Thermodynamic and Kinetics Aspects of High Temperature Oxidation on a 304L Stainless Steel

An AISI 304L stainless steel was oxidised in a TGA instrument at temperatures ranging from 800 to 1,200 A degrees C and for up to 3 h. The measured weight gains were fitted starting from the Wagner model, taking into account both a linear and a parabolic behaviour. Rate constants and activation energies were calculated. The fraction of oxides as a function of annealing time at 1,050 A degrees C were estimated by Rietveld refinement of XRD patterns of oxidised samples. These data were compared with the theoretical equilibrium conditions calculated with the Calphad approach. A simplified model able to describe the main kinetic features of the oxidation of an AISI 304L steel in industrial conditions (1,050 A degrees C and 0.087 atm of oxygen partial pressure) was developed.