Galvanostaircase Polarization (GSCP)

Last updated: August 15, 2017

What Does Galvanostaircase Polarization (GSCP) Mean?

Galvanostaircase polarization (GSCP) is a galvanostep technique for polarizing an electrode in a series of constant current steps wherein the time duration and current increments or decrements are equal for each step.

The galvanostaircase polarization method has been used to study the localized corrosion of aluminum alloys. It may serve as a guide for examination of other alloys. This method of polarization has overcome the shortcomings of the potentiodynamic method.


Corrosionpedia Explains Galvanostaircase Polarization (GSCP)

Galvanostaircase polarization is a polarization technique which was developed to determine the relative susceptibility of aluminum alloys to localized corrosion (pitting and crevice corrosion). This technique allows the measurement of the breakdown and the protection potentials in controlled current mode. This test method also describes a procedure that can be used as a check for one’s experimental technique and instrumentation. In this technique, the current is step increased and potential measurement is made until the time rate of change in potential approaches zero.

Galvanostaircase polarization (GSCP) prevents an induction effect and current hysteresis; however, it is subject to voltage hysteresis, which can make the determination of protection potential difficult, if not impossible. Fortunately, voltage hysteresis can be avoided easily by staying at low current levels and charge densities. Therefore, the potentiostaircase polarization method was used to eliminate hysteresis.

In the galvanostaircase technique, changes in potential are monitored for a sample that is polarized in a series of current increments or decrements. Potential is measured versus time at various constant applied currents that are incrementally increased in steps, then reversed and decreased. In the case of passive materials, a potential rise indicates passive film growth, while a decline indicates breakdown and growth of local corrosion sites.


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