Gomes, Uilame UmbelinoOliveira, Gerlânea Silva de2024-02-152024-02-152023-12-13OLIVEIRA, Gerlânea Silva de. Influência da adição de níquel nas propriedades microestruturais e físico-mecânicas do compósito W-Cu-Ni. Orientador: Dr. Uílame Umbelino Gomes. 2023. 92f. Tese (Doutorado em Ciência e Engenharia de Materiais) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2023.https://repositorio.ufrn.br/handle/123456789/57597This study investigates the influence of Nickel addition on the microstructure and mechanical properties of the W-Cu composite. Tungsten and its composites, such as the tungsten-copper (W-Cu) and tungsten-copper-nickel (W-Cu-Ni) systems, have attracted increasing interest due to their excellent mechanical, physical, and chemical properties. These materials are particularly relevant for applications in electroelectronics, presenting no toxicity or environmental risks. Given this, the present work studied the influence of nickel addition, in different percentages, on the microstructural and physico-mechanical properties of the W-CuNi composite, obtained by different routes, high-energy milling and reduction, and sintered via Pulsed Plasma Sintering – SPS and in a Resistive Tubular furnace. The effects of processing stage variables on the properties of the W-Cu-Ni composites were also evaluated. To obtain the powders, the following initial compositions were mixed: W70%wt.Cu30%wt.Ni0%wt., W70%wt.Cu28%wt.Ni2%wt., and W70%wt.Cu25%wt.Ni5%wt., which were subsequently milled in a high-energy planetary mill for 10 hours. And, for the reduction, APT and copper and nickel nitrates were mixed under magnetic stirring in a wet medium, with ethyl alcohol, for 30 minutes at a temperature of 60°C. Sintering was carried out through SPS, at temperatures of 900°C and 1000°C, and in a resistive furnace, with argon and hydrogen gas flow, at temperatures of 1100°C and 1200°C. The starting powders (W, Cu, and Ni) and those milled, in the proportions previously mentioned, were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). After sintering, the samples were characterized by SEM, EDS, density measurements, and microhardness. The results of the scanning electron microscopy and EDS revealed that highenergy milling for 10 hours and the reduction of the precursors were sufficient to obtain the composite with good homogeneity and free of impurities. The XRD diffractograms showed the peaks of the composite's characteristic phases. The sintered compacts showed densities ranging from 64.8% to 99.98%, and microhardness from 156.4 HV to 418.46 HV. The CM-2 sample (W70%wt.Cu28%wt.Ni2%wt.) sintered at 1000 °C via SPS showed the highest density value (86.27%) and the highest microhardness value (371.4 HV), and the CR-2 sample (W70%wt.Cu28%wt.Ni2%wt.) sintered at 1200 °C in a resistive furnace showed the highest density value (99.98%) and the highest microhardness value (418.46HV), consequently lower porosity, also revealed by the micrography that shows uniformly distributed particles and a homogeneous microstructure in terms of shape and grain size. Thus, the addition of small amounts of nickel and the increase in sintering temperature positively influenced the mechanical properties of the composite under study.Acesso AbertoReação de reduçãoMoagem de alta energiaSinterizaçãoSistemas W-Cu-NidoctoralThesisCNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA