This set of Corrosion Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Environments – Soil and Aerospace”.
1. The corrosivity of soils varies over a wide range because of the variety of composition.
a) True
b) False
View Answer
Explanation: The corrosivity of a particular solution depends on its composition. So, the corrosivity of soils varies over a wide range because of the variety of composition.
2. Which of the factors that affect the corrosiveness of soils?
a) Moisture
b) Acidity
c) Oxygen
d) Moisture, oxygen, acidity and stray currents
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Explanation: The factors that affect the corrosiveness of soils are moisture, oxygen, acidity, alkalinity, the permeability of air and water, stray currents, and biological organisms.
3. Which of the following is a good measure of corrosivity?
a) Thermal conduction
b) Electrical resistance
c) Thermal resistance
d) Mechanical properties
View Answer
Explanation: Electrical resistance is a good measure of corrosivity of a corrosive solution. Higher electrical resistance lowers the corrosivity of a solution. Dry soils are generally not very corrosive due to high electrical resistance.
4. Which of the following type of corrosion is/are dominant due to backfills such as stones, cinders, wood, and metal?
a) Crevice corrosion
b) Pitting corrosion
c) Crevice and pitting corrosion
d) Neither crevice nor pitting corrosion
View Answer
Explanation: Crevice and pitting corrosion are the types of corrosion that dominate due to backfill such as stones, cinders, wood, and metal. Because these foreign particles result in the formation of crevices.
5. Which of the following is/are true regarding underground structures?
a) Ordinary carbon steels and cast irons are commonly used
b) Organic coatings can be used
c) Cathodic protection is applied to protect it from corrosion
d) Usually made of carbon steel and cast irons with or without organic coatings and supported by a cathodic protection system
View Answer
Explanation: Underground structures are usually made up of ordinary carbon steels and cast irons with or without organic coatings. These structures are also supported by a cathodic protection system to minimize corrosion.
6. Which of the following type of corrosion is pre-dominate in underground corrosion?
a) Aerobic corrosion
b) Anaerobic corrosion
c) Aerobic and anaerobic corrosion
d) Neither aerobic nor anaerobic corrosion
View Answer
Explanation: The anaerobic type of attack is pre-dominate in underground corrosion. It is due to the non-availability of oxygen as it decreases with an increase in depth.
7. Which of the following areas of aircrafts face severe corrosion problems?
a) Fuel tank due to oxidizers and fuel
b) High-temperature corrosion in blast nozzles
c) The outer structure of the plane due to vacuum
d) Fuel tank due to oxidizers and fuel, high-temperature corrosion in blast nozzles
View Answer
Explanation: Fuel tank due to oxidizers and fuel and high-temperature corrosion in blast nozzles are the two areas that aerospace face severe corrosion problems. Whereas the hard vacuum of space does not cause corrosion.
8. Which of the following materials is/are used for blast nozzles in aerospace?
a) Aluminum oxide and cemented tungsten carbide
b) Aluminum oxide cemented tungsten carbide and boron carbide
c) Cemented tungsten carbide only
d) Aluminum oxide and boron carbide
View Answer
Explanation: Aluminum oxide, cemented tungsten carbide, and boron carbide is the materials that are used for blast nozzles in aerospace. These materials are also known as refractory materials.
9. Which of the following is/are the prime considerations in space vehicles and aircraft?
a) High strength-weight ratios for materials and high ratios of payload to the vehicle’s weight
b) High strength-weight ratios for materials only
c) High ratios of payload to vehicles weight only
d) Neither high strength-weight ratios for materials nor high ratios of payload to the vehicle’s weight
View Answer
Explanation: High strength-weight ratio for materials and high ratios of payload to vehicle weight are the two prime considerations in space vehicles and aircraft.
10. Rusting of high-strength steel due to resident water can cause stress-corrosion and hydrogen embrittlement.
a) False
b) True
View Answer
Explanation: Rusting of high-strength steel due to resident water can cause stress-corrosion and hydrogen embrittlement. Hydrogen charging of steel during electroplating can cause a brittle fracture.
11. Which of the following is/are the primary materials regarding the construction of aircraft?
a) Aluminum
b) Magnesium and titanium
c) Aluminum, magnesium, titanium, and iron
d) Titanium and magnesium
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Explanation: Aluminum, magnesium, titanium, and iron and their alloys are the primary materials regarding the construction of aircraft. These are selected based on a high strength-weight ratio for materials and high ratios of payload to vehicle weight.
12. Which of the following corrosion protective systems is/are included in aircraft industries?
a) Anodizing, cladding and conversion coatings
b) Anodizing and cathodic protection
c) Conversion coatings and anodizing
d) Cathodic protection only
View Answer
Explanation: Anodizing, cladding, and conversion coatings are the corrosive protective systems used in aircraft industries. Whereas cathodic protection cannot be used in the aircraft industry due to non-conductive electrolytes.
Sanfoundry Global Education & Learning Series – Corrosion Engineering.
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