Résistance à la corrosion des alliages de titane, de zirconium ou de tantale dans les milieux chlorés ou chrorurants^*

Caractères principaux

Corrosion resistance of titanium, zirconium or tantalum alloys in chlorinated or chloridizing environments - key features

Ingénieur ECP, Directeur Recherches et Développement de la Compagnie Européenne du Zirconium Cezus

Abstract

In their general corrosion resistance, the three materials titanium, zirconium and tantalum can be classed upwards in that order. However, titanium (for oxidizing environments) and zirconium (for reducing environments are complementary, where as zirconium alone out of the three metals is able to resist alkaline solutions. These different behaviours are illustrated schematically in figure 22, where the range of applications of each material is outlined by a rectangle having as its top side each of the lines plotted on the diagram. The respective areas for titanium, zirconium and tantalum are clearly differentiated and the beneficial effects of alloying additions in the case of titanium are evident.

Economically, the use of these materials in the higher price bracket is justified in aggressive environments whenever a reduction in maintenance overheads, continuous production, productivity gains through higher operating temperature or pressure, and high purity products obtained under top safety conditions, are management priorities.