Synthesis of Silumins in KF-AlF3-SiO2 Melts

The possibility of obtaining silumins in KF-AlF3 melts via SiO2 additions at a temperature of 720 degrees C is investigated. Silumins with high silicon contents (up to 37 wt%) can be obtained in KF-AlF3-SiO2 melts via the electrochemical co-deposition of aluminum and silicon on a graphite cathode in both galvanostatic and potentiostatic modes. Electrode processes are studied with cyclic voltammetry. It is shown that the peak of silicon cathode deposition with the addition of SiO2 is fixed at a potential of about -0.8 V (in relation to the CO/CO2 reference electrode). The expansion of the silicon allocation potential area from a value of -0.5 V with increasing concentration of SiO2 in the melt indicates the complex ionic structure of the melt. (C) 2016 The Electrochemical Society. All rights reserved.