Temperature-and field-induced changes in the form of the Mo-Hf alloy

Abstract

Simultaneous action of strong electric fields and high temperatures on point field emitters made of the Mo-15%Hf alloy is studied by field emission methods. Such alloys enriched with an emission-active component and containing the Mo2Hf intermetallide exhibit basically the same stages of temperature-and field-induced changes in their form as for pure metals, although a number of peculiarities associated with the surface segregation of Hf also exist. Thermal-field processing of emitters was accompanied with high-temperature field evaporation and emission of predominantly Hf (both atomic and cluster-type) ions. Thermal-field processing also enhances emission localization, but to a smaller extent as compared to that in alloys with a low Hf concentration.