Case 713 ยท Public preview
Entrapped Activated Flux Can Corrode a Brittle Intermetallic Joint from Within
A gold-indium soldered assembly fractured through an intermetallic region containing voids, residual flux, and widespread corrosion features.
SEM fractographyEDSMetallographic sectioningIntermetallic-layer examinationCorrosion morphology assessment
What the evidence preview establishes
Entrapped zinc-bromide-activated soldering flux most likely corroded the AuIn intermetallic compound and produced a corrosion-induced fracture through the joint.
Why this case matters
Voids in a reactive solder system are not only mechanical discontinuities; they can retain activated flux. Examine fracture chemistry and intermetallic grain boundaries together, then reduce flux entrapment and excessive gold thickness when AuIn corrosion is confirmed.
Full evidence reserved for MEMBER and STOREThe complete case includes the evidence sequence, four interpreted figures, alternative explanations, limitations, and practical application guidance.