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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

Obten??o de uma porcelana diel?trica a partir de mat?rias-primas do Rio Grande do Norte

Silva, Elialdo Chib?rio da 26 March 2010 (has links)
Made available in DSpace on 2014-12-17T14:07:04Z (GMT). No. of bitstreams: 1 ElialdoCS_TESE.pdf: 4625434 bytes, checksum: bec8d03e9004e11648c49c45f84ffe0f (MD5) Previous issue date: 2010-03-26 / Universidade Federal do Rio Grande do Norte / The dielectric porcelain is usually obtained by mixing various raw materials proportions and is used in the production of electronic equipment for various applications, from capacitors of high and low Power to insulators for low, medium, high and extra high voltage, which are used in distribution lines and transmission of electricity.This work was directed to the s tudy of technological properties of technic porcelain, made from raw materials extracted from pegmatites found in the regions of Serid? and the Alto Oeste of Rio Grande do Norte, which are made of kaolin, quartz and feldspar, abundant and high quality in these regions. The technic ceramics were obtained by mixing in appropriate levels, kaolin, feldspar, quartz and clay, the last item from a pottery in the city of Sao Gon?alo do Amarante, Rio Grande do Norte. During the development the following characterizations correlated to raw materials were made: laser particle sizing, x-ray diffraction, DTA and TG. The compositions studied were formed by uniaxial pressing at a pressure of 50 MPa and sintered at temperatures ranging from 1150 to 1350?C and levels (times) of sintering between 30, 60, 90 and 120 minutes. The characterization of the samples were taken from the analysis of weight loss, linear shrinkage, porosity, stoneware curve, bulk density, flexural strength of three points, SEM and X-ray diffraction, TMA, Dielectric and cross Resistivity. The studied materials can be employed in producing the objects used in electrical engineering such as: insulators for low, medium and high-voltage electrical systems, command devices, bushing insulation for transformers, power capacitors, spark plugs, receptacles for fluorescent and incandescent light bulbs and others / A porcelana diel?trica ? normalmente obtida atrav?s da mistura de diferentes mat?rias-primas, em propor??es adequadas, sendo utilizada na produ??o de equipamentos eletroeletr?nicos de diversas aplica??es, desde capacitores de alta e baixa pot?ncia, a isoladores para baixa, m?dia, alta e extra alta tens?o, que s?o utilizados em linhas de distribui??o e transmiss?o de energia el?trica. Neste trabalho, s?o estudadas as propriedades tecnol?gicas de uma porcelana diel?trica, formulada a partir de mat?rias-primas obtidas de pegmatitos encontrados nas regi?es do Serid? e do Alto Oeste do Rio Grande do Norte, sendo estas constitu?das de caulim, quartzo e feldspato, abundantes e de alta qualidade nestas regi?es, e de uma argila proveniente de uma cer?mica situada no munic?pio de S?o Gon?alo do Amarante, tamb?m no Estado do Rio Grande do Norte. As mat?rias-primas foram caracterizadas atrav?s de: granulometria a laser, difra??o de raios X, an?lise t?rmica diferencial e an?lise termogravim?trica. As amostras foram conformadas por prensagem uniaxial a uma press?o de 50 MPa, e sinterizadas ?s temperaturas de 1150, 1200, 1250, 1300 e 1350 ?C, com patamares de sinteriza??o de 30, 60, 90 e 120 minutos. Os ensaios tecnol?gicos realizados foram: an?lise da perda de massa, retra??o linear, porosidade, curva de gressifica??o, microscopia eletr?nica de varredura, difra??o de raios X, dilatometria, rigidez diel?trica, resistividade transversal e permissividade diel?trica. Os melhores valores de propriedades foram obtidos na temperatura de 1250 ?C, para as composi??es estudadas, n?o sofrendo varia??es significativas em seu comportamento com o tempo de sinteriza??o. Os materiais estudados podem ser empregados na obten??o de objetos usados em eletrot?cnica como por exemplo: isoladores de baixa, m?dia e alta-tens?o para redes el?tricas, dispositivos de comando, bucha de isolamento de transformador, capacitores de pot?ncia, vela de igni??o, recept?culos de l?mpadas incandescentes e fluorescentes e outros

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