Study of selective oxidation by means of glow discharge optical emission spectroscopy
Résumé
In the continuous annealing process, steel sheets are annealed at 800 °C in an atmosphere of nitrogen and hydrogen (5 vol.%) containing low water partial pressure (20–50 Pa). Under these conditions, the most oxidizable alloying elements in the steel segregate towards the surface where they form oxide particles. The Mn, Al, Si and B concentration gradients resulting from this selective oxidation were measured as a function of annealing time by the glow discharge optical emission spectroscopy method. The manganese and silicon diffusion coefficients in steel were then estimated using Wagner's diffusion model.