Corrosion and Materials Selection MCQs 2026

Galvanic corrosion requires

1. A electrochemical potential difference and electrolyte ✓
2. B only mechanical wear without moisture ✓
3. C only high temperature without electrolyte always ✓
4. D only UV light ✓

Passivation on stainless steel is

1. A thick zinc coating only always ✓
2. B thin protective oxide film ✓
3. C plastic liner only ✓
4. D graphite layer only ✓

Pitting corrosion is

1. A uniform thickness loss only ✓
2. B only intergranular always ✓
3. C localized attack forming cavities ✓
4. D only erosion without electrochemistry ✓

Cathodic protection makes structure

1. A anode intentionally ✓
2. B insulated electrically always without current ✓
3. C always hotter ✓
4. D cathode of electrochemical cell ✓

Stress corrosion cracking needs

1. A only compression in dry air ✓
2. B only lubricant oil alone ✓
3. C only polishing ✓
4. D tensile stress, susceptible alloy and corrosive environment ✓