Topic 8 - Deterioration of Materials

Question 1

How do the various materials degrade/corrode?

Answer 1

Deterioration is generally the result of electro-chemical reactions. Where electrons are given up by metals in an oxidation reaction and these electrons are consumed in a reduction reaction.

Question 2

How does corrosion occur?

Answer 2

Charge transfer between an ionic and electronic conductor.

Question 3

Which metals are most likely to corrode?

Answer 3

Metals are ranked according to their corrosiveness in standard emf and galvanic series. Ex. Aluminum alloys, iron/steel, cadmium, zinc, and magnesium.

Question 4

What environmental parameters affect corrosion rate?

Answer 4

Temperature and solution composition affect corrosion rates.

Question 5

How do we prevent or control corrosion?

Answer 5

Materials selection, reducing the temperature, applying physical barriers, adding inhibitors, and cathodic protection.