Free NACE Cathodic Protection Principles Questions and Answers

Question 1

What is the primary purpose of cathodic protection (CP)?

Accepted Answer

To control corrosion by making the metal a cathode

Answer

To increase the electrical resistance of the metal

Answer

To provide a decorative finish to the metal surface

Answer

To insulate the metal from all environments

Question 2

Which of the following is a type of cathodic protection system?

Accepted Answer

Both galvanic anode and impressed current systems

Answer

Only galvanic anode systems

Answer

Only impressed current systems

Answer

Neither galvanic nor impressed current systems

Question 3

What is the typical material used for sacrificial anodes in seawater environments?

Accepted Answer

Zinc or aluminum alloys

Answer

Copper

Answer

Stainless steel

Answer

Carbon steel

Question 4

What is the criterion for effective cathodic protection of steel in soil?

Accepted Answer

A negative potential of -850 mV vs. CSE

Answer

A positive potential of +850 mV vs. CSE

Answer

Zero voltage potential

Answer

A resistance of 1000 ohms

Question 5

What is the purpose of a reference electrode in CP systems?

Accepted Answer

To measure the electrical potential of the protected structure

Answer

To supply current to the system

Answer

To replace sacrificial anodes

Answer

To increase soil resistivity

Question 6

Which NACE standard covers the control of external corrosion on underground or submerged metallic piping systems?

Accepted Answer

NACE SP0169

Answer

NACE SP0177

Answer

NACE TM0102

Answer

NACE RP0188

Question 7

What is a common anode material for impressed current CP systems?

Accepted Answer

Mixed Metal Oxide (MMO) anodes

Answer

Magnesium

Answer

Cast iron

Answer

Copper

Question 8

What is the 100 mV polarization criterion in cathodic protection?

Accepted Answer

A 100 mV negative shift from the native potential

Answer

A 100 mV increase in soil resistivity

Answer

A 100 mV positive shift from the native potential

Answer

A 100 mV reduction in current output

Question 9

What is stray current corrosion and how can CP mitigate it?

Accepted Answer

Corrosion caused by external DC sources, mitigated by proper CP current distribution

Answer

Corrosion caused by bacteria, mitigated with biocides

Answer

Corrosion due to alternating current, mitigated with insulators

Answer

Corrosion from high temperatures, mitigated with cooling systems