Fabrication of Nanoporous Nickel by Electrochemical Dealloying

The etching of the more active component from a homogeneous alloy is important in corrosion reactions and has been exploited in the synthesis of high surface area nanoporous materials. In this paper we show that nanoporous films can be obtained by selective electrochemical etching of the more noble component in a system where the more active component is passivated. We demonstrate that nanoporous nickel films can be obtained by a two-step process involving electrodeposition of a homogeneous NixCu1-x alloy followed by electrochemical etching of the copper from the alloy. The composition, lattice parameter, saturation magnetization, and Curie temperature of the electrodeposited NixCu1-x alloys can be precisely controlled by varying the deposition conditions. Nanoporous nickel can be formed by electrochemically etching the copper from the alloy. The nanoporous structures are characterized by a three-dimensional network of interconnected pores and exhibit enhanced coercivity and reduced magnetic anisotropy. The morphology of the nanoporous nickel films is dependent on the initial composition of the NixCu1-x alloy.