MIL-M-45202
Magnesium is usually
treated with an anodic or a chromic coating prior to the application of
an organic finish.
Coatings range
from
thin clear to light gray-green, to thick dark green coatings. The clear
coatings are used a base for subsequent clear lacquers or paints to
produce a final appearance similar to clear anodizing on aluminum.
The light gray-green
coatings are used in most applications which are
to be painted. The thick, dark green coating offers best combination of
abrasion resistance, protective value and paint base characteristics.
The HAE anodic finish is probably the hardest coating available for
magnesium. They exhibit stability at high temperatures and good
dielectric strength. Excellent paint base. Requires resin seal or paint
for maximum corrosion protection.
Type I:
Light coating.
Class A:
(.0002" ) Tan coating (HAE)
Grade 1:
Without post treatment (dyed).
Grade 2:
(.0003") With bifluoride-dichromate post treatment
Class C:
Light green coating (Dow #17)
Type II:
Heavy coating
Class A:
(.0015") Hard brown coating (HAE)
Grade 1:
Without post treatment
Grade 3:
With bifluoride-dichromate post treatment
Grade 4:
With bifluoride-dichromate post treatment including moistheat aging.
Grade 5:
With double application of bifluoride-dichromate post treatment
including moist heat aging.
Class D:
(.0012") Dark green coating (Dow #17)
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