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NACE CP2 EXAM QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 BEST EXAM SOLUTION GRADED A+
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NACE CP2 EXAM QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 BEST EXAM SOLUTION GRADED A+
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NACE CP2 EXAM QUESTIONS AND ANSWERS LATESTUPDATE 2024/2025 BEST EXAM SOLUTION GRADED
A+
forms of corrosion - CORRECT ANSWERS 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 - CORRECT ANSWERS Low hydrogen, alkaline, easy polarization
Low PH - CORRECT ANSWERS high hydrogen, acidic, harder to polarize
High oxygen/High Hydrogen concentration - CORRECT ANSWERS harder to polarize,
work at the cathode only, called cathodic depolarizers.
factors affecting corrosion - CORRECT ANSWERS 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 - CORRECT ANSWERS a. corrosion current reduces with polarization
b. polarization increases with CP current applied
c. Occurs at surface of both anode and cathode.
shielding - CORRECT ANSWERS a. shorted casings
b. proximity of other structures
c. reinforced concrete
amphoteric materials - CORRECT ANSWERS corrode at low and high pH
,NACE CP2 EXAM QUESTIONS AND ANSWERS LATEST
UPDATE 2024/2025 BEST EXAM SOLUTION GRADED
A+
on potential - CORRECT ANSWERS native + polarization + IR drop
polarized potential (off) - CORRECT ANSWERS native + polarization
kirchoff's laws - CORRECT ANSWERS a. voltage (series circuits)
b. current (parallel circuits)
faraday's law - CORRECT ANSWERS W=KIT
relates weight loss of metal in a corrosion cell with time and current flow.
rate of corrosion - CORRECT ANSWERS directly proportional to current flow
cathodic protection limitations - CORRECT ANSWERS -shielding issues
-attenuation
-interference
-excessive current density
-contact with other metals (shorts)
measurement methods - CORRECT ANSWERS true voltage reading
voltmeter reading
% error calculations
effect of voltmeter resistance
IR oxidation - CORRECT ANSWERS loss of electrons, positive charge atoms (anode)
reduction - CORRECT ANSWERS gain of electrons, negative charged atoms (cathode)
correction methods
test stations - CORRECT ANSWERS allow electrical connection to structure for
potential measurements and bonds.
,NACE CP2 EXAM QUESTIONS AND ANSWERS LATEST
UPDATE 2024/2025 BEST EXAM SOLUTION GRADED
A+
Spans allow current and direction (IR drop).
inistall during construction
pH - CORRECT ANSWERS 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 - CORRECT ANSWERS - 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 - CORRECT ANSWERS 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 - CORRECT ANSWERS impressed current- higher
current, better control
, NACE CP2 EXAM QUESTIONS AND ANSWERS LATEST
UPDATE 2024/2025 BEST EXAM SOLUTION GRADED
A+
sacrificial- no power required, less maintenance, easy to install, less land
AC considerations - CORRECT ANSWERS capacitance, inductance, and resistance
hazardous AC potential - 15 Vac
Safe method of connecting ground0 cable to ground then to pipe
arcing hazards
corrosion rates from AC (current density)
switching or pulse rectifiers
Reference cells - CORRECT ANSWERS CuCuSO4- most common, (soil, fresh water)
AgAgCL - seawater
Calomel- lab
Hydrogen - standard (lab)
zinc- stationary
Cathodic Protection - CORRECT ANSWERS protect the cathode
attempts to bring the cathode potential as negative as the anode potential
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