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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

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

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