Hydrogen Adsorption on (110) Tungsten at 30 K: an Atom-Probe Field-Ion Microscope Study

摘要

Adsorption of hydrogen on (110) oriented tungsten specimens has been studied via field desorption in an atom-probe field-ion microscope. Adsorption was studied on surfaces prepared by field evaporation. Typically, hydrogen field desorption events were exhausted after seven tungsten (110) planes had been field evaporated. Exposures were controlled by applying a potential to the specimen which was sufficient to field ionize hydrogen gas molecules approaching the specimen and which thereby prevented additional hydrogen from being adsorbed. An adsorption model which invokes sticking at step sites but not at plane sites is proposed to explain the coverage data. (ERA citation 09:040500)