Heating a Graphite Susceptor in a Bell Jar
Research Objective
To heat a graphite susceptor to 1200°C through the use of a helical inductor with a minimum inside diameter of 4”. Time to temperature and temperature gradients throughout the sample are of special concern.
Parts & Materials Description
Graphite susceptor “boat” measuring 4” wide, 2.5” long, 0.5” thick
Temperature Required
1200°C
Induction Heating Equipment
Bell jar protective atmosphere heating system with 7.5 kW induction supply, IR optical pyrometer, specially designed inductor (coil)
Operating Frequency
123 kHz
Heating Procedure
A specially-designed seven-turn helical inductor was used to provide optimal heating efficiency. An optical pyrometer was utilized to ensure accurate temperature measurement. Initial tests were conducted to establish a heating profile and determine time to temperature. RF power was applied for 7 minutes. The susceptor reached a temperature of 1200°C with a temperature gradient of 55°C across the boat.
Conclusion
Successful, even heating was achieved by heating the graphite susceptor with the 7.5 kW power supply in a protective atmosphere.
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