Wire and wire-mesh plating
- Melting point: 232°C
- ROHS conformity
- low abrasion resistance
Tin is one of the most frequently used surfaces; it combines good electrical properties with very good soldering capacity. The following surfaces are possible:
- hot-dip tinned, shiny
- galvanic, shiny tin-plating
- galvanic, matte tin-plating
- galvanic, fused, shiny
The low abrasion resistance is disadvantageous but can be counteracted with modifications.
- Corrosion protection
- Great hardness
- Barrier layer
Nickel generally serves as a protective layer against corrosion, but the great hardness also gives it very good wear characteristics. Another application area is the use as barrier layer between copper materials and tin ( whisker protection) or gold (diffusion).
- very good conductivity
Galvanically separated copper is used to improve conductivity because of its very good electrical characteristics. Other applications are as protective layer (e.g. drawing aid) and as intermediate layer.
- very good conductivity
- very good corrosion properties
- Tendency to oxidate
Silver is another material with very good contact and corrosion properties. However, silver tends to oxidate which deteriorates the surface characteristics. This can be prevented by a coating with passivation agents.
- best corrosion properties
- very good electrical properties and high soldering capacity
- high density
- high price
High tarnishing and corrosion resistance, good electrical conductivity and low contact resistance make gold an ideal contact and soldering material. Since gold very quickly diffuses in copper materials, a nickel undercoat for gold coatings is the state-of-the-art for copper materials, it simultaneously increases abrasion resistance. The high density of 19.3 g/cm3 and the high price must be regarded as a disadvantage.
Palladium and palladium/nickel
- Replacement of gold as final layer
- Great hardness, low ductility
Because of the high gold price, palladium as a metal with excellent contact properties can replace gold in part. But gold flash (< 0.1 mµ) is used almost exclusively as the final layer here. Using it as an intermediate layer in place of nickel can also be feasible for specific applications.
- well solderable
- Melting point lower than that of pure tin
- less tendency to Whisker
- no ROHS conformity
- for special applications
Tin/lead (in different alloys) is known for an extremely low tendency to whisker formation and is therefore still used for a number of special applications such as e.g. in aerospace. This coating can be applied molten as well as galvanically.
We can apply a number of low-melting solders (e.g. tin-indium, tin-bismuth) in a molten manner. The main applications here are in solar engineering.
|Process||Metal||Hot-Tin Dipping||Electroplating||Melting- point (°C)|
|matt||bright (matt + die burnished)||bright||reflowed||Inter- mediate layer||Top layer|
|Tin / Lead "L5"||Sn95Pb5||X||X||X||X||X||220|
|Tin / Lead "L40"||Sn60Pb40||X||X||X||X||X||185|
|Tin / Lead "L70"||Sn30Pb70||X||X||X||X||X||270|
|Tin / Indium||In52Sn48||X||118|
|Tin / Bismut||Bi58Sn42||X||138|