One great threat to structural integrity of support
chemical or electrochemical process. In the direct
equipment is metal corrosion. Support equipment may
chemical attack, the reaction that occurs is similar to
be used in a variety of climatic and atmospheric
acid applied to bare metal. The most familiar type of
conditions, which range from the hot, dry desert to the
corrosion reaction is between metal and water and is
hot, humid Tropics to the cold, Arctic regions. In
electrochemical.
addition, the equipment is most often used in a
salt-filled atmosphere, such as coastal shore bases, on
In the electrochemical attack, metals of different
islands, and especially on aircraft carriers. Shipboard
electrical potential are involved, and they need not be in
and coastal support equipments are subjected to the
direct contact. The electrically charged ions of one
effect of sea winds that can carry 10 to 100 pounds of
metal are exchanged with charged ions of the opposite
salt per cubic mile of air. These difficult environmental
metal through a conductor. This conductor is the
conditions vary the speed and intensity of metal
chemical agent and is known as electrolyte. It could be
corrosion.
moisture, dirt, collection of fluids, debris, or anything
that will allow the flow of electrical ions.
SUPPORT EQUIPMENT CORROSION
There are many factors that effect the type, speed,
CONTROL
and cause of corrosion. In the electrochemical attack, it
Corrosion reduces the strength of materials and the
is a more serious factor in wet, humid climates. Also,
strength of joints between parts. Most equipment is
the salt of seawater and sea air is one of the greatest
designed with an extra margin of strength for safety.
single accelerating causes. In hot or extremely cold
Corrosion can weaken the structure, thereby reducing
climates, the corrosion process is increased. In cold
or eliminating this safety factor. Replacement or
climates, the cause is from melting snow or ice. In
reinforcement operations are costly, time-consuming,
contrast, the hot, dry inland air vastly reduces the
and reduce usage of the equipment. Severe corrosion
corrosion process.
can cause failure of parts or systems. Such
Corrosion can be controlled by maintaining a dry
malfunctions can cause an important item of equipment
environment through the use of suitable moisture
to become inoperative during very critical demands.
barriers or drying agents. This is what is meant by the
You must know and be able to apply the common
term preservation.
types of corrosion prevention and moisture-protecting
CORROSION PUBLICATIONS
materials. To accomplish this, you must be familiar
with the types and causes of corrosion, types and uses
The AS rating covers a vast amount of different
of cleaning materials, materials and procedures for
types and models of support equipment; therefore, it
preservation and depreservation, and the means for the
only makes sense that you would use a variety of
detection of corrosion.
publications in the corrosion prevention and treatment
The problem of protection for support equipment
process.
during storage and shipment is threefold: (1) prevention
of corrosion of the metal parts; (2) control of
Support Equipment Corrosion Control Manual
elimination of physical damage to the support
Ground Support Equipment Cleaning and
equipment during handling. Of these three, corrosion of
Corrosion Control, NAVAIR 17-1-125, is the current
metals is the most difficult to control.
technical manual to be used in the prevention,
detection, and repair of corrosion on ground support
Under corrosive conditions, metals tend to lose
equipment. This publication takes precedence over any
their metallic characteristics because they are trying to
and all maintenance instruction manuals (MIMs) and
revert to their natural state. In other words, corrosion
service instruction manuals (SIMs) at both the
reverses the refining processes that produce the metals
organizational- and intermediate-level maintenance
from their original ores. The tendency to corrode differs
activities for methods of prevention, detection, and
greatly between various metals. For example,
repair of corrosion. You still follow the maintenance
magnesium alloys are very difficult to protect
and service manuals in conjunction with matters not
compared to the relatively good corrosion-resistant
pertaining to corrosion control.
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