In hot-dip tinning, strip with a cleaned and activated surface passes through a molten tin bath. After leaving the bath, a contactless air stream levels the liquid tin to the target thickness. Inline X-ray fluorescence measures coating thickness on both sides continuously throughout the process.
The result is a two-layer coating structure: an intermetallic phase (IMP) of Cu₃Sn and Cu₆Sn₅ bonds the tin metallurgically to the base material; a free tin layer above the IMP provides the contact surface.
This structure delivers four performance characteristics that conventional electroplated tin cannot replicate:
What it is: SnPUR® is a pure hot-dip tin coating. The structure consists of a Cu₆Sn₅ intermetallic phase bonded to the base material, with a free pure tin layer on top.
When to use it: Applications requiring low contact resistance and good solderability at standard operating temperatures.
Key characteristics:
What it is: SnTEM® starts as a standard hot-dip tin coating and is then transformed by a subsequent heat treatment into a fully intermetallic CuSn compound. No free tin remains.
When to use it: Multipole connectors with high mating cycle requirements where insertion and withdrawal forces must be minimized and wear resistance maximized.
Key characteristics:
What it is: SnTOP® is a tin-silver hot-dip coating containing approximately 4% silver. The silver content causes precipitation hardening of the coating layer.
When to use it: Applications at elevated temperatures (up to 160 °C) where a combination of reduced insertion forces, fretting corrosion resistance, and solderability is required – as a cost-effective alternative to silver-plated surfaces.
Key characteristics:
The core characteristic of our hot-dip tinned coatings is the formation of a specialized intermetallic phase (IMP) between the base material and the tin layer.
We provide a wide range of dimensions to suit your specific manufacturing needs: