Thermal field of silicon carbide raw material synthesis furnace and synthesis furnace

The invention discloses a thermal field of a silicon carbide raw material synthesis furnace. The thermal field comprises a crucible main heater, an auxiliary heater, a protective cylinder and a gas circuit pipe, the protective cylinder comprises a protective cylinder side wall surrounding the circumferential direction of the crucible, a protective cylinder bottom wall positioned at the lower part of the bottom of the crucible and a top cover positioned at the top of the crucible, the protective cylinder side wall is positioned between the crucible and the main heater, and the bottom wall of the protective cylinder is positioned between the auxiliary heater and the crucible bottom. By means of the thermal field, raw materials can be evenly heated in the circumferential direction and the bottom area, the situation of local overheating or undercooling is avoided, better temperature uniformity is achieved, the thermal field performance is more stable, and the thermal efficiency is improved. The graphite protectiv