Meaning
An electroplated ternary alloy finish composed of copper, tin, and zinc provides a non-magnetic, highly conductive, and corrosion-resistant coating for RF interconnect hardware. The surface finish widely known as tri-metal plating acts as a cost-effective alternative to silver or gold on coaxial connector bodies and internal filter cavities. The effectiveness of the finish diminishes when subjected to extreme sliding wear that exposes underlying base metals.
Ternary Composition
Electrodeposition from specialized cyanide or non-cyanide alkaline baths co-deposits approximately fifty-five percent copper, thirty percent tin, and fifteen percent zinc. Deposits of tri-metal plating combine the electrical conductivity of copper, the corrosion resistance of tin, and structural hardness into a bright white alloy finish.
Intermodulation Control
Ferromagnetic nickel platings introduce non-linear magnetic hysteresis that generates severe passive intermodulation in high-power RF signal paths. Because tri-metal plating is completely non-magnetic, it eliminates hysteresis losses and provides low signal distortion across multi-carrier communications bands. The hard ternary deposit resists tarnishing better than pure silver, maintaining stable surface resistance over long outdoor service deployments.
Intermodulation test benches verify low distortion signatures on plated connector housings.
Deposition Verification
Quality assurance procedures mandate regular measurement of plating thickness, alloy ratio, and corrosion resistance. Standard specifications for tri-metal plating require two to four micrometers of alloy deposit over a copper or brass substrate. Inspection certificates confirm non-magnetic properties using sensitive Gauss meters prior to final handover.
