Wire electropolishing of microgroove structures on a cobalt-based alloy

Abstract

The surface quality of microstructures greatly affects their performance. Electropolishing has many advantages as a technique for eliminating surface defects of microstructures and components. This paper presents a new electropolishing method to improve the surface quality of microgrooves. A wire with a diameter in the micrometer range is employed as the cathode. The whole of the microgroove is polished by moving this wire electrode along the outline of the microgroove. The anodic dissolution behaviors of a cobalt-based alloy in phosphoric acid solutions with various concentrations are investigated using polarization curves. The effects of the wire electropolishing parameters, namely, the wire electrode diameter, feed rate, polishing gap, applied voltage, pulse period, and duty cycle are also studied both theoretically and experimentally. Using optimized values of these parameters, the surface roughness of the microgroove is reduced from Ra = 0.3 to 0.036 μm. A mirror-like surface is obtained after polishing.