What does a Tafel plot tell you?

A Tafel plot is a graphical plot (usually logarithmic) showing the relationship between the current generated in an electrochemical cell and the electrode potential of a specific metal. These plots are usually generated based on electrochemical experiments performed under controlled conditions.

How do you plot Tafel?

The Tafel plot can be determined by plotting the log of the electrochemical current as a function of the overpotential. The overpotential is the difference between the applied potential and the equilibrium potential (i.e every Faradaic reactions have an equilibrium potential based upon reaction free energy.

How do you plot Tafel plot in origins?

Once you obtain the tangent line equation in the output sheet, you can go to menu File->New->Function Plot->New 2D Function Plot…, In the dialog, type in the line function and add the line to the graph.

How does Tafel plot calculate corrosion rate?

The anodic or cathodic Tafel plots are described by the Tafel equation: η = overvoltage, the difference between the potential of the specimen and the corrosion potential. This equation has the form y = mx + b, so a plot of η vs. log i is a straight line with slope β.

How do you make a Tafel slope?

plot the log value as x axis and potential as y axis. Zoom the graph in the kinetically controlled region. You will get the tafel plot. then you can straight fit the top portion of the tafel plot to get the tafel slope.

What is Tafel fit?

The Tafel Fit command is used to calculate a corrosion rate from Tafel or potentiodynamic data. Tafel analysis assumes that the corrosion reactions are under kinetic control.

What Is decade in Tafel plot?

Decade means for example 1 mA to 10 mA, or 10 mA to 100 mA, in log scale -3 (0.001 A) to -2 (0.01 A), or -2 (0.01 A) to -1 (0.1 A). So the Tafel slope of +/-120 mV/dec means that between 1 and 10 mA potential increase (+) or decrease (-) for 120 mV.

What is beta in Tafel equation?

β is the reaction’s Beta coefficient (constant for a given reaction); β has units of volts/decade. The Tafel equation describes the behavior of one isolated reaction.

How do you calculate exchange density from Tafel plot?

The exchange current density can be obtained from Tafel plot (log I vs. V, then extrapolate current to V = 0). In that case you will have to do LSV rather than CV. The magnitude of exchange current density is measure of rate of reaction.