Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
48 Cards in this Set
- Front
- Back
BLANK is the electrochemical deterioration of a material or its properties due to its chemical reaction with the surrounding environment? |
Corrosion |
|
The smallest unit of an element, made
up of a positively charged nucleus surrounded by a system of negatively charged electrons? |
ATOM
|
|
What is a negatively charged subatomic
particle? |
Electron
|
|
What is a atom or group of atoms or molecules which has acquired a net electric charge by gaining(negative ion) or losing (positive ion) electrons. |
Ion |
|
A liquid (usually water) solution |
Electrolyte |
|
Most alloys are made up entirely of small crystalline regions called?
|
Grains
|
|
What make electrical contact in the presence of an electrolyte, the rate at which corrosion occurs depends on the difference in their activities, what is their positions? |
Dissimilar Metals |
|
The rate of corrosion also depends on the size of the parts in contact. If the surface area of the corroding metal BLANK is smaller than the surface area of the less active metal BLANK, corrosion will be rapid and severe. |
(the anode), (the cathode) |
|
Dirt, salt, acidic stack gases, and |
Electrolyte |
|
In the same way that metals can corrode when exposed to different concentrations of oxygen in an electrolyte, corrosion will also occur if the BLANK on the surface varies from one location to another. |
Concentration of the Electrolyte |
|
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. |
an oxygen concentration cell or differential aeration cell |
|
Higher BLANK environments tend to produce more rapid corrosion due to accelerated chemical reactions and, in humid environments, higher concentration of water vapor in the air. |
Temperature |
|
BLANK consists of bacteria, molds,fungi, and other living organisms (some microscopic) that can grow on damp surfaces.Once they are well established, the area tends to remain damp, increasing the possibility of corrosion. |
BIOLOGICAL ORGANISMS |
|
Many alloys used in aircraft construction are sensitive to a form of corrosion known as BLANK cracking. |
Stress Corrosion |
|
BLANK 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 |
Uniform Surface Corrosion |
|
What corrosion occurs when different metals are in contact with each other and an electrolyte, such as sea water? |
Galvanic corrosion |
|
BLANK is an attack on the grain |
Intergranular corrosion |
|
BLANK is a form of extremely localized attack that results in holes in the metal. |
Pitting corrosion |
|
BLANK 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? |
Exfoliation |
|
BLANK 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? |
Crevice corrosion |
|
BLANK 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? |
Filiform corrosion |
|
BLANK 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? |
Erosion corrosion |
|
BLANK is the intergranular or transgranular cracking of a metal caused by the combined effects of |
Stress corrosion |
|
BLANK 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? |
Corrosion fatigue |
|
BLANK 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? |
Fretting corrosion |
|
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. |
HOT CORROSION |
|
Are the most widely used materials for aircraft construction. In addition to its uses in aircraft? |
Aluminum and aluminum alloys
|
|
Some aluminum parts are protected with an electrochemically applied |
Anodized
|
|
Are the lightest structural metals used for aircraft and missile |
Magnesium alloys |
|
Surface pitting, intergranular, exfoliation, stress corrosion and fatigue cracking, and fretting. White to gray powder? |
Aluminum Alloy |
|
Highly susceptible to pitting White, powdery, snowlike mounds,and white spots on surface? |
Magnesium Alloy |
|
Surface oxidation and pitting;surface and intergranular corrosion Reddish-brown oxide (rust). |
Carbon & Low Alloy Steel(4000-8000 series) |
|
Crevice corrosion; some pitting in marine environments; corrosion cracking; intergranular corrosion (300 series); surface corrosion (400series)Rough surface; sometimes a red, brown, or black stain. |
Stainless Steels(300-400 series) |
|
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 above700° F (370° C). |
Titanium Alloy |
|
Uniform surface corrosion From white powdery deposit to brown or black mottling of the surface. |
Cadmium (used as a protective platingfor steel) |
|
Pitting (promotes rusting of steel where pits occur in plate)No visible corrosion products; blistering of plating due to rusting and lifting. |
Chromium (plate) |
|
Generally has good corrosion resistant qualities; susceptible to pitting in sea water Green powdery deposit. |
Nickel-base Alloy (Inconel, Monel) |
|
Pitting and flaking of surface platingNickel does not corrode, but promotes corrosion of aluminum base metal where pits occur in the plating. |
Electroless Nickel(used as a plating |
|
Surface and intergranular corrosion Blue or blue-green powdery deposit. |
Copper-base Alloy,Brass, Bronze |
|
Will tarnish in presence of sulfur Brown to black film. |
Silver |
|
Highly corrosion resistant Deposits cause darkening of reflective surfaces. |
Gold |
|
Subject to whisker growth Whisker-like deposits. |
Tin |
|
are used to manufacture many aircraft components and massive structures and assemblies in aircraft ground supportequipment, such as missile gantries, silo crib structures, frames and bodies of trailers and vans, and lesser structural parts such as brackets, racks, and panels. |
STEEL or Ferrous (iron) alloys |
|
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. |
Stainless steels, or corrosion resistant steels (as they are more properly described) |
|
UV light, moisture, solvents Discoloration, cracking. |
Acrylic |
|
Dirt, UV light, solvent, moisture Cracking, peeling. |
Adhesive |
|
Extreme heat Discoloration, cracking |
Ceramic |
|
Dry rot, mildew Discoloration, tears, dust |
Cloth |