| XPS provides information on the thickness and chemical composition of oxides formed the surfaces of Aluminum alloys under different process operations, such as cutting, extrusion, rolling, forging and heating. This knowledge of the dependence of surface characteristics on process conditions and alloy composition is of special interest since it can be used to assist construction of emissivity compensation algorithms, which provide accurate and reliable non-contact (radiometric) temperature measurements during manufacturing.;Angle Resolved XPS (ARXPS) was used for surface analysis of freshly-processed Al-alloys. For full quantitative ARXPS data analysis we have improved an existing model in the literature to account for the changes of the emission angle of photoelectrons (take-off angle) across the surface associated with roughness geometry. This model, based on an assumption of a sinusoidal surface roughness predicts with accuracy the oxide layer thickness and gives a very good fit to the angular dependent XPS intensity ratios. Oxide layer thicknesses of 40-70 A are typical of freshly processed surfaces of a variety of alloys.;A combination of Ar;Emissivity measurements of the heated alloys showed that the oxide layer thickness and the carbon and graphite surface residue for the 6061 alloy, may control the emissivity behavior. |
