corrosion midterm

Magnesium

Which of the following aircraft metals is the most chemically active and difficult to protect?

Lifting of paint film and white spots

What is the earliest visible sign of magnesium corrosion?

Several times the volume of the original metal

Magnesium corrosion products occupy:

White whiskers or snow-like mounds

In advanced stages, magnesium corrosion appears as:

Chromic acid + sulfuric acid

What tool is recommended for removing magnesium corrosion?

5–20 minutes

After applying chromic acid to corroded magnesium, how long should it remain

Chromic acid + sulfuric acid

Which solution is applied to corroded magnesium for chemical treatment?

Restoring protective paint

After treatment, the final step is:

They are more porous

Why are magnesium castings more vulnerable to corrosion than magnesium skins?

Contact the manufacturer for evaluation

If corrosion on a magnesium casting is extensive, what should be done?

Highly corrosion resistant

Titanium is naturally:

Steel wool

Which of the following is prohibited when cleaning titanium surfaces?

Sodium dichromate solution

After cleaning titanium, the surface should be treated with:

Galvanic or electrolytic corrosion

Corrosion between different metals in contact is called:

Saltwater

Which factor accelerates electrolytic corrosion between metals?

Two coats of zinc chromate or epoxy primer

For dissimilar joints not involving magnesium, what protection is applied?

Pressure-sensitive vinyl tape

For dissimilar joints involving magnesium, which is NOT always used if service temperature is above 250℉?

4

Corrosion damage is classified into how many categories?

The surface must still be cleaned, treated, and painted

“Negligible damage” means:

Replace the component

If corrosion damage exceeds repair limits, the only option is: