Towards selective compositionally graded coatings by electrochemical jet processing

In this study, we describe a new methodology to create complex coatings with functionally graded compositions, using electrochemical jet processing (EJP). Cu/Zn alloy coatings were electrodeposited, in a layer-by-layer manner, onto steel substrates through resin masks created with a desktop 3D printer. By adapting the electrolyte composition through the jet by drawing from multiple reservoirs, the ratio of cations (Cu2+:Zn2+) in the electrolyte supplied directly to the substrate surface at any point in the processing cycle can be manipulated. This allows for control over electrodeposit composition ratios through a given coating, while the mask allows for microfabrication at higher aspect ratios than achievable by electrochemical jet processing alone. After processing, masks were removed from the substrates and samples were subsequently characterised to verify changes in composition and deposition properties.