Stability of Aluminide Diffusion Coatings Expodes to High Temperature

abstract

English

Two types of aluminide diffusion coatings were created on Inconel 713LC nickel base superalloy substrate using powder liquid aluminizing method followed by two-stage heat treatment process. First type of coatings, prepared from pure aluminium powder in suspension, consists of four separate layers containing various portion of Al3Ni2, AlNi and AlCr2 intermediate phases. Second type of coatings preapared from aluminium and silicon suspension, where the amount of Al and Si powders Al was equal, consists of three separate layers containing AlNi, AlNi3, CrSi and Cr6Ni16Si7 phases. Stability of these coatings during exposition at the temperatures 900 and 1000 oC with dwell time up to 1000 hrs was topic of detailed investigation. Interactions running at the interfaces between both atmosphere and substrate influences in result the diffusion coatings stability. Within first hours of annealing first (often porous) layer adjacent to the atmosphere transform into the form of Al2O3 and/or Cr2O3 oxides. After that countinuous layer below the porous one starts to interact with atmosphere immediately. In contrast to the interactions at outer interface, by diffusion of species between the coating and substrate an interdiffusion region starts to form. The microstructures of these coatings interfaces were obtained by scanning electron microscope. Layer thickness measurements were realized by means of image analyses and chemical compositions were estimated by energy dispersive microanalysis measurements.

Superalloy; Coating; High Temperature Treatment; Diffusion; Oxidation

ČELKO, L.; KLAKURKOVÁ, L.; ŠVEJCAR, J.

28. 6. 2010

VUTIUM Brno

Antonínská 1, 601 90 Brno, Czech Republic

978-80-214-4112-5

Materials structure - Micromechanics of fracture, Abstract booklet

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