Enhanced Cyclic Oxidation Resistance of a Single Crystal Superalloy with an Electrodeposited Reactive Element Oxide Coating

Abstract:

Cathodic electrodeposition was used to generate a rare earth (RE)-containing deposit on a single crystal Ni-based superalloy. The deposition parameters were optimised in order to get a RE oxy-hydroxide coating with a “well-fitted” dry-mud like morphology, i.e. presenting a multi-cracks network. A further thermal treatment was applied to dehydrate the deposit to obtain a well crystallised oxide coating (RE_xO_y). The uncoated and RE_xO_y-coated substrates were then submitted to cyclic oxidation tests at 1100°C in laboratory air. They demonstrated the efficiency of the coating as uncoated samples severely spalled after a few cycles whereas the coated ones did not lose their protective oxide layer even after 2000 cycles. This result was attributed to the formation of a duplex oxide scale very similar to that obtained on g/g’ coatings, to the presence of nanograins at the RE_xO_y/scale interface and to the Hf-rich oxide pegs at the scale/substrate interface.

• Periodical: Materials Science Forum (Volume 696)
• Pages: 278-283
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.696.278
• Online since: September 2011
• Authors: Fernando Pedraza-Diaz, Baptiste Bouchaud, J. Balmain, G. Bonnet, Justine Menuey
• Keywords: Alumina, Cathodic Electrodeposition, Cyclic Oxidation, Reactive Element (RE)

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