21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-4.2.2

THE EVOLUTION UNDER STRESS OF THE SUPERALLOY / PROTECTIVE COATING INTERFACE

Sanz A., Llanes L.*, Bernadou J. -P.**, Anglada M.*
CRD, Italy; *UPC/ETSII, Spain; **ENSAE, France

Keywords: stress, superalloy / protective coating interface

NiCoCrAlYTa coatings are frequently used to protect the components in the hot path of the gas turbines engines. A careful selection of the coating that offers sufficient chemical compatibility with the substrate and a low interdiffusivity is necessary for these high temperature systems. The diffusional phenomena of single -crystals, [001] oriented, of the AM-3 superalloy coated with a Low Pressure Plasma Spray (LPPS) NiCoCrAlYTa coating is described at two fixed times (8 hours and 89 hours) at 1323 K (l050°C) under different types of loading. The experimental conditions comprise oxidation treatments, creep and four point bending stress controlled tests with two different cycles 10-300-10 seconds and 10-10-10 seconds. Using the information obtained from Energy Dispersive microprobe Spectroscopy (EDS) the diffusional phenomena between the coating and the substrate is characterised and correlated with the chemical nature of the substrate and with the different types of loading.

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