NACE 2 CBT Study Guide with Complete Solutions

Corrosion is established as a what kind of current? - ANSWER-Direct Current All corrosion of iron at normal ambient conditions is ________________ ____________ - ANSWER-an electrochemical process Define, E=IR - ANSWER-E is driving voltage, I is current magnitude, R is circuit resistance. The less noble part of a corrosion cell - negatively charged - dissolves metallic iron then converts it to positively charged ions - generates electrons - where oxidation occurs. - ANSWER-Anode The more noble region on the electrode - where electrons are consumed - positively charged - where reduction occurs - ANSWER-Cathode The difference in potentials between the anode and the cathode create what? - ANSWER-Voltage difference, which is the driving force for corrosion. Allows for electrons generated at the anode to transport to the cathode. - ANSWER-Return path (metallic pathway) Conducts ionic current - water-based - contains ions - pathway to transport ions - carries corrosion current - ANSWER-Electrolyte Negatively charged ions - ANSWER-Anions Positively charged ions - ANSWER-Cations Four parts to a corrosion cell - ANSWER-Anode, Cathode, Return Path, Electrolyte Oxygen ____________ the rate of corrosion - ANSWER-Increases Corrosion proceeds ____________ in warmer environments than in cooler ones - ANSWER-Faster Chemical Salts like Sodium Chloride, act as a hygroscopic material (draws moisture from the air), which _____________ corrosivity in non immersed areas. - ANSWER-Increases The wetter the environment, the ____________ corrosion is likely to occur - ANSWER-more