Corrosion Questions Flashcards
In its simplest form an atom is a positive nucleus surrounded by electrons. What charge are these electrons?
Negative
When an electron is either added or taken from the group surrounding an atom, the overall charge is no longer zero. The condition of the atom at this stage is called:
Ionic
If the atom loses an electron it becomes a positive ion and has a positive charge. This may be referred to as a:
Cation
Which of the following reactions occurs at the cathodic site?
Reduction
The anode usually corrodes because of a:
Loss of electrons
‘Pitting’ is which of the following types of corrosion?
Localised
Corrosion with the presence of oxygen is known as:
Aerobic corrosion
A form of corrosion that forms along the toe of a weld due to higher energy regions is often called?
Weld decay
Fretting corrosion occurs at areas:
That are subjected to vibration and slip
Which of the following environmental factors affect the rate of corrosion?
Answer:d All of the above
a. Temperature
b. Water flow rate
c. The pH of the electrolyte
d. All of the above
A working riser which becomes hot during service:
Is particularly susceptible to corrosion and must be inspected more frequently
Steel corrodes least when it is submersed in an electrolyte that has a pH value between:
11-12
Which of the following CP readings taken with a bathycorrometer indicate that the structure is adequately protected?
-875 mV
Which of the following CP readings indicates overprotection of the structure, increasing the risk of hydrogen embrittlement?
More negative than -1000mV
For an ICCP system to function correctly, which terminal should be connected to the structure?
Negative
