Performance testing can only be performed after magnesium oxide refilling has been completed and sintered, and then completely cooled to room temperature. The entire process typically takes 3–5 hours. The exact time depends on the strict adherence to the sintering and cooling processes.
Key Steps and Timeline Before Performance Testing
Stage Time Description
Sintering Holding 1–2 hours Grain recrystallization completed in an inert atmosphere at 800–1000℃
Natural Cooling in Furnace 1–2 hours Cooling from high temperature to <200℃ to prevent thermal stress cracking
Cooling to Room Temperature After Removal from Furnace Approximately 30–60 minutes Ensuring the component temperature stabilizes at around 25℃ to avoid testing errors
Testing can begin as early as 3 hours after the start of sintering, but it must be confirmed that the component has completely cooled and the environment is dry (RH ≤ 30%).
Recommended Test Items and Sequence
Cold Insulation Resistance Test (500V DC)
Standard: ≥500 MΩ Use a calibrated 2500V megohmmeter to eliminate surface leakage interference.
Cold Withstand Voltage Test
Standard: AC 2000V, no breakdown or flashover within 1 minute. Must be performed after the insulation resistance is qualified to prevent equipment damage.
Hot and Humid Tests (Subsequent Verification)
Hot: Measure insulation within 2 seconds of power failure after 30 minutes of operation; ≥200 MΩ.
Humid: Retest after 48 hours at 40℃ and 95%RH; ≥200 MΩ. Testing without sufficient cooling may lead to data distortion or instrument misinterpretation, posing a safety hazard.
