MIL-DTL-83488D
and temperature to relieve any hydrogen embrittlement in the base metal. Nonsteel parts shall be
stripped by mechanical means or in a suitable chemical solution that does not result in degradation
of the base metal.
3.7
Adhesion. When tested in accordance with 4.4.2, the adhesion of the coating shall not
show separation from the base metal at the interface when examined at a minimum magnification
of approximately four-diameters. The interface between the aluminum and the base metal is the
surface of the base metal before coating. The formation of cracks in the deposit caused by
rupture of the base metal but does not result in flaking, peeling or blistering of the deposit shall
not be cause for rejection.
3.8
Corrosion resistance. When tested in accordance with 4.4.3, test samples shall show no
evidence of corrosion of the base metal after testing as specified in table 1. The appearance of
white corrosion products on the aluminum coating during the test period shall not be cause for
rejection.
Table 1. Salt Spray Test
Class
Test Period (hours)
Type I
Type II
1
504
672
2
336
504
3
168
336
3.9
Workmanship
3.9.1 Base metal. The base metal shall be free from defects that will be detrimental to the
appearance or the protective value of the coating.
3.9.2 Coating. The high purity aluminum coating shall be smooth, fine grained, adherent,
uniform in appearance, free from staining, pitting, and other defects. The coating shall show no
indication of contamination or improper operation of equipment used to produce the deposit, such
as excessively powdered or darkened coatings. Type II parts processed in accordance with
MIL-C-5541 requirements shall have a continuous, distinctly colored protective film ranging in
color from yellow and iridescent bronze through olive drab and brown.
3.10
Base metal integrity. When tested in accordance with 4.4.4, aluminum base metal parts,
after coating, shall have a Rockwell B hardness change of no more than 3 points. The hardness
after coating shall meet the minimum acceptable value for that alloy and temper.
5