ELECTROLYTIC POLISHING METHOD AND ELECTROLYTIC POLISHING LIQUID

To provide an electrolytic polishing method and an electrolytic polishing liquid without using any concentrated sulfuric acid or hydrofluoric acid.SOLUTION: A method of electrolytically polishing at least one of niobium, titanium, and tantalum is a method in which an electrolytic treatment is performed in an electrolytic solution including a glycolic acid solution in which a specified quantity of ammonium fluoride is dissolved. The glycolic acid solution is 30-90 mass% of the electrolytic solution, and the ammonium fluoride is 2-10 mass% of the glycolic acid solution in outer percentage. The electrolytic treatment is performed at the temperature of between a room temperature and 50°C, and at the voltage of 25 V or lower. An oxide film is formed on the surface of a metal such as niobium by using the glycolic acid. The oxide film is shaved off by applying an electric current to the ammonium fluoride. An operator can easily handle the glycolic acid and the ammonium fluoride because they are not designated as deleterious substances. In addition, the finish state of polishing in this case is not inferior to that in the case where a concentrated sulfuric acid or a hydrofluoric acid is used.SELECTED DRAWING: Figure 8 【課題】濃硫酸やフッ酸を使用しない電解研磨の方法と電解研磨液を提供する。【解決手段】ニオブ、チタン、タンタルの少なくとも一種の電解研磨をする方法であって、グリコール酸溶液にフッ化アンモニウムを所定量溶解させた電解液中で電解処理をする方法。前記電解液のグリコール酸溶液は、３０〜９０質量％であり、前記フッ化アンモニウムがグリコール酸溶液に対して外掛けで２〜１０質量％である。また、当該電解処理は室温から50℃、２５V以下で実行される。上記グリコール酸でニオブ等の金属の表面に酸化膜が形成される。この酸化膜を、フッ化アンモニウムに電流を流すことによって削り取る。グリコール酸およびフッ化アンモニウムは劇物指定はされておらず、作業者の取り扱いは容易となる。加えて、研磨の仕上がり状態は濃硫酸とフッ酸を使用した場合と遜色はない。【選択図】図８