The nature and relative amounts of the different species present in the surface region of RuO2 and RuO2‐TiO2 film electrodes, before and after an anodic polarization in 4Mnormalaq NaCl solution, have been determined by means of x‐ray photoelectron spectroscopy. The existence of a surface defect structure of RuO3 , analogous to that found on RuO2 powder, has been confirmed for both the RuO2 and RuO2‐TiO2 electrodes. Two different chlorine species, identified as chloride ions and adsorbed atomic chlorine, have been shown to be present on the surface of the electrodes used as anodes for the chlorine evolution.

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Three methods are proposed for the assay of traces of hafnium in aluminium metal by neutron activation analysis. In the first method, the isotope 179mHf (T = 19 s), produced is counted after anionic resin exchange‐separation in sulfuric acid medium. The two other methods, which are non‐destructive, are based on the formation of 180mHf (T = 5,5 h) and 179mHf (T = 19 s). The latter method comprises an instrumental separation.

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Die Natur und die relativen Anteile der im Oberflächenbereich von RuO2‐ und Ru02‐ TiOyFilmelektroden (durch thermische Zersetzung von RuCl3 und TiCl3 in Luft auf Ti‐Trägern) vorkommenden Spezies, vor und nach anodischer Polarisierung in 4 M wäßriger NaCl‐Lösung, werden mittels XPS bestimmt.