Synthesis of an Aluminum–Erbium Master Alloy from Chloride–Fluoride Melts

Abstract

Available foreign power-intensive technologies and the absence of domestic production technologies for aluminum–erbium master alloys intended for improving the physicomechanical properties of aluminum alloys make the development of aluminothermic reduction technology of chloride–fluoride melts actual for manufacturing erbium compounds. Thermodynamic analysis of reduction processes is performed for various erbium compounds. Taking into account the physical and chemical properties of erbium compounds, a starting compound, namely, erbium fluoride is found to be preferable. The aluminothermic reduction of the compound from its mixture with sodium fluoride and potassium chloride to form the Al₃Er intermetallic compound is characterized by a high thermodynamic probability. Since data on thermodynamic parameters for erbium complex compound are scanty, they are determined by an indirect method. Experimental data on the aluminothermic preparation of an Al–Er master alloy at temperatures of 750–900°C using melts differing in the ErF₃/NaF ratio and the KCl content are reported; the structure and the phase composition of the prepared master alloy are studied. The phase composition of the flux used for the preparation of the Al–Er master alloy is determined.