Mil-Spec Military Specifications for Corrosion Inhibitors
Military Specifications for CORROSION PREVENTIVES MIL-C-16173
CORROSION PREVENTIVES FOR FOUR TYPES OF CORROSION
WHAT IS CORROSION?
Corrosion is the wearing away or alteration of a metal or alloy either by
direct chemical attack or by electrochemical reaction. There are several
basic types, described below, which may occur singly or in combination.
TYPES OF CORROSION
This refers to the effect of corrosive agents present in the atmosphere,
such as oxygen, carbon dioxide, water vapor, and sulfur and chorine
compounds. The severity of this type of attack is directly related to the
amount of water vapor and sulfur and chlorine compounds present.
GALVANIC SERIES CHART
|ANODE (LEAST NOBLE)||Inconel (active)|
|Aluminum 1100||Copper-nickel alloys|
|Aluminum 2024-T4||Silver solder|
|Steel or Iron||Nickel (passive)|
|Cast Iron||Inconel (passive)|
|Chromium-iron (active)||Chromium-iron (passive)|
|Ni-Resist||Type 304 Stainless (passive)|
|Type 304 Stainless (active)||Type 316 Stainless (passive)|
|Type 316 Stainless (active)||Silver|
|Nickel (active)||CATHODE (MOST NOBLE)|
This type of corrosion is caused by the coupling of unlike metals in an electrolyte such as salt water, which results in an electrical transfer of particles from one metal to another. A reference to the Galvanic Series will show the relative positions of various metals and alloys. In general, depending upon the electrolyte, the further apart on the list, the greater the degree of attack with the less noble. Many so called specialized types of corrosion, such as contact corrosion, crevice corrosion, deposit attack, and impingement attack are forms of galvanic corrosion caused by localized galvanic cells of different potentials.
This chart shows a representative sample of metals and alloys arranged according to their relative potentials in a specified environment. Any metal will have a tendency to corrode when it is in contact with another metal in a lower position in the series in the presence of an electrolyte.
3) CONCENTRATION CELL CORROSION
This is sometimes called "deposit attack" or "crevice corrosion." It refers to the tendency of corrosion to build up more rapidly in the cracks and crevices of an assembly, such as in the internal construction of a vehicle or structural joints.
4) CORROSION FATIGUE
This is similar to stress corrosion except that the stresses are cyclic. Repeated loading and unloading usually causes accelerated rates of corrosion over those found in static stress corrosion, such as is encountered in the truck trailer leaf spring corrosion.
Mil C-16173D has been superseded by Mil PRF-16173E
Mil PRF-16173E exceeds all requirements of Mil C-16173
- Mil-Spec Corrosion Inhibitors
- Mil-Spec Coatings & Paint Related Materials
- NATO NSN Registered Products for Corrosion Control
- Mil-Spec Packaging for Corrosion Control
- Industrial Corrosion Control Coatings