Thickness determination of oxide layers on spherically‐shaped metal powders by ESCA

Abstract

Abstract The effect of the spherical shape of powder on the determination of oxide thickness in ESCA analysis in investigated. A theoretical model, which takes account of the angular dependence of the X‐ray flux, the photoelectron intensity and the etch rate, is outlined. The model agrees well with experimental depth profiles obtained for Al and Fe powders covered with thin oxide layers (14–20 Å). By using an effective escape depth factor, the thickness of thin oxide layers can be estimated from the oxide and metal intensities. The thickness of oxide layers greater than three times the electron mean free path can be estimated from the etch depth where the metal itensity is 65% of its maximum.