Study of the Structure of Oxide Interface in the Pt-Rh Alloy by AP-FIM

This paper reports the study of structure of oxide interface in Pt-Rh alloy by atom probe field ion micro-scope (AP-FIM) which is well suited for the study of atom distribution with atomic scale at the surface and in-terface of alloy. AP depth profiles show that oxide interface exist in the Pt-Rh alloy which consists of PtO,RhO, PrOand RhO. The mechanism of oxidation of the alloy is considered as that first oxygen moleculesadsorbed on-to the surface of alloy then dissociate into oxygen atoms (0→2O). Consequently oxygen atomsdiffuse into interior through grain boundary forming oxide (M+O→MO). When the concentration of oxygencontinuously increases the dioxide (MO+O→-MO) forms.