Is used as a base plating for improved adhesion,
activation of passive substrates or as an insurance step in
the cleaning cycle. Copper is also used for decorative purposes
because of its aesthetically pleasing warm color.
A very important engineering value of copper
is its ability to prevent hardening of the base material it
is applied to, when used as a mask or stop off in thickness
exceeding .0005 of an inch. When areas of a part require protection
from hardening during the heat treating process, copper is
an excellent choice.