Proceedings of the 3rd International Symposium on High Temperature Corrosion and Protection of Materials
Actes du 3ème Colloque International sur la Corrosion et la Protection des Matériaux à Haute Température

J. Phys. IV France 03 (1993) C9-569-C9-578
DOI: 10.1051/jp4:1993960

Protective effect of coatings on the corrosion behaviour of Ni based superalloys in gas turbines atmospheres

F. Coen-Porisini¹, R. Saiu¹, F. Dos Santos Marques¹ and F. Bregani<sup>2

1</sup>  Commission of the European Communities, Joint Research Centre, Ispra Establishment, Institute of Advanced Materials 21020 Ispra (Varese), Italy
²  ENEL-CRTN, Via Rubattino, 54, 20134 Milano, Italy

Abstract
The corrosion of Ni based superalloys IN 738, IN 792, UD 720 and MA 6000 in gaseous atmospheres were studied at three temperatures: 800 °C, 950 °C and 1100 °C. The corrosive atmospheres, simulating the composition of combustion gases of turbines, were highly oxidizing (Ar + 10% O₂) and contained low amounts of SO₂. The effect of an anticorrosive coating, of the type MCrAlY, was studied in corrosion tests of coated and uncoated specimens. Weight change measurements, together with SEM analysis were used to determine the extent and morphology of the corrosion. The effect of the MCrALY coating was to reduce the extent of the corrosion due to the formation of a protective Al₂O₃layer.

© EDP Sciences 1993