The morphology and the microstructure of alloys grown by co-electrodeposition generally result from kinetics and depart from equilibrium. On the atomic scale key parameters include binding energies (e.g. adatom – surface, adatom – adatom etc.) and also on adatom mobility.

 In this presentation we will examine the impact of above parameters on Ni alloy monolayers electrodeposition. An unreconstructed Au_Pd(111) substrate is used to co-deposit Ni and Ag, Au [1] and Pd [2]. These elements were chosen because they present different bulk mixing enthalpies with Ni, from phase separation (Ag) to perfect mixing (Pd). These three elements present also quite different surface mobility. Complementary experiments in which the two metals are sequentially deposited [3] [4] as well as dealloying experiments (selective dissolution of Ni) [5] will be presented in support of discussion. References :

[1] F. Lecadre et al. AuNi alloy monolayer films electrodeposited on Au(111): An in situ STM study, Surf. Sci. 607, 25 (2013).

[2] A. Damian et al. Electrodeposition of NiPd monolayer on Au(111): An in situ scanning tunneling microscopy study, Electrochim. Acta 112, 824 (2013).

[3] A. Damian et al. Selective Growth and Dissolution of Ni on a PdAu Bimetallic Surface by In Situ STM: Determining the Relative Adsorbate-Substrate Interaction Energy, Phys. Rev. Lett. 102, 196101 (2009).

[4] F. Lecadre et al. Electrodeposition of Ag, Pd and Au on Ni monolayer islands on (1 × 1)-Au(111) by in-situ scanning tunneling microscopy, Electrochim. Acta 197, 241 (2016).

[5] A. Damian et al. Electrochemical de-alloying in two dimensions: role of the local atomic environment, Nanoscale 8, 13985 (2016).