Angular resolved XPS

The application of XPS to the investigation of passivity of Co shows a complicated sequence of anodic oxides, which are formed and may be reduced according to the electrode potential. Angular resolved XPS suggest an outer position of hydroxide and an inner position of oxide. 

Ni is a frequent component for alloys as e.g. for stainless steels. Polarization curves of Fe53Ni and FelONi still show features known for pure Ni (Fig. 5). The current increase and the peaks in the transpassive range are suppressed to a large extent in acidic and alkaline solutions due to the influence of Fe [15, 48], Angular resolved XPS measurements indicate a bilayer structure of the passive film with an outer hydroxide and an inner oxide part. Circa 1 nm hydroxide is found with no change with the electrode potential. The oxide part increases linearly with the potential up to 5 nm and levels off to a constant value for the transpassive potential range at 0.70 V in 1 M NaOH and at 1.40 V for pH 2.9 [15, 48], At 0.70 V in 1 M NaOH one observes... 

Photoelectron spectroscopy has also been applied to the study of thin SiO- layers on Si (32,33). Angular resolved XPS (3 —36) can be used to produce non-destructive depth profiles and thereby avoid the ion-induced damage described by Thomas (5). Moulder and Hammond (37)... 

Presence of Titanium Oxidation-State Species in a PtlTiO (lOO) System as Determined by Angular-Resolved XPS... 

The surface sensitivity of the technique can therefore be enhanced by lowering the angle S by positioning the sample so that the photoelectronic emission is grazing to the surface. These analyses are known as AR-XPS (Angular Resolved XPS). 

Figure 1-24. Angular resolved XPS analysis of a bilayer structure. Fe(II)/Fe(III) passive layer on iron developing at =-0.16 V in 1 M NaOH with passivation time tp (Haupt and Strehblow, 1987a).

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