This is a summary of SEM Lab, Inc.’s data on connectors analyzed over the past twenty-seven years.  The most frequent cause of connector problems is shown in descending order.


The most frequently occurring issue affecting connectors is contamination (Fig. A), which suggests that clean manufacturing environments and strict contamination control measures are a necessity.  However, the use environment is just as important and much more difficult to control.


Fig. A – Contamination on connector pin.

Contamination appears frequently as a cause of failure. It can occur on contact surfaces, socket pins, and within connectors. Contaminants are typically from metallic debris due to wear, or chemicals from processing or the use environment, or polymer contamination from processing or material outgassing. Contamination can lead to increased resistance, corrosion, and eventual failure of electronic connectors.

Wear and Fretting Corrosion

Wear on connector and socket pins is the next most frequent cause of failure. Fretting corrosion, which is a type of wear that occurs at the contact interfaces due to slight oscillatory movement (i.e. vibration), can lead to poor electrical contact and failure (Fig. B).


Fig. B – Wear and fretting corrosion on contact surface.

Wear and fretting corrosion are common problems at contact interfaces, highlighting the need for durable materials and design strategies that mitigate fretting.

Material Defects and Plating Issues

Finally, defects in base materials, like defects in Kovar pin base material under the nickel-plating layer (Fig. C), or inadequate nickel under-plating thickness, or thin gold contact plating, suggest a need for stringent quality control in material selection and plating processes.

Fig. C – Defects in Kovar connector pin under nickel plating.


The percentage of analysis task in this laboratory broken down by cause is as shown below …



In conclusion, addressing contamination, wear, and material integrity should be a priority in addressing reliability issues for electronic connectors.


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