Actes du 3ème Colloque International sur la Corrosion et la Protection des Matériaux à Haute Température
J. Phys. IV France 03 (1993) C9-511-C9-519
Oxidation behaviour of simple and Pt-modified aluminide coatings on IN738 at 1100 °CY. Niu1, 2, W. T. Wu1, D. H. Boone3, J. S. Smith4, J.Q. Zhang1 and C. L. Zhen1
1 Corrosion Science Lab., Institute of Corrosion and Protection of Metals, Academia Sinica, Shenyang 110015, China
2 Instituto di Chimica, Facoltà di Ingegneria, Universita di Genova, Fiera del Mare, Pad. D, 16129 Genova, Italy
3 Boone and Associates, 2412 Cascade Drive, Walnut Creek, California 94598, U.S.A.
4 Howmet Corporation, Thermatech Coatings Division, 555 Benston Road, Whitehall, Michigan 49461, U.S.A.
The oxidation of both low and high-activity simple and Pt-modified aluminide coatings on nickel base superalloy IN738 has been studied in static air at 1100 °C up to 1000 h. For all coatings oxidation followed a parabolic law up to 400 h. The two Pt-modified coatings showed better protectiveness with lower mass gains and smaller rate constants, especially for long reaction times. The presence of Pt significantly improved the resistance to γ'-Ni3Al formation, promoted selective oxidation of aluminium by preventing the transport of other elements outwards to Al2O3 scale and resulted in the formation of purer, slower-growing and more adherent A12O3 scales, delaying the onset of scale spalling for two types of coatings and of oxide nodules growth for the high aluminium activity coating.
© EDP Sciences 1993