Efeito da técnica de preparação de pós de heptamolibdato de amônia e nitrato de cobre na densificação e propriedades dos compósitos Mo-Cu
Mo-Cu composite is used in electronic packaging devices, electrical contacts and heat skins. The union of the high electrical and termal conductivity properties of copper with the wear resistance of molybdenum causes strong interest in the electrical and electronics industry. The densification of...
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| Formato: | Dissertação |
| Idioma: | pt_BR |
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Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/handle/123456789/54703 |
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| Resumo: | Mo-Cu composite is used in electronic packaging devices, electrical contacts and
heat skins. The union of the high electrical and termal conductivity properties of
copper with the wear resistance of molybdenum causes strong interest in the
electrical and electronics industry. The densification of these Mo-Cu composites via
sintering is hampered due to the mutual insolubility of Mo and Cu and the low
wettability of Cu to Mo. However, powder metallugy is a viable route to manufacture
this composite. In this work, the influence of mechanical mixing (MM) and high
energy milling (HEM) techniques, as well as the chemical method of coprecipitation
of heptamolybdate (AHM) and copper nitrate (CuN) powders on densification,
microstructure and properties of Mo-Cu composite powder compacts was
investigated. AHM-CuN powders with 10.8 and 13.9 % by mass of CuN were
prepared, respectively, by mechanical (MM and MAE) and chemical coprecipitation
methods. The prepared powders were reduced in 750 °C in tubular furnace under
H2 atmosphere and a flow of 316 mL/min. The composite Mo-Cu powders with 20
and 25 % by mass of Cu obtained were compacted at 250 MPa and the green
compacts produced were sintered at 1.150 °C for 1 h under na atmosphere of H2.
The sintered bodies of Mo-Cu powders prepared by coprecipitation and HEM
reached a relative density of 96 ± 2.7%, while those prepared by MM reached only
75 %. Said sintered compacts achieved, respectively, a microhardness of 190.7 ±
15.4, 293.3 ± 13.4 and 183.2 ± 18.6 HV, as well as na electrical conductivity of
respectively 34, 22 and 15 IACS. The greater homogenization and smaller grain
size resulting from the preparation of Mo-Cu powders by coprecipitation and HEM
are responsible for obtaining the highest values of density, microhardness and
electrical conductivity of the sintered Mo-Cu compacts. |
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