Aviation and Aerospace Expertise
AVIATION & AEROSPACE INDUSTRY CORROSION PROTECTION
Corrosion is a perennial problem in the aircraft industry, and preventing corrosion is a critical factor in maintaining the integrity and safety of an aircraft vehicle. Left undetected and untreated, aircraft corrosion can quickly lead to potentially catastrophic vehicle failure.
CAUSES OF CORROSION
Corrosion occurs when metal is exposed to oxygen and moisture. Corrosive chemicals or dissimilar metals can also initiate the corrosion process. Surface corrosion frequently occurs where metal is exposed or paint has worn thin. Stress corrosion is a common problem for aircraft under tensile stress in corrosive environments. Corrosion risks increase with aircraft age or exposure to extreme moisture and harsh environments.
Good corrosion preventive maintenance and early treatment are crucial strategies for protecting aircraft from corrosion failure. Keeping a vehicle clean with corrosion inhibiting washes and storage methods helps protect aircraft from corrosion attack during regular use and storage. Sometimes rust removal may be needed before applying additional corrosion inhibitors, such as VpCI® primers and coatings, to an aircraft. With Cortec® Vapor phase Corrosion Inhibitors (VpCIs) it is possible to slow the attack of corrosion on aircraft from multiple angles.
Corrosion on aircraft surfaces can be indicated by roughening, etching, pitting, or blistering of the paint or plating, as well as the presence of powdery deposits. Surface corrosion of the filiform type looks like the presence of worms under the paint.
DISSIMILAR METAL CORROSION
Electrochemical corrosion can occur when dissimilar metals come in contact with each other and create a galvanic action. This can cause pitting damage that is difficult to detect because it often arises in unseen areas of an aircraft.
Flaking metal may be an indication of intergranular corrosion. This is usually instigated by lack of uniformity in the metal stemming back to the manufacturing process. Intergranular corrosion can be difficult to detect.
The combination of a corrosive environment and tensile stress can result in stress corrosion cracking. This is common and often occurs in metal systems such as landing gear.
The slight rubbing of two mated surfaces can produce pitting and fine debris. Often the debris is trapped in tight locations. The problem worsens in the presence of moisture.
1 Source: FAA AC 8083-30 Chapter 6: Aircraft Cleaning and Corrosion Control