Study of copper surface oxidation by grazing angle X-ray excitation

The results show small variations among the different spectra measured for each sample. The most significant variations are observed for the first measurement (after evaporation) and the last one (after the heating in oven). The mathematical model works correctly for a two-layer scheme but shows inconsistencies for more complex schemes. This indicates that the stratified model is not appropriate for continuous media due to the nature of the theoretical assumptions in which the stratified model is based. Our results show also that the surface oxidation process takes place in the first moments of exposition to air and does not progress afterwards except if the sample is heated.