Corrosion Flashcards
What is oxidation?
Oxidation is the loss of the metal atoms valence electrons and occurs at the anode.
What is Reduction?
Reduction is the absorption of electrons which takes place at the cathode
for corrosion to proceed what condition must be true?
there must be at least one reduction and one oxidation rxn occurring.
how is the driving potential for oxidation to proceed measured?
it is measured as voltage.
what must be present when two metals are connected for oxidation to proceed?
an electrolyte must be present for oxidation reactions to proceed.
what are the two categories of metals?
1 - Noble (nonreactive and inert). 2- Active Elements (highly Anodic or reactive)
what can we use to compare the oxidation and reduction potentials of different metals?
The standard electrode half cell.
How do you measure the corrosion rate?
Use the Corrosion penetration rate formula.
What is the value of K in the CPR formula?
87.6
What is kinetics ?
How quick a material is degrading.
how can the corrosion rate be indicated?
by the rate of current measured in a cell.
what is the special condition called when the oxidation and reduction rates are balanced?
Exchange current density.
what is the slowest rxn or mechanism involved called?
the Rate Determining Step.
how do we protect materials from corrosion?
Sacrificial anodes, Passivity, Impressed current cathodic protection, Galvanizing,
what are the forms of corrosion?
Uniform surface, galvanic, crevice, inter granular, selective leaching, Erosion, Stress.
