Preparing aluminium-scandium inter-alloys during reduction process in KF-ALF3-SC2O3 MELTS

Abstract

Al-Sc Alloys have attracted much attention in recent years due to their great potential in many advanced applications. In this work, Al-Sc alloys were prepared on liquid Al cathode in KF-AlF3-Sc2O3 (CR=1.22) melts during reduction process. Scanning electron microscope (SEM) and Inductively coupled plasma atomic emission spectroscopy (ICP-AES) showed that the primary Al3Sc were highly faceted and Sc contents were 0.44 and 0.73 wt.% in the alloys produced at 750 °C with current density of 0.5 and 1.0 A/cm2, respectively. At 1.0 A/cm2, Sc content increased to 0.95 wt.% at 800 °C and 1.27 wt.% at 850 °C. But higher mass loss from the melts was found with increased operating temperatures. Cyclic Voltammetry and Linear Sweep Voltammetry studies demonstrate that the reduction of Sc3+ occurs at liquid Al cathode and Al3Sc formation is electrochemically irreversible. In addition, the effect of ultrasound on the Sc distribution was also investigated.