MIL-PRF-87260B(USAF)
4.5.19 Corrosion and adhesion test.
One 4-inch by 3-inch specimen cut such that the 4-inch dimension is in the direction of material
rise shall be exposed in contact with 7075 aluminum alloy per SAE AMS-QQ-A-250 or ASTM
B209 for 14 days at 75 ±5°F (room temperature) and 95 ±5 percent relative humidity. Color
photographs shall be taken of all specimens and plates both before and after exposure.
4.5.19.1 Roughness test.
Three sets of metallic plates shall be used having a surface finish of 5-15 microinches obtained
by lapping. The roughness shall be determined by a profilometer or equivalent instrument. The
roughness reading is the arithmetical average of the deviations in the surface expressed in
microinches measured normal to the surface. For these tests the surface finish should be
prepared per 4.5.19.1.1.
4.5.19.1.1 Surface finish.
A surface finish of 5-15 microinches measured perpendicular to the lay at a roughness-width
cutoff rating of 0.030 inch and a maximum roughness-width rating of 0.015 inch. One set shall
be clamped together with the baffle material specimen such that the baffle material is
compressed from 4 to 3 inches in thickness in contact with the polished surfaces. This set
along with one set of extra plates (controls) shall then be exposed for 14 days at room
temperature and 95 ±5 percent relative humidity in a sealed container or humidity cabinet. In
addition, the third set of plates shall be used to run a comparison test on the vendor's basic blue
polyether foam having the same porosity as the conductive material. Test specimens should be
oriented such that the metal plates are vertical in order to minimize moisture condensation and
pooling on the plate surfaces. At the termination of the test, there shall be no adhesion of the
baffle material to the metal plates, nor any evidence of pitting, erosion, corrosion, or bad
discoloration as a result of the material contact, as determined by the following procedures.
The basis for the comparison shall be the exposed set of control plates.
a. The surfaces of the plates that were in contact with the material shall be inspected for
such things as discoloration, deposits, and pitting. If any of these conditions exists, the surface
of the plates shall be washed in precipitation naphtha. Deposits determined as urethane
materials or elements, which can be removed by this process, shall be construed as adhesion.
b. If any other marks remain on the surface of the plates after being washed in
precipitation naphtha as specified in 4.5.19.1.1a, the surfaces shall be lightly polished with a
nonabrasive cloth buff. Any pits or eroded marks remaining after this process shall be
construed to be corrosion. Discoloration or staining (marks that do not physically affect the
surface of the plates and that easily wash or buff off) shall not be considered detrimental.
4.5.19.2 Test report.
All test data, including the photographs, shall be included in the test report. In addition, the test
plates shall also be submitted to the qualifying activity.
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