(Invited) Patterned Printing of Ceramics By Electrodeposition, and Applications in Micro-Robotics

Developing cost-effective capabilities to fabricate materials into desired shapes and sizes has always been a prime focus of materials research. Selective-laser sintering, which is based on sintering of tiny particles, is currently limited to polymers and metals, and is generally not directly applicable to ceramic powders because of their high melting temperatures. Electrodeposition has the advantages of low costs, availability at room temperature and easy scalability. In this paper, an efficient technique for writing 2D oxide patterns on conductive substrates is demonstrated. In this method, a minimum quantity of liquid electrolyte is delivered through an extrusion nozzle and manipulated into the desired shape on the substrate, meanwhile being electrodeposited into the product by an applied voltage across the nozzle and substrate. Using this method, patterns of primarily Cu2O were successfully fabricated on stainless steel substrates. This is intriguing because, according to the Pourbaix diagram, the equilibrium deposited product at the low voltage used should be metallic Cu. A key factor that allows the product to be primarily oxide Cu2O is the non-equilibrium condition involved in the process due to the short deposition time; hence the nature of the product is shown to be tunable by printing conditions. A second material printed using this method was nickel hydroxide/oxyhydroxide which exhibits an interesting electrochemical actuation effect in alkaline media. Applications in printing micro-robots involving this material will also be discussed.