Peculiarities of pulsed heating by the radiation of a subterathertz gyrotron in the production of metal oxide nanopowders

The peculiarities of the process of preparation of metal oxide nanopowders by the evaporation–condensation method with pulsed heating of the material by focused subterahertz radiation are described. It is shown experimentally that the optimal conditions for the rapid evaporation of a substance are achieved at the highest possible pulse power and the largest possible duty cycle at a fixed average power. Under these conditions, it is possible to heat and evaporate the substance with a focused radiation beam in a relatively short time, so that the adjacent layers of the evaporated substance are not warmed and fused and a relatively low thermal conductivity is maintained. A linear increase in the evaporation rate with an increase in the duty cycle of the heating pulses is revealed, and this increase reaches the fivefold value relative to the continuous heating mode.