INVESTIGATION ON STRUCTURE AND MORPHOLOGY OF THE THERMALLY TREATED GLASSY ALLOY (FE,CR)(80)(P,C,SI)(20) BY MEANS OF ESCA AND SEM EDXA/

Metallic glass ribbons of the chemical composition (Fe,Cr)(80)(P,C,Si) (20) have been thermally treated in the region between 530 and 980 deg rees C for 72 h. The SEM/EDXA investigations indicate that a phase tra nsformation takes place between 575 and 980 degrees C in a surface lay er of 5 mu m thickness. Thus, a Cr-rich phase occurs between 760 and 8 00 degrees C which is converted into an open-pore system between 850 a nd 900 degrees C, The oxidation process reaches its maximum at 760 deg rees C. The ESCA spectra of the material in the ''as received'' state and of the thermally treated samples indicate that different oxygen sp ecies are formed within the analysed surface layer of 10 nm. The oxyge n of the original material is incorporated as hydroxyl groups in speci es such as FeO(OH) and CrO(OH). After thermal treating the hydroxyl co ntent decreases and the oxide content increases. Species of Si exist i n the surface layer as SiO2-like compounds (peak at BE = 102.0 eV). A majority phase of transition metal phosphide species is coexisting wit h oxidised phosphate species.