Cleaning and Corrosion Control

Metal Finishing Aircraft parts are almost always provided with some type of surface finish by the manufacturer. The primary purpose of these finishes is to provide corrosion resistance; however, they may also be applied to improve wear resistance or to provide a suitable base for paint application. In most cases, the original finishes described in … Read more

Substances that cause corrosion of metals are called corrosive agents. The most common corrosive agents are acids, alkalies, and salts. The atmosphere and water, the two most common media for these agents, may also act as corrosive agents. Acids Moderately strong acids severely corrode most of the alloys used in airframes. The most destructive are … Read more

Many aircraft structures are made of metal, and the most insidious form of damage to those structures is corrosion. From the moment the metal is manufactured, it must be protected from the deleterious effects of the environment that surrounds it. This protection can be the introduction of certain elements into the base metal, creating a … Read more

When two dissimilar metals are placed in contact in the presence of moisture, galvanic corrosion can occur due to differences in their electrical potential. This condition is commonly referred to as dissimilar metal corrosion. The presence of an electrolyte, particularly salt water, accelerates the galvanic action. As a result, one of the metals undergoes oxidation … Read more

Preventive Maintenance Much has been done to improve the corrosion resistance of aircraft, such as improvements in materials, surface treatments, insulation, and modern protective finishes. All of these have been aimed at reducing the overall maintenance effort, as well as improving reliability. In spite of these improvements, corrosion and its control is a very real … Read more

Chemical Treatments Anodizing Anodizing is the most common surface treatment of nonclad aluminum alloy surfaces. It is typically done in specialized facilities in accordance with MIL-DTL-5541F or AMS-C-5541A. The aluminum alloy sheet or casting is the positive pole in an electrolytic bath in which chromic acid or other oxidizing agent produces an aluminum oxide film … Read more

Aircraft cleaning requires the proper selection and use of approved cleaning materials, solvents, and methods to ensure effective maintenance without damaging components. Various cleaning agents—such as solvents, emulsions, detergents, and mild abrasives—are used to remove contaminants including oil, grease, carbon deposits, and corrosion products. However, improper use of these materials can create safety hazards or … Read more

Corrosion of aircraft metals is a critical maintenance concern that directly affects structural integrity, safety, and service life. Different metals used in aircraft construction—such as steel, aluminum, magnesium, and titanium—exhibit unique corrosion characteristics and require specific inspection and treatment methods. Understanding how corrosion develops, how it appears on various materials, and how it can be … Read more

In general, any complete corrosion treatment involves cleaning and stripping of the corroded area, removing as much of the corrosion products as practicable, neutralizing any residual materials remaining in pits and crevices, restoring protective surface films, and applying temporary or permanent coatings or paint finishes. Repair of corrosion damage includes removal of all corrosion and … Read more