The tin-plating process is used extensively to protect both ferrous and nonferrous
surfaces. Tin is a useful metal for the food processing industry since it is
non-toxic, ductile and corrosion resistant. The excellent ductility of tin
allows a tin coated base metal sheet to be formed into a variety of shapes
without damage to the surface tin layer. It provides sacrificial protection for
copper, nickel and other non-ferrous metals, but not for steel.
Tin is also widely used in the electronics industry because of its ability
to protect the base metal from oxidation thus preserving its solder-ability. In
electronic applications, 3% to 7% lead may be added to improve solder-ability
and to prevent the growth of metallic "whiskers" in compression
stressed deposits, which would otherwise cause electrical shorting. However, RoHS
(Restriction of Hazardous Substances) regulations enacted beginning in 2006
require that no lead be added intentionally and that the maximum percentage not
exceed 1%. Some exemptions have been issued to RoHS requirements in critical
electronics applications due to failures which are known to have occurred as a
result of tin whisker formation.