| Chromic
Anodizing
Color
will vary from light gray to dark gray depending on
alloy. Not as readily dyed as sulfuric anodize.
Salt spray requirement is 336 hours (5% solution per
method B-117 of ASTM). Minimum weight for Type I &
Type IB coatings: Class 1 200 Milligrams/sq.ft. Because
of thinness will scratch easily.
Can be used for inspection of aluminum forgings or
castings by noting evidence of chromic acid bleed
out from laps,
cracks, seams, etc.
|
| Spec. |
Thickness |
Comment |
| MIL-A-8625-F |
0.00002"-0.00003" |
Used
as a base for lacquer, light oil, or wax. For decorative,
optical, and corrosion retardant applications.
|
| Type
I |
------------------------
|
Conventional
coating produced from chromic acid bath. Unless otherwise
specified, coating will be sealed. Metal salt sealants
should not be used on items that will be painted. |
| Type
IB |
------------------------
|
Low
voltage chromimic acid anodizing 22V +2V |
| Type
IC |
------------------------
|
Non-chromic
acid anodize (Not available at alexandria Metal Finishers.). |
| Class
1 |
------------------------
|
Non-dyed
(Natural, boiling D.I. water sealing). |
| Class
2 |
------------------------
|
Dyed.
Shall not be applied to aluminum alloys with over 5.0%
copper, 7.0% silicon, or total alloying constituents
over 7.5%. When copper content is less than 4.6% and
for all suitable casting alloys be sure aluminum is
tempered (such as -T4 or T6) |
