The electropolishing of a B-doped diamond (BDD) film deposited by CVD was studied in HOAc-H2SO4 media. The electropolished surface was characterized by SEM, XPS, and electrochem. measurements. In 1 M H2SO4 no polishing of the surface occurred even after prolonged time; on the contrary, in electrolyte contg. 3 M HOAc in 1 M H2SO4 the morphol. changed rapidly. The surface became smoother and the roughness decreased as the typical results of a polishing process. All the nondiamond impurities were also removed by the electropolishing treatment in HOAc media. [on SciFinder (R)]