Eur. Phys. J. B 22, 485-495 (2001)
https://doi.org/10.1007/s100510170099

Growth velocity and the topography of Ni-Zn binary alloy electrodeposits

Unité de Thermique et d'Analyse Physique - LMET, UPRES EA n° 2061, UFR Sciences Exactes, Université de Reims, BP 138, 21 rue Clément Ader, 51685 Reims Cedex 02, France

Corresponding author: ^a jean.ebothe@univ-reims.fr

Received: 16 August 2000
Revised: 20 June 2001
Published online: 15 August 2001

Abstract

We show that the electrodeposition of Ni-Zn alloys at the lowest growth velocities, m/s, exclusively proceeds from an abnormal co-deposition phenomenon. The growth process in this v region greatly depends on the initial [ Co²⁺] concentration of the film deposition bath. A theoretical approach of this process including the role of the saturation surface roughness of the alloy, , leads to an estimation of the transport properties of the ad-atoms involved during the deposit formation. Their surface diffusion coefficient varying between and cm^-2/s exhibits a minimal value, cm^-2/s located between v = 0.17 and m/s. The spatial scaling analysis of the local roughness, σ, examined according to the power-law reveals that the resulting roughness exponents concurs with the Kardar-Parisi-Zhang dynamics including the restricted surface diffusion. Two main v regions leads to different fractal textural features of the alloy film surface. Below 0.10 μm/s, the roughness exponent obtained is , depicting a limited ad-atom mobility. Over m/s, this exponent stabilises at , indicating an increase of the surface diffusion.