ABSTRACT
The modification of the composition of a ferritic Fe-23Cr-5Al alloy by addition of reactive elements in different forms was used in order to study their effect on the commencement and extent of scale spalling. The reactive elements have been added as their natural mixture (‘mischmetal’), as elemental hafnium and yttrium and as implanted yttrium. In addition, zirconium was used as an alloying element.
Oxidation was carried out in air in the temperature range 1473 to 1623 K. Short and long term experiments were performed.
It was found that the reactive elements improve the resistance of the scale to spalling. Their efficiency depended on the form of their presence in the substrate and on the reaction conditions.
