IFIS - LITORAL   24734
INSTITUTO DE FISICA DEL LITORAL
Unidad Ejecutora - UE
artículos
Título:
Surface chemical reactions induced on pyrite by ion bombardment
Autor/es:
FERRÓN, JULIO; RUANO, GUSTAVO; POMIRO, FERNANDO
Revista:
SURFACE SCIENCE
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2018 vol. 667 p. 138 - 147
ISSN:
0039-6028
Resumen:
Through X-ray photoemission spectroscopy (XPS), we studied the chemical changes induced in a natural crystal of pyrite (FeS 2 ) upon exposure to 4.5 keV He + beam. We found an important reducing effect induced by ion bombardment leading to the production of iron embedded in the pyrite matrix. Through a combination of the usual Doniach?Sunjic treatment and Factor Analysis of XPS yields, we were able of analyzing the full Fe 2p XPS signal. We could in this way distinguish Fe compounds with the same binding energy for the Fe 2p 3/2 yield. Our results show that He + bombardment disrupts the ionic environment producing S 2 − 2 and S 0 , Fe 2 + and Fe 3 + ions, and the reduction to metallic iron. The remaining pyrite matrix does not passivate the embedded iron structures, which are readily oxidized under air exposure. The oxide formed resembled that of magnetite from the XPS point of view. Further He + bombardment proved to be efficient to reduce the iron oxide back to iron again.