Term
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Definition
| ______ is the electrochemical deterioration of a material or its properties due to its chemical reaction with the surrounding environment? |
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Term
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Definition
The smallest unit of an element, made
up of a positively charged nucleus surrounded by a system of negatively charged electrons? |
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Term
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Definition
A negatively charged subatomic
particle? |
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Term
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Definition
An atom or group of atoms or molecules
which has acquired a net electric charge by gaining(negative ion) or losing (positive ion) electrons. |
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Term
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Definition
A liquid (usually water) solution
containing ions. Sea water is an electrolyte: an aqueous(water-based) solution whose major components are
sodium and chloride ions. |
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Term
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Definition
| Most alloys are made up entirely of small crystalline regions called? |
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Term
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Definition
What make electrical contact in the presence of an electrolyte, the rate at which corrosion occurs depends
on the difference in their activities, that is, their positions? |
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Term
| (the anode), (the cathode) |
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Definition
The rate of corrosion also depends on the size of the parts in contact. If the surface area of the corroding
metal______is smaller than the surface area of the less active metal ______, corrosion will be rapid and severe. |
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Term
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Definition
Dirt, salt, acidic stack gases, and
engine exhaust gases can dissolve on wet surfaces,increasing the electrical conductivity of the ______,
thereby increasing the rate of corrosion. |
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Term
| concentration of the electrolyte |
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Definition
| In the same way that metals can corrode when exposed to different concentrations of oxygen in an electrolyte, corrosion will also occur if the ______ on the surface varies from one location to another. |
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Term
| an oxygen concentration cell or differential aeration cell |
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Definition
| When some of the electrolyte on a metal surface is partially confined (such)as between faying surfaces or in a deep crevice), metal in this confined area corrodes more rapidly than other metal surfaces of the same part outside this area. This type of corrosion is called? |
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Term
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Definition
Higher _______ environments tend to produce more rapid corrosion due to accelerated chemical reactions and, in humid environments, higher concentration of water vapor in
the air. |
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Term
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Definition
Bacterias, molds,fungi, and other living organisms (some microscopic)
can grow on damp surfaces.Once they are well established, the area tends to remain damp, increasing the possibility of corrosion. |
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Term
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Definition
| Many alloys used in aircraft construction are sensitive to a form of corrosion known as ______ cracking. |
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Term
| Uniform surface corrosion |
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Definition
| ______ is probably the most common type of corrosion. It results from a direct chemical attack on a metal surface that proceeds uniformly over the entire exposed surface. |
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Term
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Definition
| _______ occurs when different metals are in contact with each other and an electrolyte, such as sea water. It is usually recognizable by the presence of a buildup of corrosion deposits at the joint between the metals. |
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Term
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Definition
| ______ is a form of extremely localized attack that results in holes in the metal. |
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Term
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Definition
______ is an attack on the grain
boundaries of the metal. A highly magnified cross section of any commercial alloy and granular structure of the metal. |
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Term
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Definition
______ is an advanced form of intergranular corrosion where the surface grains of a metal are lifted up by the force of expanding corrosion
products occurring at the grain boundaries? |
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Term
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Definition
| ______ is one of the most familiar types of corrosion. Field experience shows that this type of corrosion may occur in any crevice where a stagnant solution has pooled? |
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Term
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Definition
______ is a form of crevice corrosion which occurs on metal surfaces having a thin (~4 mils) organic protective
coating. It is recognized by its characteristic worm like trace of corrosion products beneath the coating? |
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Term
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Definition
_______ is the increase in the rate of attack on a metal due to the
action of a corrosive fluid against the metal surface. Generally the movement is rapid, and wear or abrasion occurs with the corrosion.
Characterized by grooves, gullies, waves, rounded holes and/or valleys in the metal surface? |
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Term
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Definition
______is the intergranular or transgranular cracking of a metal caused by the combined effects of
constant tensile stress (internal or applied) and corrosion. Internal or residual stresses may be produced by welding,cold working, forming, and heat treatment operations during the manufacture of a part? |
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Term
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Definition
| _____is the cracking of metals caused by the combined effects of cyclic stress and corrosion. No metal is immune to reduction in its resistance to cyclic stress if the metal is in a corrosive environment? |
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Term
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Definition
| ______occurs at contact areas between materials under load subject to repeated vibration. The relative motion needed to produce fretting is extremely small (sometimes as little as 10-8 cm? |
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Term
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Definition
Also called high temperature oxidation. Corrosion in the absence of
water can occur at high temperatures? such as those found in turbine engine combustors, turbine sections,
and afterburners. |
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Term
| Aluminum and aluminum alloys |
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Definition
| Are the most widely used materials for aircraft construction. In addition to its uses in aircraft? structure, |
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Term
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Definition
Some aluminum parts are protected with an electrochemically applied
oxide coating called? |
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Term
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Definition
Are the lightest structural metals used for aircraft and missile
airframes? |
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Term
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Definition
| Surface pitting, intergranular, exfoliation, stress corrosion and fatigue cracking, and fretting. White to gray powder? |
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Term
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Definition
| Highly susceptible to pitting White, powdery, snowlike mounds,and white spots on surface? |
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Term
| Carbon & Low Alloy Steel(4000-8000 series) |
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Definition
Surface oxidation and pitting;
surface and intergranular corrosion Reddish-brown oxide (rust). |
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Term
Stainless Steels
(300-400 series) |
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Definition
Crevice corrosion; some pitting in marine environments; corrosion cracking; intergranular corrosion (300 series); surface corrosion (400
series)Rough surface; sometimes a red, brown, or black stain. |
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Term
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Definition
Highly corrosion resistant; extended or repeated contact with chlorinated solvents may result in degradation of the metal's structural properties.
Cadmium plated tools can cause embrittlement. No visible corrosion products at low temperature. Colored surface oxides develop above
700° F (370° C). |
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Term
Cadmium (used as a protective plating
for steel) |
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Definition
Uniform surface corrosion From white powdery deposit to brown or black
mottling of the surface. |
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Term
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Definition
| Pitting (promotes rusting of steel where pits occur in plate)No visible corrosion products; blistering of plating due to rusting and lifting. |
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Term
| Nickel-base Alloy (Inconel, Monel) |
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Definition
| Generally has good corrosion resistant qualities; susceptible to pitting in sea water Green powdery deposit. |
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Term
| Electroless Nickel(used as a plating) |
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Definition
Pitting and flaking of surface plating
Nickel does not corrode, but promotes corrosion of aluminum base metal where pits occur in the plating. |
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Term
| Copper-base Alloy,Brass, Bronze |
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Definition
| Surface and intergranular corrosion Blue or blue-green powdery deposit. |
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Term
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Definition
| Will tarnish in presence of sulfur Brown to black film. |
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Term
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Definition
| Highly corrosion resistant Deposits cause darkening of reflective surfaces. |
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Term
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Definition
| Subject to whisker growth Whisker-like deposits. |
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Term
| STEEL or Ferrous (iron) alloys |
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Definition
are used to manufacture many aircraft components and massive structures and assemblies in aircraft ground support
equipment, such as missile gantries, silo crib structures, frames and bodies of trailers and vans, and lesser structural parts such as brackets, racks, and panels. |
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Term
| Stainless steels, or corrosion resistant steels (as they are more properly described) |
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Definition
| are alloys of iron containing large amounts of chromium and nickel. Are used for gears, bearings, and high strength bolts, and for mountings, racks, brackets, and hardware in avionic systems. |
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Term
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Definition
| UV light, moisture, solvents Discoloration, cracking. |
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Term
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Definition
| Dirt, UV light, solvent, moisture Cracking, peeling. |
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Term
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Definition
| Extreme heat Discoloration, cracking |
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Term
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Definition
| Dry rot, mildew Discoloration, tears, dust |
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