Abstract: A microwave furnace that can operate at least 1700° C. having a furnacing chamber within a retaining cavity. The chamber is at least partly surrounded by microwave transparent insulation. At least one susceptor is at least partly between the insulation and the chamber. The susceptor at least in part is a specially formulated sintered coarse grain polycrystalline ? alumina capable of absorbing microwave energy from room temperature to its maximum use temperature. The furnace has a power system providing microwave energy to activate the susceptor. A temperature sensor may be provided that has an infrared channeling tube to conduct an infrared signal from the chamber to a pyrometer for converting the infrared signal to an electrical signal proportional to temperature within the microwave chamber. The electrical signal is then used to signal the power supply to control temperature by controlling energy to the susceptor.

Abstract: A microwave furnace that can operate at least 1700° C. having a furnacing chamber within a retaining cavity. The chamber is at least partly surrounded by microwave transparent insulation. At least one susceptor is at least partly between the insulation and the chamber. The susceptor at least in part is a specially formulated sintered coarse grain polycrystalline ? alumina capable of absorbing microwave energy from room temperature to its maximum use temperature. The furnace has a power system providing microwave energy to activate the susceptor. A temperature sensor may be provided that has an infrared channeling tube to conduct an infrared signal from the chamber to a pyrometer for converting the infrared signal to an electrical signal proportional to temperature within the microwave chamber. The electrical signal is then used to signal the power supply to control temperature by controlling energy to the susceptor.