Iron passive films crystalline structure

Low-energy electron-diffraction (LEED) techniques are used to detect adsorbed films, including those responsible for passivity. Surface analytical techniques that can be used to study films on metals include Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), and others [18,19]. Using these advanced techniques, evidence has been developed to show that the passive film formed on iron in borate solution is an anhydrous, crystalline spinel with a Y-Fc203/Fe304-like structure [19]. 

---