Surface Reaction and Transport in Oxides Formed on FeCrAl Alloys in High Temperature Nitridation Environments

• An extended experimental study on corrosion of commercial FeCrAl alloys in predominantly N-2 atmosphere at high temperatures raises fundamental questions concerning nitrogen permeation through oxide scale components, each commonly perceived to constitute a robust barrier. State-of-the-art microscopy combined with DFT calculations is employed to unravel the underlying mechanisms for how chromia nodules support nitrogen dissociation and subsequently act windows for internal nitridation. A similar analysis addressed the role of yttria nodules shown to exhibit apparent expulsion of nitrogen, while favoring rapid alumina growth underneath the nodules. In this case, as for the slowly growing bare alpha alumina scale, the origin for the protection towards nitrogen permeation was identified as the inability to satisfy the necessary conditions for N-2 dissociation.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Annan materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Other Materials Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik -- Korrosionsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering -- Corrosion Engineering (hsv//eng)

Nyckelord

Oxide transport properties

Surface reaction

DFT

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