Modelling the electrodeposition of nickel on polyurethane foam

Abstract

The electrodeposition method is among the various methods to produce metal foams by coating open-cell polymeric foams with a metallic layer. This process is governed by strong mechanical and electrical interactions which arise due to different factors such as presence of ions in the electrolyte, applied external current, charged solid surface and ionic concentration gradient. Hence, the related physical effects result in a nonlinear coupled process at the macroscale, which introduces a complex challenge for modelling and computational treatment. This work proposes a model to describe the electrocoating of polyurethane foams with nickel ions at macroscale, in an isothermal process and under the simplifying assumptions such as rigidity of the foam and incompressibility of the electrolyte. To do so, the multi-phase flow through the porous medium has to be modelled on a macroscopic scale. The governing equations describing the coating process are developed from the fundamental balance equations of mixture theory. By reasonable physical assumptions, different processes contributing to ionic transport, i.e. diffusion, convection and migration, are considered, and finally, the influence of different parameters in each transport mechanism is investigated. First 1D simulations show that the presented model is able to describe the experimentally observed effects, at least in a qualitative way.