Examination of Passive Films on Iron-Nickel Alloys by Auger Electron Spectroscopy

Detailed analysis of anodic films formed on amorphous iron-nickel alloys containing phosphorus, boron, and molybdenum has been performed by Auger electron spectroscopy. These films contain considerable quantities of P and B both of which are highest at the metal/film interface. Phosphorus accumulates on the metal side of the interface while boron accumulates on the film side, with continuous variation throughout the film thickness. In the film phase, phosphorus shows complex oxidation states. Molybdenum is also found in the films at low concentrations. Polarization curves show that these alloys exhibit greater passivity in 1M HCl than a comparable polycrystalline iron-nickel alloy.