Porter, R.D. Furuta, F. Hall, D.L. Liepe, M. Maniscalco, J.T. JACoW Geneva, Switzerland 978-3-95450-182-3 10.18429/JACoW-IPAC2017-MOPVA124 English 1145-1148 MOPVA124 Contribution to a conference proceedings 2017 2017-05 http://dx.doi.org/10.18429/JACoW-IPAC2017-MOPVA124 http://jacow.org/ipac2017/papers/mopva124.pdf Current Niobium-3 Tin (Nb3Sn) superconducting radio-frequency (SRF) accelerator cavities have rougher surfaces than conventional electropolished Niobium accelerator cavities. The surface roughness can cause enhancement of the surface magnetic field, pushing it beyond the critical field. If this occurs over a large enough area it can cause the cavity to quench. The surface roughness may cause other effects that negatively impact cavity quality factor (Q) performance. Reducing surface roughness of Nb3Sn cavities may be necessary to achieve higher gradient with high Q. Current chemical treatments for reducing the surface roughness of Niobium are challenging for Nb3Sn: the Nb3Sn layer is only ~2 um thick while it is difficult to remove less than 1 mu uniformly with most chemical treatments. This paper presents measurements of the surface roughness before and after Buffered Chemical Polish, Electropolishing and oxipolishing.