Influence of the oxygen concentration on the formation of crystalline phases of ZrO$_2$ nanoparticles during the low-pressure arc-discharge plasma synthesis

The synthesis of nanoparticles of zirconium dioxide with different contents of the monoclinic and tetragonal phases has been investigated. The synthesis has been performed by controlling the oxygen content in the gas mixture in the plasma-chemical evaporation–condensation process in low-pressure arc-discharge plasma. The crystal structure of synthesized ZrO$_2$ nanoparticles has been studied using X-ray diffraction. The morphology of the particles has been analyzed using transmission electron microscopy. The nanoparticle growth in arc-discharge plasma has been examined using optical emission spectroscopy. The X-ray powder diffraction analysis has revealed that the content of the monoclinic phase of ZrO$_2$ increases with a decrease in the oxygen content in the oxygen–argon gas mixture.