Oxidation of Ni-Cr alloy at intermediate oxygen pressures. II. Towards the lifetime prediction of alloys

International audienceThe formation of protective Cr 2 O 3 layer on Ni-Cr alloys depends on (i) the chromium concentration at the alloy/oxide interface and (ii) the chromium diffusion in the alloy from the core towards the surface. A sufficient interfacial chromium content and chromium gradient are necessary to sustain the selective external oxidation of chromium. Ni-30Cr samples have been oxidised at 1150 • C in 10 −13 up to 10 −3 atm O 2. Analytical methods are used to model the diffusion in steady-state conditions and to predict the lifetime of the alloy. The interdiffusion coefficient is found equal to 1.2 × 10 −10 cm 2 s −1