Oxidation behaviour of a next generation polycrystalline Mn containing Ni-based superalloy

A prototype next-generation superalloy containing 1 at.% Mn was oxidised in air at 800 degrees C for 100 h, and compared with a commercial Ni-based superalloy. The oxide scale consisted of a multi-phase layered structure measured by Atom Probe Tomography as uppermost NiCr2Mn2O4, followed by an inhomogeneous mix of Cr2O3, spinel MnCr2O4 and rutile (Ti,Cr)O-2. The Mn did not form a homogeneous, surface passivating oxide layer. Despite this, the alloy showed a 3 x reduction of oxide thickness compared to a commercial polycrystalline Ni-based superalloy. (C) 2015 Elsevier Ltd. All rights reserved.