The sintering characteristics of pure tetrapod ZnO nanopowders prepared by thermal evaporation deposition (TED)

The sintering characteristics of pure tetrapod ZnO nanopowders prepared by thermal evaporation deposition (TED) were studied in this paper. The results imply that there exist large amounts of interstitial zinc in the grains and much adsorbed oxygen on the surface. Even though the sintering temperature is low to about 500 °C, the pure tetrapod ZnO nanopowders grow sharply and reach about 280 nm. Using the expression of Gn−G0n=Ktexp(−Q/RT), the results of the kinetic grain growth study show that the kinetic grain growth exponent n is about 2.2. As for the grain growth activation energy Q, it is found that when the sintering temperature is lower than 900 °C, the activation energy is about 57.1 kJ/mol, and consequently increases up to 147.9 kJ/mol at the temperature higher than 900 °C. The growth mechanisms are discussed.