NACE CP2 EXAM SCRIPT 2026 COMPLETE
QUESTIONS AND SOLUTIONS
GUARANTEED PASS
●● reduction.
Answer: gain of electrons, negative charged atoms (cathode)
●● forms of corrosion.
Answer: uniform, crevice, galvanic (dissimilar metals) if two metals
have to be couple then best to couple metals close together in the
galvanic series, pitting, intergranular, selective leaching (dezincification,
graphitization), velocity phenomena, environmental cracking (corrosion
fatigue, hydrogen embrittlement, SCC (Carbonates/bicarbonates)
●● High PH.
Answer: Low hydrogen, alkaline, easy polarization
●● Low PH.
Answer: high hydrogen, acidic, harder to polarize
●● High oxygen/High Hydrogen concentration.
Answer: harder to polarize, work at the cathode only, called cathodic
depolarizers.
,●● factors affecting corrosion.
Answer: A. anything that affects polarization. (temp. etc...)
B. concentration cells (oxygen, temp, etc.) In an oxygen concentration
cell, what is the anode? (i.e. the area with more or less oxygen?) In a
metal ion cell, which area is the anode (i.e. the area with the greater of
lower concentration)?
C. Anaerobic bacteria (MIC) Absence of oxygen, depolarizer
●● polarization.
Answer: a. corrosion current reduces with polarization
b. polarization increases with CP current applied
c. Occurs at surface of both anode and cathode.
●● shielding.
Answer: a. shorted casings
b. proximity of other structures
c. reinforced concrete
●● amphoteric materials.
Answer: corrode at low and high pH
●● on potential.
,Answer: native + polarization + IR drop
●● polarized potential (off).
Answer: native + polarization
●● kirchoff's laws.
Answer: a. voltage (series circuits)
b. current (parallel circuits)
●● faraday's law.
Answer: W=KIT
relates weight loss of metal in a corrosion cell with time and current
flow.
●● rate of corrosion.
Answer: directly proportional to current flow
●● cathodic protection limitations.
Answer: -shielding issues
-attenuation
-interference
-excessive current density
, -contact with other metals (shorts)
●● measurement methods.
Answer: true voltage reading
voltmeter reading
% error calculations
effect of voltmeter resistance
IR correction methods
●● test stations.
Answer: allow electrical connection to structure for potential
measurements and bonds.
Spans allow current and direction (IR drop).
inistall during construction
●● pH.
Answer: measure of acidity(hydrogen ion concentration)
high pH is alkaline
low pH is acid
pH is a log function therefore each increase in pH is a factor of 10.
●● RECTIFIER.
QUESTIONS AND SOLUTIONS
GUARANTEED PASS
●● reduction.
Answer: gain of electrons, negative charged atoms (cathode)
●● forms of corrosion.
Answer: uniform, crevice, galvanic (dissimilar metals) if two metals
have to be couple then best to couple metals close together in the
galvanic series, pitting, intergranular, selective leaching (dezincification,
graphitization), velocity phenomena, environmental cracking (corrosion
fatigue, hydrogen embrittlement, SCC (Carbonates/bicarbonates)
●● High PH.
Answer: Low hydrogen, alkaline, easy polarization
●● Low PH.
Answer: high hydrogen, acidic, harder to polarize
●● High oxygen/High Hydrogen concentration.
Answer: harder to polarize, work at the cathode only, called cathodic
depolarizers.
,●● factors affecting corrosion.
Answer: A. anything that affects polarization. (temp. etc...)
B. concentration cells (oxygen, temp, etc.) In an oxygen concentration
cell, what is the anode? (i.e. the area with more or less oxygen?) In a
metal ion cell, which area is the anode (i.e. the area with the greater of
lower concentration)?
C. Anaerobic bacteria (MIC) Absence of oxygen, depolarizer
●● polarization.
Answer: a. corrosion current reduces with polarization
b. polarization increases with CP current applied
c. Occurs at surface of both anode and cathode.
●● shielding.
Answer: a. shorted casings
b. proximity of other structures
c. reinforced concrete
●● amphoteric materials.
Answer: corrode at low and high pH
●● on potential.
,Answer: native + polarization + IR drop
●● polarized potential (off).
Answer: native + polarization
●● kirchoff's laws.
Answer: a. voltage (series circuits)
b. current (parallel circuits)
●● faraday's law.
Answer: W=KIT
relates weight loss of metal in a corrosion cell with time and current
flow.
●● rate of corrosion.
Answer: directly proportional to current flow
●● cathodic protection limitations.
Answer: -shielding issues
-attenuation
-interference
-excessive current density
, -contact with other metals (shorts)
●● measurement methods.
Answer: true voltage reading
voltmeter reading
% error calculations
effect of voltmeter resistance
IR correction methods
●● test stations.
Answer: allow electrical connection to structure for potential
measurements and bonds.
Spans allow current and direction (IR drop).
inistall during construction
●● pH.
Answer: measure of acidity(hydrogen ion concentration)
high pH is alkaline
low pH is acid
pH is a log function therefore each increase in pH is a factor of 10.
●● RECTIFIER.
