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Pitting – Corrosion – Application Note 25

Latest updated: May 6, 2020

Abstract

Pitting is one of the most insidious forms of localized corrosion. This kind of corrosion occurs on passivable materials in media containing halide species. The resistance to pitting corrosion is evaluated using pitting potential determinations. A statistical variation of this parameter is usually observed which is this why a multichannel potentiostat is recommended for testing numerous sample at the same time and in same experimental conditions.

In this note, the pitting corrosion of four steel samples was studied using Linear Polarization (LP) and Multi-Electrode Potentiodynamic (MPP) techniques. A VMP3 with CE to the Ground mode and N’Stat box cable were used for simultaneous measurement on the four samples. The statistical evaluation of the pitting potential was determined using the Multi Pitting Statistics tool.

 

Introduction

The effect of the corrosion in our daily life can be underlined by its cost for society. For an industrial country, the cost is estimated at
3-4% of gross domestic product. Most metals are sensitive to corrosion in the presence of oxygen and humidity. The general equation of this oxidative process is described as follows…

 

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