171. Which of the following is an example of a galvanic corrosion couple?
a) Aluminum and copper
b) Copper and stainless steel
c) Stainless steel and zinc
d) Zinc and aluminum
View Answer
Correct answer: b) Copper and stainless steel
Explanation: Galvanic corrosion occurs when two dissimilar metals are in contact in the presence of an electrolyte, forming a galvanic cell. An example is the coupling of copper and stainless steel, where the less noble metal (copper) corrodes.
172. Which corrosion prevention method involves controlling the pH of the environment to reduce corrosion rates?
a) Galvanization
b) Cathodic protection
c) Passivation
d) pH adjustment
View Answer
Correct answer: d) pH adjustment
Explanation: Adjusting the pH of the environment can help reduce corrosion rates by controlling the acidity or alkalinity, which can influence the electrochemical reactions involved in corrosion.
173. Which corrosion prevention method involves the use of alloying elements to enhance the corrosion resistance of a metal?
a) Galvanization
b) Alloying
c) Passivation
d) Coating
View Answer
Correct answer: b) Alloying
Explanation: Alloying refers to the addition of specific elements to a metal to form alloys with enhanced corrosion resistance properties, such as adding chromium to iron to produce stainless steel.
174. Which of the following is an example of intergranular corrosion?
a) Uniform corrosion on a metal surface
b) Pitting corrosion on a metal surface
c) Corrosion at the grain boundaries of a metal
d) Stress corrosion cracking of a metal
View Answer
Correct answer: c) Corrosion at the grain boundaries of a metal
Explanation: Intergranular corrosion occurs at the grain boundaries of a metal, often due to the depletion of protective elements or impurities in the vicinity of grain boundaries.
175. Which corrosion prevention method involves the removal of oxygen from the environment to inhibit corrosion?
a) Cathodic protection
b) Passivation
c) Oxygen scavenging
d) pH adjustment
View Answer
Correct answer: c) Oxygen scavenging
Explanation: Oxygen scavenging involves the use of chemical agents or methods to remove or reduce the presence of oxygen in the environment, inhibiting the corrosion process.
176. Which of the following metals is prone to galvanic corrosion when coupled with stainless steel?
a) Aluminum
b) Copper
c) Zinc
d) Carbon steel
View Answer
Correct answer: d) Carbon steel
Explanation: When carbon steel is coupled with stainless steel in the presence of an electrolyte, galvanic corrosion occurs, as stainless steel is more noble and protected compared to carbon steel.
177. Which corrosion prevention method involves the use of organic or inorganic coatings to protect the metal surface?
a) Barrier protection
b) Cathodic protection
c) Passivation
d) Inhibitor protection
View Answer
Correct answer: a) Barrier protection
Explanation: Barrier protection involves the application of organic or inorganic coatings, such as paints or epoxy coatings, to physically separate the metal surface from the corrosive environment.
178. Which of the following is an example of an active corrosion protection method?
a) Barrier protection
b) Cathodic protection
c) Passivation
d) Coating
View Answer
Correct answer: b) Cathodic protection
Explanation: Cathodic protection is an active corrosion protection method that actively controls the corrosion process through the use of sacrificial anodes or impressed current systemsto protect the metal from corrosion.
179. Which corrosion prevention method involves the use of chemical compounds that react with the metal surface to form a protective layer?
a) Galvanization
b) Cathodic protection
c) Passivation
d) Chemical conversion coating
View Answer
Correct answer: d) Chemical conversion coating
Explanation: Chemical conversion coatings involve the use of chemical compounds that react with the metal surface to form a protective layer, inhibiting corrosion.
180. Which of the following is an example of a corrosion inhibitor?
a) Paint
b) Epoxy coating
c) Grease
d) Zinc sacrificial anode
View Answer
Correct answer: c) Grease
Explanation: Grease can act as a corrosion inhibitor by forming a protective barrier between the metal surface and the corrosive environment, preventing direct contact and corrosion initiation.
