Electrochemical Deoxidation of Titanium and Its Alloy Using Molten Magnesium Chloride

Oxygen was directly removed from pure titanium and a Ti-6Al-4V alloy by electrolysis in molten MgCl2 at 1173 K (900 degrees C), where the metal being refined was the cathode and a graphite rod was used as the anode. By applying a voltage of approximately 3 V between the electrodes, commercially pure titanium, containing 1200 mass ppm oxygen, and the Ti-6Al-4V alloy, containing 1400 mass ppm oxygen, were deoxidized to 500 mass ppm or less. Under certain conditions, extra-low-oxygen titanium (as low as 80 mass ppm oxygen) was obtained using this electrochemical technique. The results obtained in this study indicate that the electrochemical deoxidation of titanium in molten MgCl2 is feasible and applicable not only to the refinement of primary metals, but also for upgrading machined titanium products and recycling metal scraps. (C) The Minerals, Metals & Materials Society and ASM International 2016