NACE CP2 EXAM EXAM SCRIPT 2026
COMPLETE QUESTIONS AND CORRECT
ANSWERS
◉ 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. Answer: - positive to anode
-negative to structure
- AC suppy
-AC circuit breaker
-Transformer (increase or decrease voltage)
-AC fuse
-rectifier bridge - diodes change AC to DC
-Voltmeter and Ammeter
-Surge Protection
-Filters
Esecondary = (Eprimary x Secondary turns) / primary turns
◉ Reference electrode location. Answer: the reference electrode should
be placed as close to the structure as practical. (underground piping or
tanks- over the center of the structure, multiple readings along the
structure as required)
internal surfaces of storage tanks, waterfront and offshore structures (as
close to the wall as possible)
◉ impressed current vs sacrificial. Answer: impressed current- higher
current, better control
COMPLETE QUESTIONS AND CORRECT
ANSWERS
◉ 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. Answer: - positive to anode
-negative to structure
- AC suppy
-AC circuit breaker
-Transformer (increase or decrease voltage)
-AC fuse
-rectifier bridge - diodes change AC to DC
-Voltmeter and Ammeter
-Surge Protection
-Filters
Esecondary = (Eprimary x Secondary turns) / primary turns
◉ Reference electrode location. Answer: the reference electrode should
be placed as close to the structure as practical. (underground piping or
tanks- over the center of the structure, multiple readings along the
structure as required)
internal surfaces of storage tanks, waterfront and offshore structures (as
close to the wall as possible)
◉ impressed current vs sacrificial. Answer: impressed current- higher
current, better control
