OXIDATION MECHANISMS OF LOW ENERGY-HIGH FLUX NITRIDED ODS FeAl INTERMETALLIC ALLOY

Fernando Pedraza (1) , Jean-Luc Grosseau-Poussard (1) , J.F Dinhut (1)

1 LEMMA - Laboratoire d'Etude des Matériaux en Milieux Agressifs

Microscopy studies of low energy-high flux nitrided ODS FeAl Grade 3 intermetallic alloy reveal a surface containing a random distribution of protrusions anchored by yttria particles. The cross section analyses show the formation of an outer compact layer containing hexagonal AlN followed by an inner diffusion layer containing AlN and a segregation of α-Fe. The high temperature isothermal oxidation behaviour is subsequently evaluated at 800° C for 24 h. The nitrided layer is observed to induce a change in the oxidation mechanisms compared to the untreated material. As a result of the outer diffusion of Fe a Fe2O3 scale is first established at the gas/metal interface, followed by an intermediate α-Al2O3 layer. The original substrate also seems to be oxidised to give rise to a spinel layer the oxide/alloy interface.

Mots clés: FeAl Grade 3; high temperature; oxide scales; yttria; TEM

Domaines: Matériaux

Fernando Pedraza, Jean-Luc Grosseau-Poussard, J.F Dinhut. OXIDATION MECHANISMS OF LOW ENERGY-HIGH FLUX NITRIDED ODS FeAl INTERMETALLIC ALLOY. Materials at High Temperatures, 2005, 22, pp.283-286. ⟨10.3184/096034005782744209⟩. ⟨hal-00512787⟩