Case 1806 ยท Public preview
A Weak Manganese-Dioxide Layer Can Reduce Tantalum-Capacitor Surge Margin
One tantalum capacitor was severely degraded and three others were low-resistance shorts.
Electrical testingOptical microscopyMicrosectioningSEMEDSFailed-control comparison
What the evidence preview establishes
Thin, granular manganese-dioxide layers increased local resistance and encouraged hot-spot formation during surge current. Shorted devices developed extensive tantalum-manganese alloying, oxygen generation, and rupture or melting of the overlying silver layer.
Why this case matters
Separate susceptibility from trigger in tantalum-capacitor failures. Compare cathode morphology across failed and functional parts, locate alloying and gas-driven rupture, and review surge current and voltage derating together.
Full evidence reserved for MEMBER and STOREThe complete case includes the evidence sequence, four interpreted figures, alternative explanations, limitations, and practical application guidance.