| The fabrication of micro and nanostructures is a vital process for a wide range of applications including microreactors, integrated circuits, and metal micromachining. A versatile electrochemical method suitable for micro and nanofabrication on a multitude of conducting and semi-conducting substrates is electrochemical machining with ultrashort voltage pulses or ultrashort pulse electrochemical machining. These pulses, typically 200 ns or less, are applied to a micro or nanoscale tool electrode that electrochemically machines its imprint into a substrate electrode. The ultrashort pulses are utilized to exploit the dependence of the time constant for charging the substrate electrode/electrolyte region on the distance between the tool electrode and the substrate electrode.;The work in this dissertation focused on expanding the capabilities of electrochemical machining with ultrashort voltage pulses to new materials and new applications. This work can be divided into three parts. In the first, ultrashort pulse electrochemical machining was used to fabricate submicron features on p-Si substrates approaching 100 nm. In the second, masters were fabricated into Ni Substrates and utilized in a novel microcontact printing process for cellular patterning. Finally, in the third, electrochemical machining with ultrashort voltage pulses was used to create microstructures on two industrially relevant alloys: the corrosion resistant Hastelloy B-2 (Ni-Mo) and the shape memory alloy NiTi. |
