Electrolyte composition for electropolishing niobium and tantalum and method for using same

Abstract

The electrolyte composition and electropolishing method for electropolishing surfaces of metals and their alloys, in particular surfaces of niobium, niobium containing alloys, tantalum, tantalum containing alloys is disclosed. The electrolyte composition comprises methanesulfonic acid and hydrofluoric acid. Said electrolyte composition make possible to electropolish niobium, niobium containing alloys, tantalum and tantalum containing alloys to the best quality ever by eliminating problems of hydrogen absorption and sulfur contamination o the workpieces.

1 . The electrolyte for electropolishing of surfaces of metals and metals alloys that are selected from group comprising niobium, niobium alloys, tantalum and tantalum alloys, wherein the electrolyte composition comprises methanesulfonic acid 70 wt % and hydrofluoric acid 48 wt %. 
   
   
       2 . The electrolyte as claimed in  claim 1 , wherein it contains methanesulfonic acid in concentration of from 50 to 95 vol %, preferably 70 to 80 vol %. 
   
   
       3 . The electrolyte as claimed in  claim 1 , wherein it contains hydrofluoric acid in concentration of from 5 to 50 vol %, preferably 20 to 30 vol %. 
   
   
       4 . The electrolyte as claimed in  claim 1 , wherein the electrolyte does not contain any other ingredient. 
   
   
       5 . A method for electropolishing workpieces of niobium, niobium alloys, tantalum and tantalum alloys, wherein an electrolyte as claimed in  claim 1  is used. 
   
   
       6 . The method as claimed in  claim 5 , wherein electropolishing is carried out at temperature between 10° C. and 50° C., preferably 25° C. 
   
   
       7 . The method as claimed as in  claim 5 , wherein electropolishing is carried out using direct current (DC) of constant voltage between 5 V to 15 V, preferably 10 V.