Potentiostatic Experimental Sequence
Run the Potentiostatic standard technique by selecting Experiment>DC Corrosion>Potentiostatic from the Framework™ menu bar. This initiates the following sequence of events:
- The Framework creates a Runner window, and the Potentiostatic.exp script is run in this window.
- The script creates the Setup dialog box and accepts changes in the experimental parameters.
- The script now obtains the use of the potentiostat specified during Setup, and opens the data file using the Output name. If the potentiostat is in use or the file cannot be opened, the script returns you to the Setup dialog box.
- The file header information is written to the data file. This header information includes
This information is written to the file prior to data-acquisition. If the experiment is aborted, the output file contains only this information.
- Tags identifying possible analyses
- The current time and date
- A list of the Setup parameters
- The script conditions the electrode if Conditioning was specified in the Setup. Conditioning is done by applying a fixed potential for a defined time. It establishes a known surface state on the corrosion specimen. A plot of current versus time is displayed during the Conditioning.
- The cell is turned off and the specimen's Eoc is measured.
- If an Init. Delay is turned on in the Setup, this step lasts for the time specified as the Init. Delay time, or until the potential stabilizes. If no Init. Delay is specified, this step only lasts long enough for Eoc to be measured. A plot of potential versus time is always displayed. The last measured potential is recorded as Eoc.
- Data-acquisition occurs. The sample is potentiostated at the Initial E, a delay of one sample period occurs, and a reading of the current is taken. A delay of one Sample Period occurs, and the next current reading is taken. This process of delaying and acquiring data points continues for a time set by Initial Time Setup parameter. The potential is then stepped to the Final E. The process of taking current readings is continued at this new potential for a time set by the Final Time parameter. At each point the current range is automatically switched to the optimal range for the measured cell current. If IR Compensation has been selected, the applied potential is corrected for the measured IR-drop of the preceding point. A plot of current vs. time is displayed during the scan.
- The data are written to the output file and the script cleans up and halts.
- Once the scan is over, the cell is turned off. The acquired data are written to the output file.
- The script then waits for you to click the Skip button. When you do, the script closes everything that is open, including the Runner window.