Investigation of the Structural Coating Homogeneity in Open-Porous Nickel/Polyurethane Hybrid Foams Produced by Flow-Controlled Electrodeposition

Abstract

In today's world, the saving of raw materials together with the reduction of emissions necessitates the development of new, customized and application-oriented materials which fulfill various requirements at the same time. Metal foams achieve a high strength combined with low weight. The present work deals with a flow-controlled production technique for hybrid foams to deposit a nanocrystalline nickel (Ni) layer on pre-treated, open-porous polyurethane (PU) foams. The analysis of the resulting coating thickness distributions with gravimetric and microscopic methods shows the qualitative and quantitative influences on the local deposition by varying the process parameters. For the first time, the coating thickness distribution of Ni/PU hybrid foams is investigated regarding the analysis of a global and local homogeneity. The comparison of experimental data with simulated flow velocity profiles leads to an estimation of the correlation between flow velocity, anode distance, and coating thickness distribution, which represents the mass transport. The correlations show, that the coating process is strongly controlled by the electrolyte's flow velocity as well as the distribution of the electric field.