Reactivity of commercial silicon and silicides towards copper(I) chloride. Effect of aluminium, calcium and iron on the formation of copper silicide

Abstract The reaction of CuCl with silicon, containing Al, Fe and Ca as impurities, or with silicides (Si 2 Ca, Si 2 Fe, Si 2 Al 2 Ca, Si 8 Al 6 Fe 4 Ca) has been investigated in the temperature range 200–300°C. For the reaction between CuCl and commercial Si, it was found that, at 282°C, aluminium promotes the reaction between Cu 3 Si and CuCl while the rate of consumption of Cu 3 Si is greatly reduced by the presence of iron. The combined action of these two impurities leads to the formation of more copper–silicon alloy. In the presence of mixed silicides, the reaction with CuCl also leads to the formation of Cu 3 Si. For the quaternary Al–Ca silicide containing iron the rate of formation of Cu 3 Si is not increased, which allows us to attribute a stabilizing effect to iron.