Behaviour of carbon on tungsten monocrystal (110) and (112) faces when simulating interaction with thermionic converter interelectrode medium

The behavior of carbon on (110) and (112) W faces has been studied in the context of simulating thermal vacuum preparation of a thermionic converter emitter that can be contaminated by ≈0.015 at.% carbon contained in the bulk of the material and when interacting with hydrocarbon contained in the residual gas medium. At T≈400 K carbon exists on the surface in the graphite state. As T rises to ≈900 K the buildup of carbide is initiated. A mixed carbide-graphite state on the surface is possible in the range 600-900 K