Stability of External alpha-Al2O3 Scales on Alloy 602 CA at 1100-1200 A degrees C
Journal article, 2018

An external ultrathin alpha-Al2O3 scale grown on the Ni-base alloy 602 CA during air oxidation at 800 A degrees C was characterized by means of high-resolution TEM/EDX and electron diffraction. Alloy samples pre-oxidized at 800 A degrees C were subsequently exposed at 1100, 1150 and 1200 A degrees C for up to 100 h. Whereas the external alumina remained stable at 1100 A degrees C, with the increasing exposure temperature, the pre-grown alumina scale tended to break down resulting in an external chromia scale accompanied by internal alumina precipitation. The transition from external to internal Al oxidation was investigated using SEM/EDX/EBSD. The critical Al depletion at the scale-alloy interface during the post-exposure at 1100-1200 A degrees C was modeled using the CALPHAD-based thermodynamic-kinetic approach.

Alumina scales

Alloy 602 CA

Pre-oxidation

Breakaway

Depletion

Internal oxidation

Author

Anton Chyrkin

Chalmers, Physics, Materials Microstructure

R. Swadzba

Bardin Institute for Ferrous Metallurgy

R. Pillai

Forschungszentrum Jülich

T. Galiullin

Forschungszentrum Jülich

E. Wessel

Forschungszentrum Jülich

D. Gruener

Forschungszentrum Jülich

W. J. Quadakkers

Forschungszentrum Jülich

Oxidation of Metals

0030-770X (ISSN) 1573-4889 (eISSN)

Vol. 90 1-2 119-133

Subject Categories

Ceramics

Metallurgy and Metallic Materials

Corrosion Engineering

DOI

10.1007/s11085-017-9827-0

More information

Latest update

9/12/2018