Gas-surface interfacial and gas-phase resistances to vaporizing cesium hydroxide and chloride in air

• Theoretical concept of the mass transfer resistance to vaporizing species was established.
• The resistances in a series that limit the transport of semi-volatile cesium species in air were evaluated.
• Gas-phase resistances were at least a hundred times greater than interfacial resistances.

The interfacial and the pure gas-phase resistances in air to vaporizing cesium species were evaluated in a comparison of the experimental vaporization flux and the maximum vaporization flux as calculated based on the kinetic theory of gas and the film theory. Gas-phase mass transfer resistances did not show great changes with the temperature, but their values were much greater that those associated with the interfacial resistances. The values of gas-phase resistances were at least a hundred times greater than interfacial resistances for the vaporizing cesium species investigated in this study.