Thermodynamics & Kinetics of Corrosion Flashcards
Determines whether the reaction is spontaneous, non-spontaneous or at equilibrium.
gibbs free energy
Is a quantitative measure of a chemical reaction’s tendency to start, which includes the reaction of a metallic material with its environment.
Gibbs free energy change (ΔG)
Used to describe the reduction of G along with the reaction time.
reaction affinity
If ΔG is positive, reaction is
non-spontaneous
An electrochemical reaction where metal atoms lose electrons and form metal ions.
oxidation
An electrochemical reaction where non-metallic substances such as oxygen gain electrons
reduction
Allows for the flow of ions and electrons between the metal surface and the surrounding environment.
electrolyte
The overall corrosion reaction can be described in terms of _____ involving oxidation and reduction.
half-reactions
The corrosion of metals occurs within a localized electrochemical cell known as a _____.
corrosion cell
In a corrosion cell, it is where oxidation occurs, leading to the release of metal ions.
anode
In a corrosion cell, reduction reactions take place at the ____, where electrons are consumed.
cathode
Is the potential difference measured under standard conditions (1 M concentration, 1 atm pressure, and a temperature of 25°C) for a half-cell reaction relative to the SHE.
standard electrode potential (E°)
It is the half cell in which hydrogen gas is bubbled over a platinum electrode immersed in a solution having a known concentration of hydrogen ions.
standard hydrogen electrode
Relations between the energy and the potential of a cell to the concentrations of participating ions and other chemical species
Nernst equation
Outline regions of active corrosion, oxides/hydroxides formation, and thermodynamic immunity for a metal.
potential-pH diagram / Pourbaix diagram
