Defect Description
Connecter contacts where corrosion process(es) has/have taken place that the mechanical contact is weakened but electrical contact remains that make them undetectable as a defective contact. It is possible that corroded products can consolidate the mechanical contact but the list of tests below only cover a weakened contact.
Defect Formation Process(s)
Common conditions include defective designs, manufacturing defects and ingress of moisture and contaminants. Different common defects/design of connector contacts are prone to corresponding types of corrosions. General corrosion processes are accelerated by moisture and/or contaminants (corrosive elements, e.g. Chlorine, Sulphur, Potassium) that got into contact with connectors due to improper manufacture control processes.
Mechanical strength of a connector could be weakened after corrosion has taken place due to the formation of brittle corrosion products on the surface coating as well as the voids left in the base metal anode [1-3].
|
List of Tests to Precipitate this Defect |
Failure Acceleration |
Likelihood to Precipitate this Defect (condition) |
Failure Mechanism(s) |
|
Thermal Shock |
• Cyclic thermal mechanical stress accelerates crack initiation and growth due to CTE mismatch • Thermal mechanical stress can cause fracture of the corrosion product. |
✇ |
Thermal Fatigue Thermal Mechanical Overstress |
|
Random Vibration (RS/ED) |
• Random Vibration can accelerate fatigue cracking of the corrosion products. • Random Vibration can cause fracture of the corrosion products. • Random Vibration can increase micromovement of corrosion products and contacts which accumulates and increases contact resistance of the connector. |
✔/✇ |
Mechanical Fatigue Mechanical Overstress Abrasion of Contact Surface |
|
Combined Environment |
• Combination of Thermal Shock and Random Vibration |
✔ |
Combination of Thermal Shock and Random Vibration |
References
[2] Davis, G.O. Corrosion of Electrical Connectors. Battelle Columbus Laboratories, 1986.
[3] Schweitzer, Philip A. Corrosion Engineering Handbook. Boca Raton: CRC Press, 2007.
[4] Zhang J. G., “ Effect of Dust Contamination on Electrical Contact Failure”, Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts, 2007.
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