Sacrificial coatings are applied to surfaces both by bath and via selective brush plating to protect the underlying substrate from corrosion. The sacrificial coating corrodes in preference to the substrate, a property which is especially important when the substrate is scratched or damaged.
Cadmium has long been used to provide this protection for structures, equipment, and fasteners. After all, it is easy to plate and it has desirable properties that include corrosion protection, lubricity, anti-galling, electrical conductivity, and low hydrogen embrittlement.
Government mandates and environmental concerns are driving manufacturers to find alternatives for cadmium, Developing a suitable replacement for cadmium plating is essential for the protection of high-strength steel components found on aircrafts. The success of the tin-zinc alloy in the automotive industry should help provide the impetus to advance its application as an alternative for the cadmium plating in the aircraft industry.