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ASTM G85 Annex A2 Cyclic
Acidified salt Fog Testing. For this variety of the Salt Spray Fog Test
the standard 5% sodium chloride solution is acidified to a ph of 2.8 to 3.0
by adding the proper amount of acetic acid. The temperature in the exposure
zone is maintained at 49°C +1.1 or -1.7°C (120°F +2 or -3°F).
This test is usually run
under what is referred to as 'wet bottom' conditions. This prevents the
inside of the box from drying out. Dry conditions would decrease the
corrosion rate.
However, for testing 2000
series aluminum alloys and some paint coatings a dry bottom test
is preferred.
The test is run as a series
of six hour cycles. These cycles consist of: 3⁄4 hr. spray, 2 hr.
dry-air purge, followed by 3 and 1/4 hr. soak at relative high humidity. To
obtain
complete specifications go to
ASTM International.
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