Figure 12 shows the XRD spectra of a 560 AS
coating. No signi#cant increase in the oxide phase
formation is noted with increasing temperatures.
However, the chromium phases, an essential
element of this coating, are only observed in
the coating without heat treatment [20]. For
temperatures above 800ºC the presence of Fe2O3
oxide is well observed, and for treatments below
this temperature Fe3O4 and Fe2O3 oxides were
present [21].