In situ synthesis of magnetic particles on the surface of tetra-needle like ZnO whisker

Nanosized magnetic particles were synthesized in situ on the surface of tetra-needle-like ZnO whisker (ZnOw) via two steps. Firstly, the intermediate composites of polyethylene glycol (PEG), ZnOw and iron oxides were obtained through the oxidation of Fe2+ in the PEG micelles and the simultaneous adhesion of the micelles on the surface of ZnOw. Successively, the obtained semis were continuously baked in the nitrogen and hydrogen atmosphere, respectively, and ZnOw modified by magnetic particles (noted as M-ZnOw) was prepared. The as-prepared semis and M-ZnOw still kept the tetra-needle-like morphology while the magnetic particles uniformly generated on the whisker's surface, which was confirmed by the analysis of scanning electron microscopy, energy loss spectrum and X-ray diffraction. Moreover, the investigation indicated that the components of the particles formed in situ on the surface of ZnOw were influenced by the composition ratio and the experimental conditions. The investigation also suggested that PEG played a role of bridging between ZnOw and magnetic particles. Further experiments showed that M-ZnOw appeared to have good microwave absorption properties in the S-band. (c) 2005 Elsevier B.V. All rights reserved.