The present study examines the structural development of ZnO nanoparticles. The coarse pure Zn powder material was melted and evaporated in an oxygen-filled chamber by renovated hybrid induction and laser heating (HILH) to produce ZnO needle-shaped nanoparticles. Simultaneously, Zn nanoparticles were also produced by HILH in an argon-filled chamber. The Zn nanoparticles were annealed in the atmosphere at temperatures of 300 degrees C, 400 degrees C, 420 degrees C and 500 degrees C, respectively, to investigate the corresponding thermal oxidation behavior. By annealing above 400 degrees C, Zn structural transformation took place, and the morphology of the nanoparticles changed to needle and/or tetrapod shape. No sintered necks between ZnO nanoparticles were found. The growth of the nanoparticles is considered to be controlled by evaporation.