| Summary: | 碩士 === 長庚大學 === 機械工程學系 === 100 === The electropolishing behavior of 73-brass in phosphoric acid aqueous solutions was discussed in this study. The results showed that the anodic polarization curves of the 73-brass in phosphoric acid could be divided into active, limiting current and oxygen evolution region, and an obvious peak could be found between active and limiting current region. In order to explore the anodic dissociation behavior of 73-brass which was electropolished in different potential regions and find the best electropolishing parameters.
In this experiment, 73-brass was electropolished in the peak, front-end, middle and rear of the limiting current region respectively by means of rotating cylinder electrode and rotating disk electrode. The surface morphology electropolished in middle of limiting current region could be found excellent effect by means of optical microscopy and scanning electron microscopy. Moreover, atomic force microscopy analysis showed that the minimum surface roughness value of 0.45 nm (Ra) could be obtained when electropolishing in 70 vol.% phosphoric acid with rotation speed of 500 rpm in middle of the limiting current region.
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