The following is a list of military plating and coating specifications:
Anodize (Chromic and Sulfuric), MIL-A-8625F: Conventional Types I, IB, and II anodic coatings are intended to improve surface corrosion protection under severe conditions or as a base for paint systems. Coatings can be colored with a large variety of dyes and pigments. Class 1 is nondyed; Class 2 dyed.
Anodize Coating Thickness |
Type |
Thickness |
I |
0.00002″ - 0.0007″ |
IB |
IC |
IIB |
II |
0.00072″ - 0.00102″ |
Type I and IB coatings should be used on fatigue critical components (due to thinness of coating). Type I, unless otherwise specified, should not be applied to aluminum alloys with over 5% copper or 7% silicon or total alloying constituents over 7.5%. Type IC is a mineral or mixed mineral/organic acid that anodizes. It provides a non-chromate alternative for Type I and IB coatings where corrosion resistance, paint adhesion, and fatigue resistance are required. Type IIB is a thin sulfuric anodizing coating used as non-chromate alternatives for Type I and IB coatings where corrosion resistance, paint adhesion, and fatigue resistance are required.
Black Oxide Coating, MIL-C-13924C: A uniform, mostly decorative, black coating for ferrous metals used to decrease light reflection. Provides very limited corrosion protection under mild corrosion conditions. Black oxide coatings should normally be given a supplementary treatment. Typically used for moving parts that cannot tolerate the dimensional change of a more corrosion resistant finish. Use alkaline oxidizing for wrought iron, cast and malleable irons, plain carbon, low alloy steel, and corrosion resistant steel alloys. Alkaline-chromite oxidizing may be used on certain corrosion resistant steel alloys tempered at less than 900°F. Salt oxidizing is suitable for corrosion resistant steel alloys that are tempered at 900°F or higher.
Cadmium, QQ-P-416F: Cadmium plating is required to be smooth, adherent, uniform in appearance, free from blisters, pits, nodules, burning, and other defects when examined visually without magnification. Unless otherwise specified in the engineering drawing or procurement documentation, the use of brightening agents in the plating solution to modify luster is prohibited on components with a specified heat treatment of 180 ksi minimum tensile strength (or 40 Rc) and higher. Either a bright (not caused by brightening agents) or dull luster is acceptable. Baking on Types II and III needs to be completed prior to the application of supplementary coatings.
Cadmium Plating Thickness |
Class |
Min. Thickness |
1 |
0.0005″ |
2 |
0.0003″ |
3 |
0.0002″ |
Type I is to be used for plating. Types II and III require supplementary chromate and phosphate treatment respectively. Chromate treatment required for type II may be colored iridescent bronze to brown including olive drab, yellow, and forest green. Type II is recommended for corrosion resistance. Type III is used as a paint base and is excellent for plating stainless steels that are to be used in conjunction with aluminum to prevent galvanic corrosion. For Types II and III the minimum cadmium thickness requirement must be met after the supplementary treatment.
Lubrication, Solid Film MIL-L-46010D: The Military Plating Specification establishes requirements for three types of heat cured solid film lubricants that are intended to reduce wear and prevent galling, corrosion, and seizure of metals. Solid Film lubricants are intended for use on aluminum, copper, steel, stainless steel, titanium, and chromium, and nickel bearing surfaces.
Types I, II, and III have a thicknesses of 0.008-0.013 mm. No single reading less than 0.005 mm or greater than 0.018 mm is acceptable.
Lubrication Curing Temperatures and Endurance Life |
Type |
Curing Temperature |
Endurance Life |
I |
150 ± 15°C |
250 minutes |
II |
204 ± 15°C |
450 minutes |
III |
150 ± 15°C for two hours, or
204 ± 15°C for one hour |
450 minutes |
Type III is a low volatile organic compound (VOC) content lubricant. Color 1 has a natural product color and Color 2 has a black color.
Nickel, QQ-N-290A: There is a nickel finish for almost any need. Nickel can be deposited soft, harddull, or bright depending on the process used and conditions employed in plating. Thus, hardness can range from 150-500 Vickers. Nickel can be similar to stainless steel in color, or can be a dull gray (almost white) color. Corrosion resistance is a function of thickness. Nickel has a low coefficient of thermal expansion.
All steel parts having a tensile strength of 220,000 or greater should not be a nickel plated without specific approval of the procuring agency.
Class 1 is used for corrosion protection. Plating needs to be applied over an underplating of copper or yellow brass on zinc and zinc based alloys. At no time should the copper underplating be substituted for any part of the specified nickel thickness. Class 2 is used in engineering applications.
Nickel Plating Thickness |
Grade |
Thickness |
A |
0.0016″ |
B |
0.0012″ |
C |
0.001″ |
D |
0.0008″ |
E |
0.0006″ |
F |
0.0004″ |
G |
0.002″ |
Phosphate Coating: Heavy, DOD-P-16232-F: The primary differences between Type M and Type Z coatings are that Type M is used as a heavy manganese phosphate coating for corrosion and wear resistance and Type Z is used as a zinc phosphate coating.
Type M has a thickness from 0.0002-0.0004″ and Type Z, 0.0002-0.0006″. Class 1, for both types, has a supplementary preservative treatment or coating as specified; Class 2 has a supplementary treatment with lubricating oil; and no supplementary treatment is required for Class 3. For Type M, Class 4 is chemically converted (may be dyed to color as specified) with no supplementary coating or supplementary coating as specified. For Type Z, Class 4 is the same as Class 3.
This coating is for medium and low alloy steels. The coatings range from gray to black in color. The “heavy” phosphate coatings covered by this specification are intended as a base for holding/retaining supplemental coatings which provide the major portion of the corrosion resistance. “Light” phosphate coatings used for a paint base are covered by other specifications. Heavy zinc phosphate coatings may
be used when paint and supplemental oil coatings are required on various parts or assemblies.
Zinc, ASTM-B633: This specification covers requirements for electrodeposited zinc coatings applied to iron or steel articles to protect them from corrosion. It does not cover zinc-coated wire or sheets. Type I will be as plated; Type II will have colored chromate conversion coatings; Type III will have colorless chromate conversion coatings; and Type IV will have phosphate conversion coatings.
High strength steels (tensile strength over 1700 Mpa) are not to be electroplated.
Stress relief: All parts with ultimate tensile strength 1000 Mpa and above baked at minimum 190°C for three hours or more before cleaning and plating.
Hydrogen embrittlement relief: All electroplated parts 1200 Mpa or higher shall be baked at 190°C for three hours or more within four hours after electroplating.
Corrosion Resistance Requirements |
Type |
Test Period (Hours) |
II |
96 |
III |
12 |