Glossary – Definitions
Aqueous Corrosion Resistance of Nickel-based Alloys

Corrosion généralisée; General Corrosion

The most classic form of corrosion due to uniform electrolytic phenomena on the surface, manifested by a reduction in thickness if the corrosion products are soluble.

Corrosion localisée ; Localized Corrosion

It manifests itself in the form of material degradation and can take many different forms: pitting, cracks, erosion or abrasion, attacks on grain boundaries...

PREN; PREN

This index, whose name is made up of the abbreviation for "pitting resistance equivalent" plus the letter N, indicating that the index takes account of the presence of nitrogen in the material, was originally developed for stainless steels, to compare their resistance to localized corrosion. However, it is now also used for nickel alloys. It is calculated by the formula :