Module 8 Corrosion and Failure Analysis Objective Four

Question 1

Corrosion inhibitor

Answer 1

a substance that retards corrosion when low concentrations are added to an environment

Question 2

Absorbed Films

Answer 2

usually have a cationic (+ ion) end to a long organic molecule. The positive end of the molecule is attracted to the metal surface and the long organic portion keeps electrolyte away from the metal

Question 3

Passivating Inhibitors

Answer 3

create a protective chromate or phosphate film that forms a barrier to corrosion.

Question 4

Anodic Passivating Inhibitors

Answer 4

cheaper, and can function without oxygen. Needs a decent amount to cover the surface and stop pitting

Question 5

Cathodic Precipates

Answer 5

inorganic inhibitors form precipitates on cathodic areas, which slow down the cathode reaction.

Question 6

Neutralization of acids

Answer 6

decreases the corrosion rate

Question 7

Cathodic Protection

Answer 7

supplies electrons to oppose the loss of free flowing electrons through the metal

Question 8

Sacrificial anodes

Answer 8

anodes are made of reactive metals that have a more negative reduction potential than the material they’re protecting.

Question 9

Impressed current cathodic protection

Answer 9

used where large currents are required and power from electrical lines are available.
DC flows from one or more anodes into the structure requiring protection