Al-Sc Alloy Production using Metal Ion Plasma

In chemical reactions using microwave irradiation, local concentration of electric and magnetic fields between particles, such as catalysts and powders, increases the reaction rate and lowers the temperature of the reduction reaction of the entire sample. The concentration of electric and magnetic fields between solid particles and plasma is believed to cause such reactions. In high-temperature reactions between individual particles, plasmas are directly involved in and accelerate chemical reactions, whose reaction temperatures reportedly become lower than the reduction reaction temperatures under normal heating. Therefore, using a cylindrical cavity in the TM110 mode at 2.45 GHz with a strong magnetic field, a Mg plasma was generated from Mg rods, and ten pellets of the Φ13×5 mm sample mixed with scandium oxide and aluminum powder were placed in an induction coil at 13.56 MHz and were reduced at 700 °C for approximately 1 h, with a conversion rate of 42%. Despite the low conversion rate, scandium oxide was successfully reduced at a low temperature by Mg plasma and induction heating without necessitating the use of additional solvents. The low conversion rate was caused by an insufficient supply of Mg, which could be resolved by increasing the reaction time. This experiment confirmed that Mg ions contribute to the lower temperature of the reduction reaction and that the generation of a Mg plasma by microwaves and the heating of the reaction zone by radiofrequency bands offer the prospect of fabricating a system larger than that obtained using microwaves alone.