Nace CP 1 - Demonstrate Change in Polarized Potential with Time; Experiment to Demonstrate Change in Polarized Potential with Time

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Underground Corrosion Control 3:38

CP 1 – Cathodic Protection Tester Course Manual

02/01/05

Experiment 3.2 Demonstrate Change in Polarized Potential

with Time

NOTE: Instructor will demonstrate this experiment.

PROCEDURE

Reference Electrode

Magnesium Anode

–

Copper Sheet

Tray with Tap Water

Experiment to Demonstrate Change in Polarized Potential with Time

Part A

1. Place copper sheet in one end of tray and magnesium anode in opposite end.

2. Add 1-1/2 inches of tap water to the tray.

3. Connect anode to copper sheet as shown and measure initial cathodic protection current

and polarized potential of the structure. (A second meter from another kit can be used to

obtain current flow (amperes) or a single meter can be relocated to obtain the

information.)

Part B

1. Re-measure the polarized potential of the structure at intervals until relatively stable.

Part C

1. Leave overnight.

2. Measure pH.

3. Disconnect anode and take depolarized readings.