화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.158, No.3, D149-D157, 2011
Underpotential Codeposition of Fe-Pt Alloys from an Alkaline Complexing Electrolyte: Electrochemical Studies
The availability of electrochemical growth processes for Fe-Pt alloys may facilitate their integration within microfabrication manufacturing lines and enable novel functionalities in microsystems. In this paper, the electrodeposition of Fe-Pt from slightly alkaline solutions containing citrate, glycine, and amino-nitrite complexes is studied by means of electrochemical quartz crystal microbalance (EQCM) and analytical/structural investigations. Pt is reduced from its amino-nitrite complex while Fe is reduced from Fe3+ citrate/glycinate complexes through a two-step process. At variance with similar films grown from acidic solutions, the electrolyte is stable over months and the resulting films are smooth, dense, and homogeneous. Most importantly, oxygen incorporation is limited to 1-6 atom %. Significant carbon incorporation from decomposition of the complexants and kinetic trapping during growth is observed. The dependence of alloy composition on applied potential can be explained by assuming underpotential codeposition of iron from a Fe2+ intermediate; the experimentally determined alloy composition dependence on applied potential was in agreement with an estimate of the redox potential for the Fe2+/Fe reaction obtained by EQCM and the reported enthalpy of mixing of the bulk Fe-Pt phase at high temperature. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3530786] All rights reserved.