Abstract: The kinetics of oxidizing zinc vapor in different atmospheres at an elevated temperature was determined by thermogravimetric analysis and the morphologies of products were examined by scanning electron microscopy. The results showed that the product morphologies were of amorphous, granular, needle-like ZnO when the kinetics progressed linearly and the morphologies of tetrapod and/or multipod-like ZnO appeared as the kinetics proceeded parabolically. The cause of the kinetics change was the coexistence of atomized zinc and tiny zinc droplets formed in zinc vapor under proper conditions. The kinetics advanced linearly as the atomized zinc was oxidized while the kinetics followed the interface reaction R₃ and Ginstling-Brounstein D₄ model with apparent activation energy of 10⁶.3₁08.2 kJ/mol and 114.2-117.3 kJ/mol respectively in the early and later stages of the zinc droplets oxidation. The oxidation process of the tiny zinc droplets is controlled by the outward diffusion of Zn through the oxidation scale and the diffusion coefficient D=2.46×10^-5-9.70×10^-5 cm²/s.

Key words: Zinc vapor, Zinc droplets, Oxidation behavior, ZnO crystalline morphologies