MIL-DTL-83488D
4.3.1.3 Aluminum or copper parts. In accordance with AMS-QQ-A-250/4 or equivalent, for
2000 series aluminum or copper parts, or 7075-T6 in accordance with AMS-QQ-A-250/12 or
equivalent, for 7000-series aluminum parts, use metal strips approximately 1 inch by 4 inches by
0.040 inch made of 2024-T81.
4.3.2 Thickness test sample. In accordance with AMS 6350 or equivalent, use metal strips
approximately 1 inch by 4 inches by 0.040 inch made of 4130 steel. Test samples shall be used
only when the base metal is other than a ferrous alloy.
4.3.3 Corrosion test samples. In accordance with AMS 6350 or equivalent, use panels at least
3 inches wide by 6 inches long by 0.040 inch made of 4130 steel for corrosion tests.
4.4
Methods of inspection
4.4.1 Thickness. In accordance with 4.2.1.1, test samples shall have the thickness determined
by eddy current test, beta backscatter test, micrometer measurements, microscopic test, or
magnetic tests. The magnetic test is applicable only to ferrous alloy substrates. The beta
backscatter test shall be made in accordance with ASTM B567. The microscopic test shall be
made in accordance with ASTM B487. The magnetic test shall be made in accordance with
ASTM B499. For verification of other test methods, the microscopic test shall be used. If the
thickness of the coating on a nonferrous alloy part cannot suitably be measured with any of these
test devices, test specimens in accordance with 4.3.2 may be used. Due to coating wraparound
the coating thickness on the test specimens (4.3.2) is thicker than on the production parts. To
compensate for the wraparound effect the thickness on the production parts is determined by
dividing the thickness measured on the test specimens by 1.6.
4.4.2 Adhesion. In accordance with 4.2.1.1, test samples shall have adhesion determined by
methods 4.4.2.1 or 4.4.2.2. Test samples for individual production parts shall be in accordance
the 4.4.2.3. The eddy current test for conductivity measures shall be made in accordance with
ASTM E1004.
4.4.2.1 Nonadhesion. Scrape the surface of the coated article (4.3.1) to expose the base metal
and examine at a minimum of four-diameter magnification for evidence of nonadhesion. Any
evidence of nonadhesion from the base metal shall be cause for rejection.
4.4.2.2 Strip rupture. Clamp the coated test strip (4.3.1) in a vise and bend back and forth until
strip rupture occurs. If the edge of the ruptured coating can be peeled back or if separation
between the coating and the base metal can be seen at the point of rupture when examined at
four-diameter magnification adhesion it shall be cause for rejection.
4.4.2.3 As-applied coating. For individual production parts only, burnish the as-applied
coating with glass bead until a shiny, uniform appearance is obtained. The peening nozzle shall be
held at 6 to 8 inches above the part and the nozzle shall slowly be passed completely over the
part. Peening residue shall be removed with dry nitrogen gas or oil-free filtered air. Removal of
the coating from the base metal shall be cause for rejection.
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