The XPS spectra of gamma-alumina were collected with a VSW HA150 using monochromatic Al Kα x-radiation. Monochromatic radiation provides a distinct clarity to the peak structure in the valence band of gamma-alumina due to the absence of interfering x-ray satellites from the intense O 2s region. Variations in the intensities and peak separation of the two-peak structure in the valence bands of the oxides, hydroxides, and oxyhydroxides of aluminum allow one to distinguish between these compounds. The valence band, survey, and the Al 2s, Al 2p, O 1s, and C 1s core levels are reported.

Phosphate films with thicknesses on the order of the original native metal oxide have been formed on oxide-free aluminum and iron surfaces by electrochemical treatment in 5M phosphoric acid. Electrochemistry was performed under inert atmosphere in a previously described anaerobic cell. The metal phosphate films formed under these conditions were studied by core level and valence band X-ray photoelectron spectroscopy (XPS) with the valence band spectra interpreted by spectra generated from band structure calculations. Valence band studies showed that the metal surfaces consisted of a metal phosphate film bonded directly to the metal substrate in the absence of any form of metal oxide. An analysis of the inner valence band region around 25 eV indicates considerable difference between oxidized aluminum and iron compounds and the metal phosphates. The phosphate film initially formed on aluminum is compatible with metaphosphate. This unusual surface is stable in atmosphere and may have significant potential based upon known advantages provided by phosphated surfaces. This study provides a detailed analysis of a recent patent report of oxide free phosphate surface films formed on metal surfaces that are stable under ambient atmosphere.

The XPS spectra of aluminum phosphate were collected with a VSW HA150 using monochromatic Al K ␣ x-radiation. Monochromatic radiation provides a distinct clarity to the rich peak structure in the valence band of aluminum phosphate due to the absence of interfering x-ray satellites from the intense O 2s region. The valence band region shows the characteristic phosphate peaks at 13.79 eV and 10.69 eV. The valence band, survey, and the Al 2s, Al 2p, O 1s, and C 1s core levels are reported.

The determination of the detailed chemical nature of oxidized aluminum species is an essential requirement for the study of many important practical aspects associated with aluminum metal and its compounds. While thick oxidized films of aluminum metal can be easily characterized by x-ray powder diffraction when the films are crystalline, thin amorphous films are very difficult to characterize. In this article, a study of the valence band x-ray photoelectron spectrum of aluminum oxides, hydroxides, and oxyhydroxides is reported using monochromatic aluminum Kα X radiation. The valence band spectra obtained are shown to have significant differences for different oxidized aluminum species, and can be well understood by comparison with spectra generated from cluster and band structure calculations. This study compliments earlier published studies from this research group using achromatic radiation, and demonstrates how the use of monochromatic X radiation allows a more conclusive distinction to be made among oxidized aluminum species.

The XPS spectra of corrundum were collected with a VSW HA150 using monochromatic Al Kα x-radiation. Monochromatic radiation provides a distinct clarity to the peak structure in the valence band of corrundrum due to the absence of interfering x-ray satellites from the intense O 2s region. Variations in the intensities and peak separation of the two-peak structure in the valence bands of the oxides, hydroxides, and oxyhydroxides of aluminum allow one to distinguish between these compounds. The valence band, survey, and the Al 2s, Al 2p, O 1s, and C 1s core levels are reported.