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Aircraft Corrosion
Aircraft Metals, Cleaning and Corrosion Control
Term | Definition |
---|---|
Stress Corrosion | The result of the combined effect of sustained tensile stresses and a corrosive environment. |
Surface Corrosion | Caused by either direct chemical or electrochemical attack. Appears as general roughening of the surface, with powdery deposits. |
Intergranular Corrosion | An corrosion attack along the grain boundaries of an alloy and commonly results from a lack of uniformity in the alloy structure; improper heat treatment. |
Dissimilar Metal Corrosion | A galvanic action occurs at the points or areas of contact where the insulation between the surfaces has broken down. |
Fretting Corrosion | Occurs when two mating surfaces, normally at rest, are subject to slight relative motion. |
Exfoliation Corrosion | Severe form of inter-granular corrosion. Lifting or flaking of the metal at the surface due to delamination of the grain boundaries caused by the pressure of corrosion residual product buildup. |
Pitting Corrosion | Advanced stages of surface corrosion. |
Fatigue Corrosion | Corrosion fatigue is fatigue in a corrosive environment. It is the mechanical degradation of a material under the joint action of corrosion and cyclic loading. |
Concentration Cell Corrosion | caused by a difference in concentration of some component in the electrolyte. (This difference leads to the formation of discrete cathode and anode regions). |
Filiform Corrosion | A random threadlike deterioration of a painted or lacquered metal caused by superficial corrosion of the base metal. |
Galvanic Corrosion | Also known as dissimilar metal corrosion. |
Active-Passive Cell Corrosion | Active-passive cells are often referred to as a type of concentration cell corrosion. However, the active-passive cell is actually two forms of corrosion working in conjunction. |
Hydrogen Embrittlement | hydrogen-induced cracking or severe loss of ductility caused by the presence of hydrogen in the metal. Hydrogen absorption may occur during electroplating, pickling, or other processes that favor the production of nascent or elemental hydrogen. |
Methyl Ethel Keytone | a solvent, used also to weld some plastics |
Aromatic Naphtha | a colorless, volatile petroleum distillate, usually an intermediate product between gasoline and benzine, used as a solvent, fuel, etc. |
Aliphatic Naphtha | aliphatic naphtha - the types suitable for use in organic coatings and as a cleaner for acrylic plastics. |
Emulsion Type Cleaner | An industrial cleaning process that uses an organic solvent as the main active agent. The solvent is usually a hydrocarbon of distilled petroleum dispersed in water used to clean loose dirt, grease, oxides, and carbon deposites |
Cathode | The cathode of a device is the terminal where current flows out. |
Electrolyte | A solution or molten substance that conducts electricity |
Electrochemical Corrosion Attack | occurs when electrons from atoms at the surface of the metal are transferred to a suitable electron acceptor or depolarizer (galvanic reaction). |
Chemical Corrosion Attack | the corrosion products are the result of direct combination between the reacting elements |
Anodizing | To coat (a metal, such as aluminium or magnesium) with a protective oxide film by electrolysis. An electrolytic treatment often performed by the manufacturing factory. |
Alodizing/Alodine | a dichromate conversion coating used with aluminum performed in the field. Clear, yellow, or gold in appearance, alodine's main purpose is to prepare aluminum for painting and prevent corrosion |
Ductility | Easily drawn into wire or hammered thin: ductile metals |
Ferrous | Metals related to or containing iron |
Nonferrous | pertaining to metals other than iron or steel |
Shear Load | load which tends to cause the sliding of one part of a member over another |
Tensile Load | A load tending to stretch the member. |
Bearing Strength | The measure of the ability of a material to sustain the applied load |
Yield Point | A measure of the amount of stress needed to permanently deform a material. When a material is stressed beyond its yield point or elastic limit, it will not return to its original shape and size when the stress is removed. |
Annealed | To subject (glass or metal) to a process of heating and slow cooling in order to toughen and reduce brittleness. Designated by the letter "O" To strengthen or harden. |
Normalized | To remove strains and reduce coarse crystalline structures in (metal), especially by heating and cooling. |
1000 Aluminum | Pure Aluminum |
2000 Aluminum | Copper is major alloy |
3000 Aluminum | Manganese is major alloy |
4000 Aluminum | Silicon is major alloy |
5000 Aluminum | Magnesium is major alloy |
6000 Aluminum | Magnesium and silicon are major alloys |
7000 Aluminum | Zinc in major alloy |
Toughness | Material resists tearing or breaking when it is bent or stretched. |
Brittleness | Opposite of plasticity. A material that cannot be visibly deformed and will shatter or break under load |
Elasticity | The ability of a material to deform under load and return to its original shape when the load is removed. |
Hardness | The ability to resist penetration. |
Malleability | The plasticity exhibited by a material under a pounding or a compression load. |
Fusibility | The ability to become liquid and adhere to other materials |
Thermal Conductivity | The ability to transfer temperature changes |
Alclad | product comprised of an aluminum alloy core having on one or both surfaces a metallurgically bonded aluminum or aluminum alloy coating that is anodic to the core and thus electrochemically protects the core against corrosion. |
Anode | The anode of a device is the terminal where current flows in from outside. Breaks down during the corrosion process |
Engine inlet, pitot and static lines, temperature probes | Prior to washing an aircraft, what openings should be closed or plugged to avoid water damage to components? |
Colloidal Cleaners | What is the type of cleaning agent consisting of a mixture of tiny particles of a substance dispersed and suspended in another substance. |
climate, foreign material, temperature, surface treatment, salt water, lubrication, stress | What factors will contribute to the corrosion on aircraft? |
Alcladding | The process of applying a thin coating relatively pure aluminum over the base aluminum alloy |
Visual | The most widely used nondestructive testing method for corrosion detection. |
Grains | The small crystalline regions of alloyed metals |
Rust (surface corrosion) | Most common type of corrosion |