Influence of pressure on crystal formation of zinc oxide

Сrystal formation of zinc oxide obtained by various methods of heat treatment is studied by methods of X-ray phase analysis and scanning electron microscopy. It is established that during the heat treatment of the pre-synthesized hydrozincite in air at 400 ${}^\circ$С a nanocrystalline zinc oxide is formed with an isometric shape of the particles, while during the heat treatment of the same precursor at 400 ${}^\circ$С a microcrystalline ZnO with an anisotropic form of crystalline particles is formed in a closed volume. The conclusion is drawn that conditions close to hydrothermal conditions are created in a closed volume.