Sintering after refilling requires a holding period of 1-2 hours. This is a crucial step to ensure sufficient recrystallization of magnesium oxide grains and the formation of a dense and stable insulating structure.
Necessity and Process Requirements of Holding
Holding time: 1-2 hours, conducted in an inert atmosphere (such as nitrogen) at 800-1000℃;
Core functions:
To promote the recrystallization process of magnesium oxide particles, increasing structural density;
To eliminate internal stress, enhancing the voltage resistance and thermal stability of the insulation layer;
To prevent microcracks or localized porosity caused by uneven temperature.
Holding is an indispensable step in the sintering process, directly affecting the lifespan and safety of the heating element after repair.
Complete Sintering Process Timeline
|
Stage |
Temperature |
Time |
Description |
|
Heating |
Room temperature → 800–1000℃ |
1–1.5 hours |
Uniform heating, avoiding thermal shock |
|
Holding |
800–1000℃ |
1–2 hours |
Key stage: Achieving grain recrystallization |
|
Cooling |
1000℃ → <200℃ |
1–2 hours |
Natural cooling within the furnace, preventing cracking |
The entire sintering and cooling process must be completed in a dust-free, humidity-controlled (RH≤30%) cleanroom to ensure no contamination.
