Electrolyte solution and electropolishing methods

A method of micropolishing a surface of a non-ferrous metal workpiece, comprising:

• immersing a surface of a non-ferrous metal workpiece in a bath of an aqueous electrolyte solution including a concentration of citric acid greater than or equal to about 600 g/L and a concentration of ammonium bifluoride less than or equal to about 20 g/L, and having no more than about 3.35 g/L of a strong acid;
• controlling the temperature of the bath to be greater than or equal to about 71° C.;
• connecting the workpiece to the anode of a DC power supply and immersing a cathode of the DC power supply in the bath;
• applying a current across the bath of greater than or equal to about 538 amperes per square meter and less than or equal to about 255,000 amperes per square meter;
• continuing the immersion of the surface in the bath until the finish of the surface is smoother than prior to immersion in the bath;
• and
• removing the surface from the bath prior to causing a substantial change in the size or geometric shape of the workpiece.

A method of micropolishing a surface of a non-ferrous metal workpiece, comprising:

• immersing a surface of a non-ferrous metal workpiece in a bath of an aqueous electrolyte solution including a concentration of citric acid less than or equal to about 780 g/L and a concentration of ammonium bifluoride less than or equal to about 60 g/L, and having no more than about 3.35 g/L of a strong acid;
• controlling the temperature of the bath to be less than or equal to about 85° C.;
• connecting the workpiece to the anode of a DC power supply and immersing a cathode of the DC power supply in the bath;
• applying a current across the bath of greater than or equal to about 538 amperes per square meter and less than or equal to about 255,000 amperes per square meter;
• continuing the immersion of the surface in the bath until the finish of the surface is smoother than prior to immersion in the bath;
• and
• removing the surface from the bath prior to causing a substantial change in the size or geometric shape of the workpiece.

A method of substantially uniform controlled surface material removal on a non-ferrous metal workpiece, comprising:

• immersing a surface of a non-ferrous metal workpiece in a bath of an aqueous electrolyte solution including a concentration of citric acid less than or equal to about 600 g/L and a concentration of ammonium bifluoride less than or equal to about 120 g/L, and having no more than about 3.35 g/L of a strong acid;
• controlling the temperature of the bath to be greater than or equal to about 71° C.;
• connecting the workpiece to the anode of a DC power supply and immersing a cathode of the DC power supply in the bath;
• and
• applying a current across the bath;
• continuing the immersion of the surface in the bath and application of current to achieve a uniform controlled amount of material removal from the surface;
• and
• removing the surface from the bath following such controlled removal without causing a substantial change in the size or geometric shape of the workpiece.