracionado / Optimization of process of synthesis of cobalt aluminate via complex polymerization method (CPM) through fractional factorial planning.

Gomes, Yara Feliciano 20 December 2012 (has links)
Made available in DSpace on 2014-12-17T14:07:05Z (GMT). No. of bitstreams: 1 YaraFG_DISSERT.pdf: 4146827 bytes, checksum: 3586f66a1b391a184d1b6034e91b85c0 (MD5) Previous issue date: 2012-12-20 / In the ceramics industry are becoming more predominantly inorganic nature pigments. Studies in this area allow you to develop pigments with more advanced properties and qualities to be used in the industrial context. Studies on synthesis and characterization of cobalt aluminate has been widely researched, cobalt aluminate behavior at different temperatures of calcinations, highlighting especially the temperatures of 700, 800 and 900? C that served as a basis in the development of this study, using the method of polymerization of complex (CPM), economic, and this method applied in ceramic pigment synthesis. The procedure was developed from a fractional factorial design 2 (5-2) in order to optimize the process of realization of the cobalt aluminate (CoAl2O4), having as response surfaces the batch analysis data of Uv-vis spectroscopy conducted from the statistic software 7.0, for this were chosen five factors as input variables: citric acid (stoichiometric manner), puff or pyrolysis time (h), temperature (? C), and calcinations (? C/min), at levels determined for this study. By applying statistics in the process of obtaining the CoAl2O4 is possible the study of these factors and which may have greater influence in getting the synthesis. The pigments characterized TG/DSC analyses, and x-ray diffraction (XRD) and scanning electron microscope (SEM/EDS) in order to establish the structural and morphological aspects of pigment CoAl2O4, among the factors studied it were found to statically with increasing calcinations temperature 700?< 800 <900 ?C, the bands of Uv-vis decrease with increasing intensity of absorbance and that with increasing time of puff or pyrolysis (h) there is an increase in bands of Uv-vis proportionally, the generated model set for the conditions proposed in this study because the coefficient of determination can explain about 99.9% of the variance (R?), response surfaces generated were satisfactory, so it s possible applicability in the ceramics industry of pigments / Na ind?stria cer?mica utilizam-se cada vez mais pigmentos de natureza predominantemente inorg?nica. Os estudos nessa ?rea permitem desenvolver pigmentos com qualidades e propriedades mais avan?adas para serem empregados em ?mbito industrial. Estudos de s?ntese e caracteriza??o do aluminato de cobalto t?m sido amplamente pesquisados, o comportamento do aluminato de cobalto em diferentes temperaturas de calcina??es, destacando principalmente as temperaturas de 700, 800 e 900?C utilizando o m?todo de polimeriza??o de complexos (MPC), m?todo este, econ?mico e aplicado em s?ntese de pigmentos cer?micos. O procedimento foi desenvolvido a partir de um planejamento fatorial fracionado 2(5-2) com o objetivo de otimizar o processo de realiza??o do aluminato de cobalto (CoAl2O4), tendo como superf?cies de respostas os dados da an?lise de espectroscopia do Uv-vis realizados a partir do software statistic 7.0, para isso, foram escolhidos cinco fatores como vari?veis de entrada: concentra??es de ?cido c?trico (de maneira estequiom?trica), tempo de puff ou pir?lise (h), temperatura (?C), tempo e taxas de calcina??es(?C/min), em patamares determinados para este estudo. Atrav?s da aplica??o estat?stica no processo de obten??o do CoAl2O4 foi poss?vel estudar entre estes fatores quais possam ter maior influ?ncia na obten??o da s?ntese. Os p?s-precursores foram caracterizados pelas an?lises termogravim?tricas TG/DSC, e os p?s-calcinados (pigmentantes) foram analisados pela difra??o de raios- x (DRX) e microscopia eletr?nica de varredura com energia dispersiva (MEV/EDS) a fim de comprovar os aspectos estruturais e morfol?gicos do CoAl2O4, entre os fatores estudados estaticamente verificou-se que com o aumento da temperatura de calcina??o 700<800<900?C, as bandas do Uv-vis diminuem com o aumento da intensidade da absorb?ncia e que com o aumento do tempo de puff ou pir?lise (h) h? um aumento das bandas do Uv-vis proporcionalmente, o modelo gerado ajustou-se para as condi??es propostas neste estudo, pois o coeficiente de determina??o consegue explicar cerca de 99,9%, da vari?ncia (R?), as superf?cies de respostas geradas foram satisfat?rias, sendo assim sua poss?vel aplicabilidade na ind?stria cer?mica de pigmentos

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