Zinc
Phosphate: Zinc
phosphate by immersion provides
a fine-grained crystalline coating on iron
and steel and is an excellent paint base
providing parts with "bare" rust
protection so they do not have to be
painted immediately.
A zinc phosphate also provides maximum
resistance to corrosion for
paint finish. Medium weight zinc phosphate
coatings are normally used as a lubricant
carrier for less severe cold forming operations
such as tube drawing or sheet reduction.
Heavy weight zinc phosphating provides
an effective base for forming lubricants
and soaps, and rust preventative compounds.
Manganese
Phosphate: The
manganese phosphate processes provides a thick coating
with a large
crystal structure and is mainly used
for engineering components that require break-in or wear-in
and many vehicle and aircraft specifications refer to
manganese phosphating. Typical components include gears,
steering parts and axle
pinions etc which are required to work under heavy loads
often at high temperatures. Manganese coatings tend to
be dark
grey
to black in colour and therefore are often used with
oil as a self-coloured corrosion resistant semi-decorative
coating.
