An induction furnace includes a cylinder, a top and bottom cover that seal
the top and bottom ends of the cylinder, and coolant passages within the
cylinder and the covers. The induction furnace further includes a power
supply and a coil. The coil surrounds the chamber and is hollow to allow
flow of coolant therethrough. A susceptor susceptible to induction
heating is located in the chamber and includes top and bottom pieces. A
thermal insulator is disposed between the susceptor and the inner walls
of the chamber and can be formed of a fused quartz cylinder within which
the susceptor and the workpiece are contained. The thermal insulator can
also include infrared reflectors and insulating members on the ends of
the susceptor to reduce heat leakage to parts of the furnace outside of
the susceptor.