Non‐destructive characterization of chromium phosphate coated aluminium with SE and FTIRS correlated to surface analytical analyses by AES and TEM

Non‐destructive optical investigations (SE and FTIRS) of chromium phosphate conversion layers on aluminium are correlated to AES and TEM investigations. The AES results support the duplex model of the structure. FTIR‐spectra provide a non‐destructive characterization in agreement with the Auger data. Fitting the SE‐data with a proper model makes it possible to determine the thickness accurately. A correlation is made between the thickness obtained with SE, FTIRS and AES. It is shown that for thin layers a good agreement is obtained.