Engenharia Química

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http://repositorio.ufes.br/handle/10/17472
Programa de Pós-Graduação em Engenharia Química

Centro: CCAE
Telefone: (28) 3552 8719
URL do programa: http://www.engenhariaquimica.alegre.ufes.br/pos-graduacao/PPEQ

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Navegando Engenharia Química por Assunto "altas temperaturas"

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    Produção e caracterização de ligas de Nb-Ni-Cu-WC via Sinterização por Plasma Pulsado
    (Universidade Federal do Espírito Santo, 2020-12-17) Ribeiro, Yara Daniel; Azevedo, Márcia Giardinieri de; http://lattes.cnpq.br/1062041229035074; Oliveira, Michel Picanço; https://orcid.org/0000-0001-9241-0194; http://lattes.cnpq.br/6383844066460475; https://orcid.org/0000-0002-3603-3264; http://lattes.cnpq.br/6619922564101297; Guimaraes, Damaris; https://orcid.org/0000000249323252; http://lattes.cnpq.br/6576377621734943; Peçanha Junior, Luiz Antônio Fonseca ; https://orcid.org/0000-0002-0944-6370; http://lattes.cnpq.br/9570896373469295
    In this study three alloys composed by Nb-xNi-2WC-2Cu (x=5, 10 and 15% in weight) were produced via Spark Plasma Sintering (SPS), with the object of manufacturing alloys with high mechanical and oxidation resistance when exposed to high temperatures. The high purity starting powders were mixed by a high energy ball mill and consolidated via spark plasma sintering at the temperatures 1000, 1100 and 1200°C, at a constant pressure of 35 Mpa. All samples were characterized in relation to the formed phases, microstructure, densification, hardness and oxidation resistance. The X-RD analisys allowed to observe the formation of the phases Nb, NbO, NbC, Nb2C, W, WC, NbW, δ-Ni3Nb and γ”-Ni3Nb. In the SEM-EDS, the elevation of the sintering temperature increased the homogeneity of the distribution of the elements and decreased the porosity of the specimens. The samples densification varied between 77,4% and 96,97%. The curves registered by the SPS corroborated with the results of densification, showing a greater reduction in volume for the alloys prepared at 1100 and 1200°C. The sintered alloys showed high hardness when compared with other similar composition alloys, reaching up to 1205,1 HV. Both in the hardness test and in the densification test was possible to observe again that the increase in the sintering temperature contributed to improve the final properties of the samples. All of them showed oxidation behavior according to the parabolic rate law, in other words, oxidation was controlled by diffusion. The parabolic rate constant showed a better result in the sample M1 sintered at 1200°C, whereas the worst rate achieved was in the sample M3 prepared at 1000°C, being, respectively, 1.84070 and 4.77481 x 10-7 g 2 / cm4 .s. With the obtained results it was possible to conclude that the applied methodology was efficient for the production of the proposed alloys, that the increase in the sintering temperature has a positive influence on the final material, and finally, that the combination of the M1 composition and the sintering temperature of 1200 ° C resulted in the alloy with superior properties, being then the best studied parameters
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    PRODUÇÃO E CARACTERIZAÇÃO DE LIGAS DE Nb-W-(Ti6Al4V)-Cu VIA SINTERIZAÇÃO POR PLASMA PULSADO
    (Universidade Federal do Espírito Santo, 2020-12-18) Soares, Alexandre Candido; Oliveira, Michel Picanco; https://orcid.org/0000000192410194; http://lattes.cnpq.br/6383844066460475; https://orcid.org/; http://lattes.cnpq.br/; Guimaraes, Damaris; https://orcid.org/0000000249323252; http://lattes.cnpq.br/6576377621734943; Azevedo, Marcia Giardinieri de; https://orcid.org/; http://lattes.cnpq.br/; Oliveira, Barbara Ferreira de; https://orcid.org/; http://lattes.cnpq.br/
    The use of niobium (Nb) based alloys has been gaining prominence due to the combination of its high melting point and low densities, demonstrating great potential for applications in high temperature environments. Thus, this study aimed to develop and cha