Corrosion Engineering MCQ
Corrosion Engineering MCQ is designed to help students, engineers, and competitive exam aspirants strengthen their understanding of corrosion mechanisms, prevention techniques, and material protection methods. This quiz covers essential topics such as electrochemical corrosion, galvanic corrosion, pitting, stress corrosion cracking, oxidation, corrosion inhibitors, cathodic and anodic protection, protective coatings, material selection, and corrosion testing methods. These multiple-choice questions are useful for Mechanical Engineering , Chemical Engineering, Metallurgical Engineering, Civil Engineering, GATE, SSC JE, RRB JE, PSU, and university examinations. Each question includes the correct answer and a detailed explanation to improve conceptual clarity and problem-solving skills. Regular practice with these Corrosion Engineering MCQs helps enhance technical knowledge, boosts confidence, and prepares candidates for academic exams, interviews, and professional certification tests. Start practicing now to master corrosion engineering concepts and improve your exam performance with high-quality, exam-oriented questions.
Q1. What is corrosion?
A. Destruction of metal by physical abrasion
B. Conversion of metal atoms into ions by chemical/electrochemical reaction
C. Deposition of impurities on metal
D. None of these
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Q2. Which type of corrosion is most difficult to detect?
A. Uniform corrosion
B. Pitting corrosion
C. Galvanic corrosion
D. Erosion corrosion
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Q3. Pilling-Bedworth Ratio (PBR) less than 1 indicates:
A. Protective oxide layer
B. Non-protective oxide layer that may crack
C. Crystal growth
D. Metal hardening
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Q4. Galvanic corrosion occurs when:
A. Two different metals are electrically connected in presence of an electrolyte
B. Metal is exposed to dry air
C. Only pure metal corrodes
D. No electrolyte involved
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Q5. What is the anodic reaction in corrosion?
A. Reduction of oxygen
B. Oxidation of metal atoms to ions
C. Reduction of hydrogen
D. Oxidation of water
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Q6. Cathodic protection involves:
A. Making entire structure cathode to prevent corrosion
B. Increasing anodic sites
C. Increasing corrosion
D. Chemical cleaning
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Q7. Which metal corrodes preferentially and protects other metals when connected?
A. Copper
B. Zinc
C. Iron
D. Gold
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Q8. Crevice corrosion is caused due to:
A. Oxygen concentration differences in confined spaces
B. Mechanical wear
C. Surface contamination
D. Temperature difference
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Q9. Passivation refers to:
A. Increase in corrosion rate
B. Formation of a protective oxide film that slows corrosion
C. Complete immunity to corrosion
D. None
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Q10. Which of following is a common corrosion inhibitor?
A. Chromates
B. Chlorides
C. Nitrates
D. Sulfates
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Q11. The rate of corrosion depends on:
A. Surface area, temperature, environment
B. Only surface color
C. Only humidity
D. None
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Q12. Corrosion resulting in uniform thinning over entire surface is:
A. Pitting
B. General corrosion
C. Galvanic corrosion
D. Stress corrosion
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Q13. What is the effect of increasing oxygen concentration on corrosion?
A. Typically increases corrosion rate
B. Decreases corrosion rate
C. No effect
D. Depends on humidity only
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Q14. Electrochemical corrosion requires:
A. Anode, cathode, electrolyte, conductive path
B. Only acid
C. Only moisture
D. Only metal
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Q15. Stress corrosion cracking occurs due to:
A. Mechanical stress and corrosive environment
B. High temperature only
C. High pressure only
D. Mechanical wear
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Q16. Which of the following is a method to prevent corrosion?
A. Painting and coating
B. Heating
C. Cooling
D. Mixing metals
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Q17. Rust is primarily:
A. Iron oxide
B. Copper oxide
C. Zinc oxide
D. Aluminum oxide
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Q18. Sacrificial anode cathodic protection mainly uses which metal?
A. Iron
B. Zinc
C. Copper
D. Lead
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Q19. Passivating metals include:
A. Aluminum, chromium, stainless steel
B. Iron, copper, lead
C. Gold, silver
D. Zinc, tin
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Q20. Which process measures corrosion rate?
A. Weight loss method
B. Color test
C. Sound measurement
D. Thermal test
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Q21. Galvanic series is:
A. A list of metals ranked by their corrosion potential
B. List of metals by price
C. List of metals by density
D. None
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Q22. Corrosion inhibitors work by:
A. Reducing anodic or cathodic reactions
B. Increasing metal surface
C. Reducing temperature
D. Increasing moisture
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Q23. Pitting corrosion is:
A. Uniform corrosion
B. Localized corrosion producing holes
C. Galvanic corrosion
D. Crevice corrosion
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Q24. Stress corrosion cracking primarily affects:
A. Brittle materials
B. Ductile metals under tensile stress and corrosive environment
C. Polymers
D. Glass only
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Q25. Which layer protects stainless steel from corrosion?
A. Chromium oxide
B. Iron oxide
C. Copper oxide
D. Zinc oxide
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Q26. Cathodic protection is commonly used on:
A. Ships hulls, pipelines, storage tanks
B. Concrete structures
C. Glass walls
D. Wooden furniture
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Q27. Impressed current cathodic protection requires:
A. External power source
B. Natural conditions
C. Sacrificial anodes
D. Paint coating
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Q28. Corrosion potential difference between two metals causes:
A. Galvanic corrosion
B. Uniform corrosion
C. No corrosion
D. Heat transfer
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Q29. Which corrosion type involves microbial activity?
A. Biodegradation
B. Microbial influenced corrosion (MIC)
C. Uniform corrosion
D. Galvanic corrosion
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Q30. Stress corrosion cracks often initiate at:
A. Surface imperfections or notches
B. Central bulk metal
C. Pure crystals only
D. Polymers
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Q31. Metal passivation creates:
A. Active Olympic rings
B. Protective oxide layer
C. Metalic glow
D. None
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Q32. Cyclic polarization curves are used to study:
A. Corrosion rates and passivity
B. Heat transfer
C. Mechanical strength
D. Electrical conductivity
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Q33. Which condition accelerates corrosion?
A. High humidity and temperature
B. Low humidity
C. Low temperature
D. Dry air
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Q34. Role of oxygen in aqueous corrosion is:
A. Anodic reactant
B. Cathodic reactant
C. Inert gas
D. None
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Q35. Electrochemical corrosion cell requires:
A. Electrode, electrolyte, external circuit
B. Only metal
C. Only air
D. Only soil
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Q36. Corrosion scale formation can:
A. Increase corrosion
B. Protect underlying metal
C. None
D. Reduce density
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Q37. Which is an effective rust prevention method?
A. Regular painting and coating
B. Exposure to air
C. Salt water exposure
D. None
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Q38. Electrochemical corrosion is reversible?
A. Yes
B. No
C. Sometimes
D. Only in metals
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Q40. Which is commonly used to measure corrosion rate?
A. Weight loss method
B. Current measurement
C. Visual inspection
D. Magnetic testing
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