The measurement on the surface condition of metals by means of ESCA

The electron spectroscopy for chemical analysis is introduced, with which information is obtained on the surface condition of solid specimens. The thickness of the surface examined by the ESCA is limited only within several tens of angstrom. An ESCA apparatus consists of a source of soft X-ray, an energy analyzer for the measurement of the kinetic energy of photoelectrons, a detector and measuring system, a sample treating room, and an evacuating system. The chemical shift of the Auger electrons emitted from the surface of a specimen is determined to give various informations. The soft X-ray usually adopted are Al(Kα)=1486.6 eV and Mg(Kα)=1253.6 eV. The narrower the line width of characteristic X-ray, the more accurate the determination. Typical electron energy analyzers are classified into static electric field type, magnetic field type, and the mixed type of both. The application of the ESCA to the surface of pure iron revealed that the surface became cleaner as the electrolytically polished surface was bombarded with argon ions, until the surface of matrix material, namely, pure iron surface was exposed. The application to the surfaces of nickel and copper also revealed various changes on the surface, which were reflected by the change of electron binding energy spectra. (Fukutomi, T.)