Electrochemical etching of a shape memory alloy using new electrolyte solutions

In this paper we present the electrochemical etching characteristics of a shape memory alloy (SMA) using new electrolytes of inorganic salt in alcohol, in comparison with conventional H2SO4-methanol solution. It has become apparent that pattern etching of SMA sheets can be carried out in electrolyte solutions using LiCl and NH4Cl. Especially, in the case of 1 mol l(-1) LiCl-ethanol, good etching properties such as a controllable low etch rate of about 3.5 mum min(-1), high etch factor (etching depth/side etching width) of 1.5, uniform etching depth and smooth etched surface can be obtained. Throughout etching can be carried out by using a back-side dummy metal of Ni or Cu. This etching technique has been applied to the micromachining of SMA sheet for fabrication of microactuators.