Direct production of TiAl3 from Ti/Al-containing oxides precursors by solid oxide membrane (SOM) process

Abstract

TiAl3 intermetallic has been successfully synthesized by the electrochemical deoxidation of the Ti/Al-containing oxides precursors including TiO2/Al2O3 mixture and titanium-rich slag/Al2O3 mixture at 1000 °C and 3.8 V in molten CaCl2. A solid oxide membrane (SOM) tube filled with carbon-saturated liquid tin was served as inert anode, and the pressed pellet of Ti/Al-containing oxides precursors was used as cathode during the electrochemical deoxidation process. The results show that the reduction proceeds through a serious of individual stages, which mainly involve the formation-decomposition of calcium titanium/aluminum oxides and the formation of TiAlx alloys. The analysis of the partially reduced cathode pellet confirms that the three phases interlines (3PIs) reaction area gradually expands from the pellet's surface to its centre. The morphology of the TiAl3 obtained from TiO2/Al2O3 precursor exhibits a homogeneous nodular structure. The final product produced from the titanium-rich slag/Al2O3 precursor contains TiAl3 and Ll2 Ti0.75Fe0.25Al3. In addition, the porous TiAl3 with high porosity can be prepared by using NaCl as the space-holder material. The results demonstrate that the SOM process has the potential to be used for the facile production of Ti-Al alloys from complex oxides precursors.