Metal, Chemical Reactions with Metals Antimony to Barium

The present volume completes the description of the interactions and chemical reactions of elemental tungsten with metallic elements, treating its reactions with antimony, bismuth, and the alkali and alkaline earth metals. The reactions of tungsten with these elements are in most cases confined to surface regions. Corrosion of tungsten and mutual solubility are usually very low. An exception is the W - Be system, in which several intermetallic phases are formed. The surface processes in some of the other systems covered in the present volume evoked considerable scientific and practical interest, documented by the large number of publications. This holds particularly for the Cs-on-W and Ba-on-W surface systems. Cs- and Ba-activated tungsten electrodes were and are used in many technical and laboratory appliances. One example is the Cs diode device for thermionic energy conversion. Surface ionization of Cs and W is widely applied in ion sources and for some time attracted great attention with respect to its potential use in ion rocket propulsion engines. Cs-on-W is also a logical system for basic research on chemisorption due to the propitious chemical, crystallographic, and atomic properties of adsorbent and adsorbate. The majority of existing models for the chemisorption bond has been experimentally checked on this system. The particular interest in the W - Cs and W - Ba systems is reflected in the large portion of the text (256 pages) devoted to these systems.