Corrosion and Materials Selection MCQs 2026

Cathodic protection makes structure

1. Aanode intentionally✓
2. Binsulated electrically always without current✓
3. Calways hotter✓
4. Dcathode of electrochemical cell✓

Stress corrosion cracking needs

1. Aonly compression in dry air✓
2. Bonly lubricant oil alone✓
3. Conly polishing✓
4. Dtensile stress, susceptible alloy and corrosive environment✓

Galvanic corrosion requires

1. Aelectrochemical potential difference and electrolyte✓
2. Bonly mechanical wear without moisture✓
3. Conly high temperature without electrolyte always✓
4. Donly UV light✓

Pitting corrosion is

1. Auniform thickness loss only✓
2. Bonly intergranular always✓
3. Clocalized attack forming cavities✓
4. Donly erosion without electrochemistry✓

Passivation on stainless steel is

1. Athick zinc coating only always✓
2. Bthin protective oxide film✓
3. Cplastic liner only✓
4. Dgraphite layer only✓