Small additions of Lead in bronze and other copper alloys found at
archaeological sites, are believed to have been added as a diluents
to the more precious copper, and/or to reduce the melting
Some modern copper, aluminum and steel alloys use
small additions of Lead to improve machinability.
Some aluminum alloys are formulated with a Lead addition of less
than 4% for improved machinability. These are mainly used by smaller
specialized companies for the
automotive industry. The market share of these products is estimated
at 0.3% (maximum) of the aluminum used in automotive applications,
with a decreasing trend with time.