The invention relates to a
thermal insulation system with long service life for a
silicon carbide crystal growth furnace. On the basis of composite
thermal insulation of soft / hard felts, a C / C
composite material is innovatively selected as an innermost layer thermal insulating material, excellent characteristics that the mechanical properties are increased with temperature raised, the
linear expansion coefficient is small, the ablative resistance is excellent, the
damage tolerance is high, and adhesion does not occur under a high temperatures are utilized, a cylinder with a thickness of 0.5mmis adopted, the upper and lower ends are
cut, two fractures exist per round, the fracture width is 1-1.5mm, so that formation of a
closed circuit is avoided, because the C / C
composite material has anextremely small
linear expansion coefficient, the fractures are not closed under a high temperature, and a low obstruction to alternating
magnetic field penetration is realized; and damage on thermalinsulation of each layer at an outer side caused by thermal
corrosion,
thermal shock,
chemical corrosion and the like is fully reduced, the overall service life and stability of the thermal insulationsystem are improved, the stability period of a
thermal insulation system can be increased from previous 800h to 1500h or more, and people only need to replace an innermost layer thermal insulating soft felt to restore a
stable state, and the overall service life is extended by 1 time or more.