Aircraft Corrosion Quiz

What are the two general forms of corrosion mentioned in the text?

• Direct chemical corrosion and electro-chemical corrosion

• Pitting and crevice corrosion

• Stress corrosion and fretting

• Microbiological fuel corrosion and surface defects

Answer explanation

The correct answer is 'Direct chemical corrosion and electro-chemical corrosion' as these are the two general forms of corrosion. Other options refer to specific types or causes of corrosion, not general forms.

Which type of corrosion is more likely to occur in aircraft?

• Crevice corrosion

• Electro-chemical corrosion

• Pitting corrosion

• Direct chemical corrosion

Answer explanation

Electro-chemical corrosion is prevalent in aircraft due to the presence of moisture and dissimilar metals, leading to galvanic reactions. This type of corrosion can cause significant damage if not properly managed.

What is a common preventative measure for electro-chemical corrosion in aircraft?

• Applying heat treatment

• Using sacrificial anodes like zinc

• Increasing the use of steel components

• Using copper rivets

Answer explanation

Using sacrificial anodes like zinc is a common preventative measure for electro-chemical corrosion in aircraft. These anodes corrode instead of the aircraft's metal components, protecting them from damage.

Which of the following is NOT a condition necessary for corrosion to occur?

• Presence of an anode and a cathode

• High temperature environment

• A metallic connector between anode and cathode

• An electrolyte such as water

Answer explanation

A high temperature environment is not necessary for corrosion to occur. Corrosion requires an anode, a cathode, a metallic connector, and an electrolyte like water, but not necessarily high temperatures.

What is the most common type of corrosion to affect airplanes?

• Crevice corrosion

• Stress corrosion cracking

• Pitting corrosion

• Microbiological fuel corrosion

Answer explanation

Crevice corrosion is the most common type affecting airplanes due to the presence of tight spaces where moisture and contaminants can accumulate, leading to localized corrosion. This makes it a significant concern in aviation maintenance.

Which material is least likely to corrode among common aircraft materials?

• Magnesium alloys

• 2000 series aluminium alloys

• Graphite composites

• Brass and bronze alloys

Answer explanation

Graphite composites are highly resistant to corrosion compared to metals like magnesium alloys, aluminium alloys, and brass/bronze, which are more prone to corrosion due to environmental factors.

What is a common cause of stress corrosion cracking (SCC) in metals?

• Exposure to high temperatures

• Presence of microbiological organisms

• Contact with saline solutions

• High residual stress in parts of a metal object

Answer explanation

High residual stress in metal parts can lead to stress corrosion cracking (SCC) as it makes the material more susceptible to environmental factors, causing cracks to form and propagate under stress.

Which of the following is a method to reduce metal to composite corrosion?

• Excluding moisture from the structure

• Applying heat treatment

• Increasing the use of magnesium alloys

• Using aluminium rivets

Answer explanation

Excluding moisture from the structure is crucial in reducing metal to composite corrosion, as moisture can accelerate corrosion processes. The other options do not directly address moisture control.

What is a common effect of fretting in aircraft components?

• Increased ductility

• Reduced fatigue strength

• Enhanced electrical conductivity

• Improved corrosion resistance

Answer explanation

Fretting in aircraft components leads to surface wear and micro-cracking, which reduces fatigue strength. This makes the components more susceptible to failure under cyclic loading, compromising their structural integrity.

Which of the following is a suitable metal for rivets to prevent rapid corrosion?

• Aluminium

• Titanium

• Magnesium

• Copper

Answer explanation

Titanium is highly resistant to corrosion due to its protective oxide layer, making it a suitable choice for rivets in environments prone to rapid corrosion. Other metals like aluminum and copper are less effective in this regard.