Pstat

Select the potentiostat/galvanostat to perform the experiment. Each radio button corresponds to an installed potentiostat. You can select only one potentiostat at a time. Potentiostats that are already in use are marked with an asterisk. They can be selected but cannot be used.

Channel

There is one Channel Setup switch for each of the 8 channels. Click the checkbox to select a specific channel. As the script loops through the channels, it only runs tests on channels that are selected. The selected channel numbers do not have to be continuous.

Identifier

A string that is used as a name. It is written to the data file, so it can be used to identify the data in database or data manipulation programs.

The Channel Identifier string is virtually identical to the Test Identifier string. The only difference is that in multiplexed tests, the Identifier refers to an experiment run on a single cell and not to the entire experimental run.

System

Select a set of electrochemical parameters relevant to your particular test system. The parameters are recovered from the system parameter database file. The recovered parameters are all used for the calculation of the corrosion rate. They are the sample's equivalent weight, density, anodic β and cathodic β. When you attempt to run an experiment, the system searches the SYSTEM.SET file for a parameter set stored under the name in the System parameter. If the software finds no parameter set, an error message appears and you are returned to the Setup dialog box.

Area

The electrode area that is used in calculations. It can be set individually for each channel.

cm2

Notes

Enter several lines of text that describe the experiment. There is a separate entry for each channel in a multiplexed test. A typical use of Channel Notes is to record the experimental conditions for a data set.

The Channel Notes controls are similar to the Notes control described for non-multiplexed experiments.

Repeat Time

The time (specified as hours:minutes) between each test on the cell. For example, if the first test begins at 2:08 and the Repeat Time is 30 minutes, additional tests occur at 2:38, 3:08, 3:38, etc.

minutes (min)

Total Time

The duration of the experimental run. The script keeps track of the elapsed time from the start of the experiment. At the start of each test, the elapsed time is compared to the Total Time. If the elapsed time is greater than or equal to the Total Time, the experiment is halted and the Runner window is closed.

The Total Time is always entered in hours. Fractional hours can be entered as decimal numbers. To run a single test, enter a Total Time equal to the Repeat Time or simply run the Polarization Resistance experiment. For N tests, enter a Total Time = N × Repeat Time.

hours (hr)

Base Filename

Each channel has its own data file. The Base Filename is used to derive the filenames for these files. The filename for Channel N (1–8) is created by appending the character N to the Base Filename, then adding a *.DTA filename extension.

Example:

Save Raw Data

If enabled, individual Polarization Resistance data files are recorded and saved in addition to the Rp/Ec Trend data file.

The file names of the raw data files consist of the main file's name, followed by an underscore and the repeat number in which the data was recorded.

Analysis Region

The region over which the linear fit is performed on the data. It is bounded by x mV positive and negative from the open-circuit potential. For example, if the sample has an open-circuit potential of 0 V and the Analysis Region is 5 mV, the linear fit is performed on data from –5 mV to +5 mV.

mV

Initial E

The starting potential of the potential sweep during data acquisition. The allowed range is ±10 V with a resolution of 0.125 mV. Its accuracy is determined by the settings of Initial E and Final E.

volts (V)

Final E

The final potential of the potential sweep during data acquisition. The allowed range is ±10 V with a resolution of 0.125 mV. Its accuracy is determined by the settings for Initial E and Final E.

volts (V)

Sample Period

The spacing between data points. The minimum value that we recommend is 0.1 s. The longest Sample Period allowed is 600 s.

Extended description:

seconds (s)

IR Comp

Choose to turn iR-compensation either On or Off. Turning on IR Comp causes the applied potential to be adjusted for the estimated iR-drop.

Gamry potentiostats are able to estimate uncompensated voltage-drop caused by cell resistance. They do so by performing a current-interrupt experiment after every data point.

Equil. Time

The duration during which the cell remains at the initial potential, with the cell turned on before data acquisition begins. It allows the system to equilibrate before the actual experiment starts. No data are recorded during this step.

seconds (s)

Conditioning

You may condition the electrode as the first step of the experiment, for example to remove an oxide film from the electrode or to grow one. Conditioning ensures that the metal sample has a known surface state at the start of the experiment. This step is done potentiostatically for a set amount of time.

Extended description:

seconds (s), volts (V)

Initial Delay

Use the Initial Delay parameter to tell the system your definition of a stable potential and when to begin the actual measurement. If the absolute value of the Eoc drift-rate falls below the Stability parameter, the Initial Delay phase ends immediately and the experiment begins, disregarding the Time parameter. The drift rate can never fall below zero, so entering a Stability value of zero ensures that the Initial Delay will not end prematurely. A typical value is 0.05 mV/s. The lower limit of the Stability parameter is set by your patience. For example, a stability of 0.01 mV/s indicates a drift of less than 1 mV within 100 seconds.

seconds (s), mV/s