Predicting the depletion of chromium in two high temperature Ni alloys

The oxidation resistance of the high temperature Ni-Cr alloys alloy 601 and alloy 602 CA was studied. Based on microanalysis data from cyclic oxidation experiments performed in a burner test rig, the total loss of chromium in the alloy was determined. A numerical analysis using the general diffusion equation was performed to model the mass transport for the observed chromium loss. Chromium depletion profiles were calculated with an effective diffusion coefficient derived from the data of the shortest exposure time. Good agreement was found between the measured and the computed chromium concentration at the alloy-oxide interface for longer exposure.

► Oxidation resistance of two chromia-forming high temperature Ni alloys is studied.
► Total chromium loss was experimentally determined from cyclic oxidation tests.
► Diffusional transport of chromium modelled with an effective diffusion coefficient.
► Computed chromium concentration profiles agree well with experimental data.
► Chromium depletion was computed for times exceeding the experimental duration.