Buffered electropolishing parameters on niobium sheet

In this paper, studies on applying a new electrolyte to treat the surfaces of Nb sheets, which was called buffered electropolishing (BEP), were reported. Through studies of the BEP I-V characteristic and optimization of main parameters such as acid agitation, temperature, etc., much faster Nb polishing rate and smoother surface finish were achieved in comparison with those obtained from the conventional electropolishing (EP). The average polishing rate could reach around 2.5 μm/min. It was over 7 times faster than that of the traditional EP. Meanwhile, the average surface mean square root roughness was around 50 nm over an area of (200×200) μm^{2}. This study shows BEP has a great potential to replace the traditional EP process and becomes a new generation of technology for treating Nb superconducting radio frequency cavities