Electrochemical processing of porosity gradients for the production of functionally graded materials

The present paper lays the theoretical foundations of a new production proc ess for functionally graded materials (FGMs). The process is based on the e volution of porosity gradients in porous electrodes which undergo electroch emical dissolution or deposition. The electrodes with graded porosity serve as preforms for the production of graded composites by infiltration proces sing. A one-dimensional macroscopic model of the porous electrode has been used for the prediction of the porosity gradients. A numerical approach all ows utilization of experimentally determined current-potential curves for n onporous electrodes, with the incorporation of changes of the pore structur e during the course of the electrode reaction, to predict the porosity grad ients. For porous copper cathodes and anodes the results of this model are compared with experimentally observed polarization behavior and porosity di stributions for different current densities and electrolyte conductivities.