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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.

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