The doping method is a traditional method for melting scandium intermediate alloys. It involves wrapping a certain proportion of high-purity metal scandium in aluminum, then mixing it with molten aluminum under argon protection, holding it for a sufficient time, stirring it thoroughly, and casting it into an iron or cold copper mold to obtain scandium intermediate alloys. Melting can be done using high-purity graphite or alumina crucibles, and heating methods can be done using resistance furnaces or medium frequency induction furnaces. This method can melt intermediate alloys containing 2% to 4% scandium.
The principle of the doping method is simple, but the melting points of scandium and aluminum differ greatly (Sc is 1541 ℃, A1 is 660 ℃). The aluminum melt needs to be overheated to a higher temperature, making it difficult to prepare intermediate alloy products with stable composition and uniform distribution, and it is also difficult to avoid the burning of scandium. To achieve this, the improvement method is to mix and press the high melting point metal scandium with dispersant, aluminum powder, flux, etc. in advance during the preparation process, and then add them into the molten metal. The dispersant decomposes at high temperature, automatically crushing the agglomerates, which can produce a uniform alloy and reduce the burning loss of the high melting point metal. But overall, the cost of preparing scandium intermediate alloys using high-purity scandium metal as raw material is relatively high, which is difficult for industrial users to accept.
Post time: Nov-24-2023