Podcast
Questions and Answers
What happens to the strength of the metal affected by exfoliation corrosion?
What happens to the strength of the metal affected by exfoliation corrosion?
- It becomes more flexible
- It remains the same
- It greatly decreases (correct)
- It increases
What is the recommended remedy when exfoliation corrosion is evident on the metal surface?
What is the recommended remedy when exfoliation corrosion is evident on the metal surface?
- Polishing the surface
- Heating the metal
- Complete removal of the affected sections (correct)
- Applying a protective coating
Where do microbiological growths in aircraft fuel tanks primarily live and feed?
Where do microbiological growths in aircraft fuel tanks primarily live and feed?
- Inside the fuel lines
- In the air
- On the metal tank structure
- In the water collected in the tanks (correct)
What type of organic bodies are microbes found in aircraft fuel tanks?
What type of organic bodies are microbes found in aircraft fuel tanks?
What do microbes in aircraft fuel tanks produce that promotes corrosion?
What do microbes in aircraft fuel tanks produce that promotes corrosion?
What flight conditions contribute to water condensation in aircraft fuel tanks?
What flight conditions contribute to water condensation in aircraft fuel tanks?
What type of corrosion is described as an extreme case of intergranular corrosion?
What type of corrosion is described as an extreme case of intergranular corrosion?
In fretting corrosion, what destroys the protective film that develops on surfaces?
In fretting corrosion, what destroys the protective film that develops on surfaces?
What visual indication can appear around rivets in skin if fretting corrosion is occurring?
What visual indication can appear around rivets in skin if fretting corrosion is occurring?
Which type of materials are most susceptible to exfoliation corrosion?
Which type of materials are most susceptible to exfoliation corrosion?
Why must rivets showing signs of fretting corrosion be replaced as soon as possible?
Why must rivets showing signs of fretting corrosion be replaced as soon as possible?
What characteristic makes exfoliation corrosion distinct from other types of corrosion?
What characteristic makes exfoliation corrosion distinct from other types of corrosion?
What happens if prompt treatment is not provided when white, puffy areas are discovered on a structure?
What happens if prompt treatment is not provided when white, puffy areas are discovered on a structure?
In what type of environment does the natural oxide-carbonate film on magnesium alloys not provide sufficient corrosion protection?
In what type of environment does the natural oxide-carbonate film on magnesium alloys not provide sufficient corrosion protection?
What is a consequence of titanium absorbing gases at high temperatures from the surrounding air?
What is a consequence of titanium absorbing gases at high temperatures from the surrounding air?
What effect can chlorides and some chlorinated solvents have on certain titanium alloys?
What effect can chlorides and some chlorinated solvents have on certain titanium alloys?
What does the oxide film that forms on titanium surfaces provide?
What does the oxide film that forms on titanium surfaces provide?
Why is electrical insulation necessary between titanium and other metals?
Why is electrical insulation necessary between titanium and other metals?
What is a common application of pure nickel?
What is a common application of pure nickel?
How does the stress corrosion resistance of stainless steel alloys change with increasing nickel content?
How does the stress corrosion resistance of stainless steel alloys change with increasing nickel content?
In what areas are nickel-based alloys commonly used?
In what areas are nickel-based alloys commonly used?
What is a common application of copper and copper-based alloys in avionics systems?
What is a common application of copper and copper-based alloys in avionics systems?
What is a common sign of copper corrosion on a part?
What is a common sign of copper corrosion on a part?
What can lead to flaking of the nickel coating?
What can lead to flaking of the nickel coating?
Why is tarnish removal critical on gold components?
Why is tarnish removal critical on gold components?
What is the result of gold corrosion over silver or copper in thin layers?
What is the result of gold corrosion over silver or copper in thin layers?
What is 'Purple plague' in the context of gold-aluminium compounds?
What is 'Purple plague' in the context of gold-aluminium compounds?
Which metal offers the best combination of solderability and corrosion resistance?
Which metal offers the best combination of solderability and corrosion resistance?
What tends to grow 'whiskers' on tin-plated wire and other plated applications?
What tends to grow 'whiskers' on tin-plated wire and other plated applications?
Why is corrosion accelerated over less noble metals when gold plated over them in thin layers?
Why is corrosion accelerated over less noble metals when gold plated over them in thin layers?
What determines whether a power header or a hand beading tool is used to accomplish beading of a tube?
What determines whether a power header or a hand beading tool is used to accomplish beading of a tube?
What is the purpose of the inner liner in a flexible hose used in aircraft fluid systems?
What is the purpose of the inner liner in a flexible hose used in aircraft fluid systems?
Why does the inner liner of a flexible hose need to be chemically compatible with the material being carried?
Why does the inner liner of a flexible hose need to be chemically compatible with the material being carried?
What is the main function of an outer cover in the construction of a flexible hose?
What is the main function of an outer cover in the construction of a flexible hose?
What is essential for the inner liner of a flexible hose in terms of porosity?
What is essential for the inner liner of a flexible hose in terms of porosity?
Why is flexibility throughout an entire range of operating temperatures essential for the inner liner of a flexible hose?
Why is flexibility throughout an entire range of operating temperatures essential for the inner liner of a flexible hose?
What is the angle of the external flare in AN fittings?
What is the angle of the external flare in AN fittings?
What material are AN steel fittings colored as for identification purposes?
What material are AN steel fittings colored as for identification purposes?
What type of tube is used with flareless fittings?
What type of tube is used with flareless fittings?
Which metal base alloys are flared-tube fittings made of?
Which metal base alloys are flared-tube fittings made of?
What color are AN aluminium fittings for identification?
What color are AN aluminium fittings for identification?
How many parts does a flared-tube fitting consist of?
How many parts does a flared-tube fitting consist of?
Which synthetic compound is best suited for carrying phosphate ester-base hydraulic fluids?
Which synthetic compound is best suited for carrying phosphate ester-base hydraulic fluids?
Which synthetic rubber is more suitable for carrying petroleum products than neoprene?
Which synthetic rubber is more suitable for carrying petroleum products than neoprene?
Which synthetic compound breaks down if used with petroleum products?
Which synthetic compound breaks down if used with petroleum products?
Which synthetic compound has an extremely broad operating temperature range and offers minimum resistance to fluid flow?
Which synthetic compound has an extremely broad operating temperature range and offers minimum resistance to fluid flow?
Which synthetic rubber is used with petroleum-based fluids and is abrasion resistant?
Which synthetic rubber is used with petroleum-based fluids and is abrasion resistant?
Which compound has a unique chemical structure that leads to less volumetric expansion than rubber?
Which compound has a unique chemical structure that leads to less volumetric expansion than rubber?
What is the purpose of O-rings in some applications of banjo fittings?
What is the purpose of O-rings in some applications of banjo fittings?
What feature allows the banjo to rotate before the bolt is torqued during installation?
What feature allows the banjo to rotate before the bolt is torqued during installation?
In which fluid systems are quick-disconnect couplings commonly used?
In which fluid systems are quick-disconnect couplings commonly used?
What is the primary function of the sliding collar in some quick-disconnect couplings?
What is the primary function of the sliding collar in some quick-disconnect couplings?
What type of lines are typically joined using rubber hoses and screw-type hose clamps?
What type of lines are typically joined using rubber hoses and screw-type hose clamps?
What is the advantage of having a built-in shutoff valve in quick-disconnect couplings?
What is the advantage of having a built-in shutoff valve in quick-disconnect couplings?
What is the purpose of the outer cover in a hose?
What is the purpose of the outer cover in a hose?
What information can be found on the lay line of an aircraft flexible hose's outer cover?
What information can be found on the lay line of an aircraft flexible hose's outer cover?
Why are reinforcement layers essential in hoses?
Why are reinforcement layers essential in hoses?
What is generally marked on the outer cover of an aircraft flexible hose?
What is generally marked on the outer cover of an aircraft flexible hose?
How can one determine if a hose is twisted during installation?
How can one determine if a hose is twisted during installation?
What materials are commonly used for reinforcement layers in hoses?
What materials are commonly used for reinforcement layers in hoses?
Study Notes
Corrosion and Metal Strength
- Exfoliation corrosion reduces the strength of metals, leading to structural integrity issues.
- Recommended remedies include removing the affected areas and applying protective coatings.
Microbiological Growth in Aircraft Fuel Tanks
- Microbial growths primarily thrive in water present in aircraft fuel tanks, feeding on hydrocarbons.
- Microbes often consist of bacteria and fungi that derive energy from fuel components.
- These microorganisms produce acids and other byproducts that accelerate corrosion.
Conditions Leading to Corrosion
- Water condensation due to temperature changes and humidity contributes to corrosion in aircraft fuel tanks.
- Exfoliation corrosion is an extreme form of intergranular corrosion, affecting the metal's grain boundaries.
Fretting Corrosion
- In fretting corrosion, mechanical movements destroy protective films on metal surfaces.
- Visual signs of fretting corrosion include white, powdery deposits around rivets.
Material Susceptibility
- Aluminum and its alloys are highly susceptible to exfoliation corrosion.
- Rivets showing fretting corrosion must be replaced promptly to prevent further deterioration.
Unique Characteristics of Corrosion
- Distinct characteristics of exfoliation corrosion include the formation of layers that can flake off.
- White, puffy areas, if unaddressed, can lead to severe material failure over time.
Corrosion Protection in Magnesium Alloys
- The natural oxide-carbonate film on magnesium alloys fails to protect in highly corrosive environments.
Titanium Behavior
- Titanium's absorption of gases at high temperatures can lead to embrittlement.
- Chlorides and chlorinated solvents can negatively impact certain titanium alloys.
Titanium Oxide Film
- The oxide film on titanium surfaces serves as a protective barrier against corrosion.
- Electrical insulation between titanium and other metals prevents galvanic corrosion.
Nickel and Alloys
- Pure nickel is commonly used in various applications, offering good corrosion resistance.
- Increased nickel content in stainless steel alloys enhances resistance to stress corrosion cracking.
Applications of Copper and Alloys
- Copper and copper-based alloys are often used in avionics systems for electrical connections.
- Signs of copper corrosion include greenish-blue staining or patina on components.
Nickel Coating Issues
- Flaking of nickel coatings can occur due to improper surface preparation or adhesion issues.
- Removal of tarnish on gold components is crucial to maintain electrical conductivity and prevent corrosion.
Gold-Aluminium Compounds
- 'Purple plague' refers to the formation of a brittle layer between gold and aluminum alloys that can lead to failure.
- Gold plating provides excellent solderability and corrosion resistance, but thin layers can exacerbate issues with whiskers.
Flexible Hose Construction
- The inner liner in flexible hoses ensures fluid compatibility and prevents leaks.
- It is crucial for the inner liner to withstand various operating temperatures without compromising flexibility.
Fitting Types and Identification
- AN fittings have a 37-degree external flare angle.
- Identification colors for AN fittings: steel fittings typically have a cadmium plating, while aluminum fittings are colored blue.
Hose Reinforcement and Indicators
- Reinforcement layers in hoses prevent bulging and rupture under pressure.
- The lay line on a hose's outer cover contains essential information, including specifications and operating limits.
Additional Hose Aspects
- Quick-disconnect couplings are widely used in hydraulic systems for rapid maintenance and safety.
- A built-in shutoff valve in quick-disconnect couplings prevents fluid leakage during disconnection.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Learn about fretting corrosion in materials and hardware from the training materials for CASA Part 66. Understand how surfaces erode when they fit tightly together but can move relative to each other, leading to the destruction of the protective film due to rubbing action.
