Metals
Metals are made from mineral ores that
are typically mined and forged from the ore state. They are opaque, fusible, ductile, strong, and
lustrous materials. During working, smelting changes the chemical
makeup of the mineral ores. With the removal of oxygen, the material
changes from its "ore state" to its "metallic
state." Metals are good conductors of heat and electricity.
Common metals are iron, copper, silver, and gold.
The corrosion process is electrochemical process similar to the
action of a battery. Any time two
different metals are in contact, either physically, as a part
of an alloy (a mixture of metals, such as sterling silver), or
through an electrolyte (any solution containing ions, such as
water), they form a galvanic cell based on the differences in
electrical potential. The anode (less noble of the two metals)
gives up electrons (negatively charged ions, seen above as red
dots) to the cathode (more noble of the two metals). At the same
time, positively charged metal ions (seen above as blue dots)
are stripped from the anode and go into solution. The surface
of the cathode is protected from corrosion at the expense of
the anode. This process can proceed at any scale, and does not
require liquid water - water vapor alone is sufficient.
Metal alloys contain a mixture of two
or more metals. Alloying two metals
alters the working properties of the metals such as melting point,
color, ductility, surface characteristics, brittleness, etc.
Common alloys are sterling silver, brass, bronze, steel, wrought
iron, and pewter.
More Resources
(pdf)
Caring for Copper
Alloys
Caring for Firearms
Caring for Iron
Alloys
Caring for Silver
Notes on Treating
Tools
Pinhole
Corrosion in Sprinkle Systems
