Evaporation and Condensation of Uranium Dioxide in an Electromagnetic Field

New physical phenomena related to the iInteraction of laser radiation with high evaporation materials, in particular with uranium dioxide, have been experimentally revealed by a subsecond heating technique. The first phenomenon, iInterpreted as an absorption flash, was observed in laser heating the sample and was manifested as a sharp drop in temperature on the heating curve. The second phenomenon, iInterpreted as a threshold condensation of vapor on the sample, was revealed during the cooling stage of the sample initially heated by laser radiation. This was manifested as an exothermal condensation peak on the cooling curve. The study of these phenomena has shown that there was a stable vapor zone above a sample in the field of laser radiation. The size and shape of the small particles produced due to laser evaporation and mainly formed in this vapor zone depended on the power of the laser radiation and the pressure of the inert gas. A change in the parameters of the vapor zone by changing the power of the laser radiation and the pressure of the inert gas gives the potential to produce nanoparticles of targeted sizes. Thus, the study of physical processes and mechanisms of forming nanoparticles of refractory materials at high temperatures motivates further development of the method of laser evaporation for producing nano-dimensional powders of targeted sizes and properties