(Invited) Short Introduction of Brenner's Paradigm on the Steady State Diffusion Layer Model of Alloy Electrodeposition Composition Control, and Its Possible Extensions

摘要

Understanding the composition control of alloy electrodeposition is the prerequisite of pursuing fundamental understandings of phase and morphology evolution in the deposit. It is well known that a constant electrolyte concentration boundary, called diffusion layer, will form when the system is under forced convection or natural convection. Given enough time, the thickness of diffusion layer, which in the beginning follows the Cottrell equation, will reach a steady state value, and thus a steady state deposition flux rate and deposition current could be estimated using the ionic diffusivity and diffusion layer length. For alloy electrodeposition, using the steady state deposition flux rate, ideally, the composition of the deposit could be predicted by the concentration ratio in the electrolyte and the mass-transfer coefficient ratio of the depositing ions.