Cathodic Protection Training Course

Module 2

Students are required to make two 'half-cells'.

This is necessary to make it clear that a copper/copper-sulphate electrode is a very simple article with no mystical powers or scientific properties that are difficult to understand.

It is simply a copper rod immersed in a saturated solution of copper sulphate. Copper sulphate is the result of disolving copper in sulphuric acid and therefore the scientific description 'in a saturated solution of it's own salts' is correct.

Copper sulphate crystals can be obtained from Ebay and Distilled water can be obtained from any garage.



Any clear plastic material can be used as the tube in which to place the copper sulphate crystals and the porous plug can be made from wood or gypson (plaster of Paris). Other domestic fillers can be used but they must be porous when they have set.



Scientists would have us believe that it is crucial to have pure copper and a pure saturated solution solution, but in fact you will be able to check this out when you have made the two electrodes.



You will be able to alter the purity of one cell and make a voltage measurement against the potential of the other.



Experimenting on a damp cloth or in a tray of wet sand will help you understand the function of the electrode.



The two Cu/CuSO4 electrodes will be used extensively during the remainder of this course.



The real purpose of the 'half-cell' is that of a convenient ground contact for buried pipelines and as a contact with the water in the case of submerged pipelines or structures.









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