Synthesis of ZnO fibers and nanometer powders by hydrothermal method

A new hydrothermal process-hydrothermal salt solution pressure-relief-was introduced, and ZnO powder with the size of 15 nm and ZnO fiber with length/diameter = 16:1 were prepared by this process. The change of particle size of ZnO powder and the formation mechanism of ZnO fiber were investigated. It is proposed that the main factor affecting the particle size of powders is nucleation rate, that is, the bigger the nucleation rate is, the smaller the particle is; the main factors affecting the formation of fiber include whether hydrothermal reaction proceeds under the condition of pressure-relief or not and the crystallization degree of powders before pressure-relief.