XPS for Environmental Studies

Chromating of electrogalvanized items is widely used to provide corrosion resistant surfaces for steel and automotive materials. As part of the regulations for hazardous material disposal, WEEE/RoHS directives require all chromated materials be tested for hexavalent chromium and trivalent chromium. Since there is no equipment capable of analyzing hexavalent chromium, testing is usually done by removing the chromated layer to be analyzed in emission spectrography such as ICP. XPS is attracting attention as a tool effective in identifying the valence number of chromium, because it acquires information from areas a few nm deep from the surface, and is capable of high sensitivity analysis of the oxidation state (valence number) of thin materials.