Grain boundary segregation and interdiffusion effects in nickel-copper alloys : an effective means to improve the thermal stability of nanocrystalline nickel
Pellicer Vilà, Eva Maria (Universitat Autònoma de Barcelona. Departament de Física)
Varea Espelt, Aïda (Universitat Autònoma de Barcelona. Departament de Física)
Sivaraman, K. M. (Institute of Robotics and Intelligent Systems)
Pané i Vidal, Salvador (Institute of Robotics and Intelligent Systems)
Suriñach, Santiago (Universitat Autònoma de Barcelona. Departament de Física)
Baró, M. D. (Universitat Autònoma de Barcelona. Departament de Física)
Nogués, Josep (Institut Català de Nanociència i Nanotecnologia)
Nelson, Bradley J. (Institute of Robotics and Intelligent Systems)
Sort Viñas, Jordi (Universitat Autònoma de Barcelona. Departament de Física)

Date:	2011
Abstract:	Nanocrystalline (nc) Ni films show pronounced grain growth and suffer from concomitant deterioration of their mechanical and magnetic properties after annealing at relatively low temperatures (T(ANN) ≥ 475 K). This constitutes a drawback for their applicability as coatings or in components of miniaturized devices. This work reveals that the thermal stability of nc Ni is significantly improved by controllably alloying Ni with Cu, by means of electrodeposition, to form a Ni(1-x)Cu(x) solid solution. To tune the composition of such nc alloys, Ni(1-x)Cu(x) films are deposited galvanostatically using an electrolytic bath containing Ni and Cu sulfate salts as electroactive species, saccharine as grain-refining agent, and applying current densities ranging from -10 to -40 mA cm(-2). The enhanced thermal stability is ascribed to segregation of a Cu-rich phase at the Ni(1-x)Cu(x) grain boundaries, which acts as a shielding layer against grain growth. As a result, high values of hardness (in excess of 6 GPa) remain in nc Ni(1-x)Cu(x) for x ≥ 0. 3, even after annealing at T(ANN) ≥ 575 K. From a magnetic point of view, Ni(1-x)Cu(x) films possess lower coercivity values than pure nc Ni films, both in the as-prepared and annealed states, thus offering potential advantages for certain soft magnetic applications.
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Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Pel·lícules fines ; Nanoestructures ; Coure -- Aliatges ; Níquel - Aliatges ; Electrodeposició de metalls ; Corrossió i anticorrosius
Published in:	ACS applied materials & interfaces, Vol. 3, Núm. 7 (July 2011) , p. 2265-2274, ISSN 1944-8252

DOI: 10.1021/am2004587

10 p, 3.9 MB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Articles > Research articles
Articles > Published articles