01 March 2005
15 July 2008
5-1. PURPOSE. The materials, equipment, and
techniques described in this chapter are intended to
assist the avionic technician at the Organizational/Unit
Metal portions of brushes should be wrapped
and Intermediate Maintenance Activity (IMA) in treating
with masking tape prior to applying conversion
exposed metal surfaces on avionic equipment. Chemical
coating material in order to protect against
conversion coatings, protective coatings (paints),
encapsulants, and sealants are discussed.
Chemical conversion treatment is an extremely
Chemical conversion solutions can become
important part of the corrosion control process. Properly
contaminated if in contact with glass containers,
applied chemical treatments impart considerable
ferrous metals (other than 300 series stainless
corrosion resistance to the basic metal and greatly
steels), or copper alloys. Stainless steel,
improve the adhesion of subsequently applied paints.
polyethylene, and polypropylene containers
Refer to Volume II for information on applying chemical
should be used. Discard all contaminated
Chemical film materials are strong oxidizers
and a fire hazard when in contact with organic
materials such as paint thinners. Do not store or
mix surface treatment materials in containers
previously containing flammable products. Rags
contaminated with chemical film materials
Silver nitrate, A-A-59282, is corrosive and
should be treated as hazardous materials and
toxic to eyes, skin, and respiratory tract. Avoid
disposed of accordingly.
all contact. Skin and eye protection required.
Use only in a well ventilated area.
5-2.1. ALUMINUM ALLOYS. The application of
c h e m i c a l conversion material is covered by
5-2.3. METAL DETERMINATION. Magnesium may
MIL-C-5541. For treatment of aluminum alloys, use
be distinguished from aluminum by a spot test with
chemical conversion material, MIL-DTL-81706. Class 1A
silver nitrate solution.
provides superior corrosion protection. However, Class 3
a. Dissolve a few crystals (approximately 1/4
required, such as mounting of antennas. The bulk
teaspoon) of Silver Nitrate, A-A-59282 (Volume IV or
chemical conversion materials for aluminum are
premixed and require no further adjustment prior to use.
(2 tablespoons) of distilled water.
T h e Touch-N-Prep (TNP) pen, Alodine 1132
MIL-DTL-81706 applicators qualify for both Class 1A
b. Select or make a clean bare metal spot and
and Class 3 and are ideal for touching up small surface
place a drop of solution on it. If the area turns black, the
areas. Use of the TNP pens does not require rinsing or
material is magnesium. Aluminum shows no reaction.
wiping off following application, thereby minimizing
hazardous waste generation. Empty pens can be
c. In the event Silver Nitrate, A-A-59282 is not
returned to manufacturer for disposal.
available, use Silver Nitrate Solution (Volume IV or V,
5-2.2. MAGNESIUM ALLOYS. Magnesium alloys shall
be treated with chemical conversion material,
d. Place one drop of the solution on the bare metal.
AMS-M-3171, Type VI. Premixed material is available
If the area turns black, the metal is magnesium.
in the magnesium treatment kit (see Volume IV or V).