Electrochemical micromachining microstructure lattice on magnesium alloy surface

Micromachining of magnesium alloy by confined etchant layer technique (CELT) was investigated. The variation of hydrogen ion concentration on the electrode surface during the electrochemical process was explored for some thermodynamically available "etchant-scavenger" systems, and their corrosion rate to magnesium alloy was measured. An effective electrochemistry "etching-scavenging" system was selected. Using NaNO2 as precursor for electrochemically generating etchant HNO3, NaOH as scavenger, and small amount of Na2SiO3 as inhibitor, 3-D microstructure lattice on a mold was replicated onto the magnesium alloy surface. The microstructures processed were approximately the negative copy of the ones on the mold. Sub-micrometer scale resolution was reached. The result suggested that CELT could be applied to machine the 3-D microstructure on magnesium alloy surface, which had potential to be used for the fabrication of micro electromechanical systems (MEMS).