Wire and wire-mesh plating
Whiskers are monocrystals that grow out of the tin layer and can thus cause electrical short circuits on circuit boards or in plug-in connectors.
The danger of whisker formation exists in galvanically separated pure tin layers on copper or copper alloys. Critical storage conditions (e.g. temperature changes, humidity) accelerate the growth of an irregular intermetallic phase between tin and copper or the copper alloy. This creates compressive stresses within the tin layer which can lead to whisker formation. Additional stresses from the exterior, which cannot be fully avoided in processing, increase this phenomenon.
Pure tin coatings with minimised whisker risk
The formation of an irregular intermetallic phase can be minimised or even prevented with selected production technologies:
- Nickel as barrier layer (only galvanically)
- DC (Double Coating) – a pure tin coating developed by EDELHOFF (galvanic, nickel-free), distinguished by an evenly formed intermetallic phase
- Fuzing of the galvanic tin layer
- Hot-dip tinning