Electrochemical sharpening of metal wires can be achieved by rapid etching in the electropolishing regime. The electropolishing of nickel in H2SO4 glycerine/water solutions was found to be associated with the formation of a salt film at the surface. The shape of the tips was found to be dependent on the etching conditions : low aspect ratio tips were obtained in solutions with high resistivity, whereas high aspect ratio tips were produced in solutions with lower resistivity.