Susceptor Heating Systems

Overview

Susceptor heating systems use induction heating, which transfers energy quickly, efficiently, and effectively. Induction heating is typically used with metals or other electrically conductive materials where electromagnetic current is caused to flow through the material via direct induction coupling, and the resistance of the material to the electric current flow creates heat. Nonconductive materials can be induction heated by employing a conductive susceptor that captures electromagnetic current and transfers heat to contained parts or materials through conduction and/or radiation. Susceptors such as graphite and silicon carbide are often used because they offer machinability, high resistivity, and an operating temperature range of up to 3000ºC (5430ºF). Susceptors can also be made from molybdenum, tantalum, stainless steel, niobium, and platinum, as well as other conductive materials. Example process materials include composites, ceramics, aluminides, nitrides, carbides, oxides, semiconductor, reactive metals, graphite, and specialty chemicals. Continuous-processing equipment configurations incorporating induction susceptor heating are typically horizontal, vertical, or circular in design. Multi-physic, finite element analysis (FEA) modeling is utilized to determine the location of required thermal boundaries within heating and cooling zones. Thermal profiles can be established, maintained, and controlled through immersion thermal couples, optical pyrometers, digital imagery, and other devices to form a closed-loop system, and continuous systems typically incorporate multiple zones for heating, cooling, soaking, and other process functions. Reaction gases can be introduced and off-gas byproducts removed, and controlled atmosphere or vacuum processing with multiple zones can be accommodated with isolation valves or other zone interlocks. Ajax TOCCO Magnethermic Corporation holds ISO 9001:2015 certification dated Dec 15, 2022 valid until December 2028, and the Detroit Support Center holds ISO 9001:2015 certification dated Dec 15, 2022 valid until April 2028. Susceptor heating is described for high-temperature, controlled atmosphere thermal processing and can accommodate applications requiring such processing. Continuous thermal processing using susceptor heating is noted to typically provide the lowest cost of ownership and greater product throughput compared to conventional batch processing techniques. Example processes supported include sintering, recrystallization, purification, annealing, carburizing, graphitizing, nitriding, oxidizing, calcining, CVD, and fluidized bed reactors. Processes can be run with introduced reaction gases and off-gas removal, and can be performed in controlled atmosphere or vacuum conditions with zoned isolation valves or other interlocks.