Three mixtures of albite (Ab) and anorthite (An) were melted and then held at a constant temperature (1200°C) for varying lengths of time in a 2.45 GHz electromagnetic field. The same mixtures of albite and anorthite were held at 1200°C for 64 hours and 128 hours in a conventional furnace. All heated charges were air quenched after a desired duration time at 1200°C.
All three conventionally heated compositions of albite and anorthite showed the presence of crystalline phase. Only a trace of crystalline phase was found in 90 wt% Ab-10 wt% An at 1200°C for 64 hours in a conventional furnace. The amount of crystalline phase was found to increase as the anorthite content was increased. The mixture of 72 wt% Ab-28wt% An held at 1200°C for 128 hours in a conventional furnace had the largest amount of crystalline phase.
For the samples heated in a 2.45 GHz electromagnetic field, all compositions heated for 1 hour to 64 hours and the 90 wt% Ab-10 wt% An heated for 128 hours showed no trace of crystalline phase. The compositions of 81 wt% Ab-19 wt% An and 72 wt% Ab-28 wt% An showed some crystalline phase, but the amount of crystalline phase was much less than the samples processed in a conventional furnace.