Capability
Tin-Zinc Plating
Tin-zinc is a conductive alloy plating containing 65–85% tin with the balance being zinc. The tin acts as a barrier coating that resists corrosion and tarnish; the zinc works galvanically, sacrificing itself to protect the underlying steel even if the coating is breached.
The combination gives the finish two performance traits in one deposit: tin's solderability, conductivity, and clean appearance, plus zinc's sacrificial corrosion protection. It's environmentally safe, neither toxic nor carcinogenic, and is the modern industry-standard alternative to cadmium plating for aerospace, fastener, and automotive applications.
Alloy Composition
65–85% Sn
Cadmium Alternative
Direct Replacement
Bath Chemistry
Alkaline
Processing
Rack & Barrel
A Modern Cadmium Replacement
Built to Replace Cadmium
Cadmium plating delivered the corrosion resistance and solderability that aerospace, defense, and high-performance industrial programs depended on for decades. It's also toxic, carcinogenic, and increasingly restricted under modern environmental regulation. Tin-zinc was developed to deliver the same performance envelope without the hazards.
What Tin-Zinc Replaces
Cadmium
Historically the go-to finish for aerospace fasteners, glass-to-metal seals, and severe-duty hardware. Now regulated under RoHS, REACH, and end-of-life directives across most modern programs.
What CMC Plates Instead
Tin-Zinc
Conductive, solderable, corrosion-resistant, galvanically compatible with aluminum, and environmentally safe. Specified across aerospace, automotive, electronics, and fastener industries as the direct cadmium alternative.
Where Tin-Zinc Fits
Common Applications
Tin-zinc is specified anywhere the combination of solderability, conductivity, corrosion resistance, and galvanic compatibility with aluminum delivers value the single-metal alternatives can't.
- Automotive hardware — brake fittings, cooling pipes, transmission fittings, mounting brackets
- Electronics and electrical assembly — solderable components with extended corrosion protection
- Glass-to-metal seals — where the alloy's controlled expansion behavior matters
- Fasteners — nuts, bolts, rivets, especially where aluminum mating surfaces require galvanic compatibility
- Aerospace and defense hardware — as a cadmium replacement in legacy and current programs
- Tight-tolerance and complex assemblies — including parts requiring post-plate forming
Finish & Performance Details
Passivate, Tarnish, and Whisker Behavior
Tin-zinc accepts trivalent chromate passivation in clear or yellow variants, both fully hexavalent-chromium-free and compliant with RoHS, REACH, and end-of-life vehicle directives. The deposit itself does not tarnish easily, which keeps the finish clean and solderable through long shelf and assembly cycles.
Compared to pure tin, tin-zinc is more resistant to tin whisker formation. The zinc content disrupts the columnar tin grain structure that drives whisker growth, reducing one of the most-cited reliability concerns in modern lead-free electronics. For programs where pure tin's whisker tendency is a documented concern, tin-zinc is often the right answer without giving up solderability.
Specifications & Standards
Standards We Can Meet
ASTM B605
Standard specification for electrodeposited coatings of tin alloys
SAE-AMS-2422
Aerospace material specification for tin-zinc alloy plating
MIL-T-81955
Military specification often referenced for tin-zinc as a cadmium replacement
ASTM B117
Salt-spray testing standard
IATF 16949
Automotive quality management process control across all facilities
RoHS, REACH, ELV, Cadmium-Free
Trivalent chromium passivation, fully compliant with global directives
Replacing cadmium or specifying tin-zinc for a new program?
Send us a drawing, an aerospace or automotive specification, or a part description. We’ll confirm whether tin-zinc is the right fit for your performance envelope and walk through the passivate, alloy, and processing decisions before anything goes on a line.