Experimental Sequence for Critical Pitting Temperature

Run the Critical Pitting Temperature standard technique by selecting Experiment>Critical Pitting-Temperature>Critical Pitting Temperature from the Framework™ menu bar. This initiates the following sequence of events:

  1. The Framework creates a Runner window, and the Critical Pitting Temperature.exp script is run in this window.
  2. In the runner window, the script displays a Setup Dialog Box which becomes the active window. This dialog box allows you to view and edit the experiment parameters. Clicking the OK button accepts the parameters and starts the experimental run.
  3. The script now obtains the use of the potentiostat and temperature controller specified during setup, and opens the data file specified in the Output File field of the Setup Dialog Box. If the potentiostat or temperature controller is in use, or the data file cannot be opened, the script returns you to the Setup dialog box.
  4. Header information is written to the data file. Header information consists of the analysis tag, the time and date the experiment was started, and a list of the setup parameters.
  5. The optional electrode conditioning, specified during Setup, is performed. Conditioning is done by applying a fixed potential for a specified time duration to the specimen. This establishes a known surface state on the specimen. A plot of current versus time is displayed during Conditioning.
  6. The initial Open Circuit Delay is performed. This is done to establish Eoc at room temperature. The measurement lasts for 10 minutes. To modify the initial O.C. Delay you must edit the CPT script.
  7. The initial temperature is sent to the temperature controller. The script then enters a loop in which it continuously reads the current cell temperature until the cell reaches the set-point.
  8. Once the cell gets to the set temperature, the script runs an Open Circuit Delay for the duration specified during Setup.
  9. At this point the actual data are acquired. The potentiostat sets the applied potential specified during Setup, and begins acquiring current-versus-time data. Data are acquired for the time specified in the Run Duration field of the Setup dialog box, or until the current reaches the current limit. In either case the scan terminates and the script writes the data to the data file.
  10. If the data-acquisition ended because the current exceeded the current limit, the script terminates. If the current did not exceed the limit, the script sets a new temperature and returns to Step 7. If the new temperature exceeds the Final T parameter, the script terminates.