Navegando por Assunto "Electrodeposition"

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Acesso aberto (Open Access)
Eletrodeposição e caracterização de revestimento de cobre/nanotubos de carbono dopados com iodo em fios de alumínio liga 1350
(Universidade Federal do Pará, 2023-09-19) RODRIGUES, Fabrício Augusto dos Santos; LEITE, Marcos Allan Reis; http://lattes.cnpq.br/8252507933374637
Nanocomposites based on copper and carbon nanotubes (Cu/NTC) in metallic matrix have been providing improvements in the electrical and thermal properties of materials, presenting great potential for application in areas such as the electrical sector. Great challenges are encountered in the transmission and distribution of electrical energy, such as technical losses, mainly due to the Joule effect, resulting in low efficiency of conventional aluminum (Al) conductors. In this sense, new nanostructured conductors were developed based on functionalized copper/carbon nanotubes and doped with iodine (Cu/NTC-f), as a coating for Al 1350 aluminum wires, using the electrophoretic deposition process in copper sulfate solution, under electrical currents of 1.2 A, 1.5 A and 1.8 A, were investigated for their electrical and mechanical properties. Al@Cu/NTC-f conductors were characterized by scanning electron microscopy; X-ray diffraction; Raman spectroscopy; tensile test, in addition to electrical measurements, at room temperature and under heating, via Kelvin bridge. The results show an increase of approximately 18% of the IACS with good stability under heating compared to the commercial aluminum conductor Al 1350, due to the intrinsic properties of the NTCs, functionalization, good dispersion and the doping effect of iodine, confirmed by Raman spectroscopy with redshifts in the Gint and Gext subbands. The characteristic morphology of the thin films of Cu/NTC-f, presented pyramidal structures, agglomerates, copper structures involved the NTC, as well as NTC homogeneously electrodeposited in the aluminum substrate with good crystallinity, cultivated in the directions (311) and Cu (220), Cu (200), favoring the formation of thin films with good crystallinity. This method of electrodeposition of Cu/NTC-f on the surface of metallic wires shows promise for the production of nanostructured metallic conductors of high ampacity, thermal stability, low density and high performance, applied in electric power transmission lines.
Acesso aberto (Open Access)
Obtenção de filmes finos de ligas de alta entropia à base de CoFeNi por eletrodeposição em meio aquoso
(Universidade Federal do Pará, 2025-04-25) FREITAS, Gregório Felipe do Nascimento; NOCE, Rodrigo Della; http://lattes.cnpq.br/3734170057844016
High-entropy alloys, also called multicomponent alloys, are alloys that have five or more elements whose composition is formed between 5% and 35% in terms of atomic composition of the elements. These alloys have gained prominence recently because they present very distinct and attractive properties in relation to conventional alloys composed of a single major element. In this context, the alloys have been produced by different physical and chemical methods. The present work addresses the subject of obtaining thin films of high-entropy alloys based on CoFeNi by the electrodeposition technique in aqueous medium, with additions of elements such as Mo, Mn, Sn and W. A simple and low-cost technique in relation to other methods proposed in the literature. By using the direct current (galvanostatic) method at room temperature and by varying the current density to obtain thin films in a range of 5 to 100 mA/cm2, the high entropy alloy CoFeNiMoW and the possibility of obtaining the CoFeNiMnSn alloy on a brass substrate (CuZn) are demonstrated. The electrodeposited films are characterized by Energy Dispersive Spectroscopy (EDS), Scanning Electron Microscopy (SEM), X-ray Diffractometry (XRD) and Mossbauer Spectroscopy techniques. EDS analyses reveal that the composition of the alloys is strongly influenced by the applied current density. In the high entropy alloy with five elements CoFeNiMoW formed from applied current density of 50 mA cm-2, the atomic proportion obtained is Co 30%, Fe 21%, Ni 19%, Mo 25%, W 5%. For the CoFeNiMnSn alloy, its composition formed by means of a current density equal to 50 mA cm-2 is Co 26.2%, Fe 33.8%, Ni 5.5%, Mn 1.8%, Sn 32.6%, thus evidencing the formation of alloys with five elements by the proposed method.