Corrosion Prevention & Protection Flashcards
7 cards from real SPED practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Corrosion Prevention & Protection flashcards as text
Which type of corrosion occurs when two dissimilar metals are in electrical contact in the presence of an electrolyte?
Answer: Galvanic corrosion
Galvanic corrosion occurs when dissimilar metals form an electrochemical cell in the presence of an electrolyte, causing the anodic metal to corrode preferentially.
In cathodic protection, which component of the system is intentionally corroded to protect the structure?
Answer: Anode
In cathodic protection, the anode (sacrificial or impressed current) oxidizes and corrodes to supply protective current to the cathode (the structure being protected).
What is the primary mechanism by which fusion-bonded epoxy (FBE) coating protects buried pipelines?
Answer: Acting as a physical barrier to moisture and oxygen
FBE coatings protect pipelines primarily by acting as a physical barrier that prevents moisture, oxygen, and electrolytes from reaching the pipe surface.
Which parameter is used to verify adequate cathodic protection of a pipeline per NACE SP0169?
Answer: -0.850 V vs. CSE
NACE SP0169 specifies a minimum pipe-to-soil potential of -0.850 V (vs. copper-copper sulfate electrode) as the criterion for adequate cathodic protection.
Stress corrosion cracking (SCC) in pipelines requires which three conditions to occur simultaneously?
Answer: Susceptible material, tensile stress, and corrosive environment
SCC requires the simultaneous presence of a susceptible material, sufficient tensile stress, and a specific corrosive environment — remove any one and SCC cannot initiate.
What type of corrosion is characterized by localized attack that forms pits on the metal surface?
Answer: Pitting corrosion
Pitting corrosion is a localized form that creates small cavities or pits penetrating deep into the metal while the surrounding surface remains relatively unaffected.
Which coating system is typically selected for high-temperature buried pipelines operating above 65°C (150°F)?
Answer: Three-layer polyolefin with high-temperature primer
Three-layer polyolefin systems with high-temperature-rated primers are selected for buried pipelines above 65°C because standard FBE and tape coatings can disbond at elevated temperatures.