Oxidation resistance and microwave absorption property of core shell urchin-like ZnO\carbonyl iron powder composite particles

In order to solve the weak oxidation resistance of carbonyl iron powder at higher temperature, carbonyl iron powders with core-shell coated ZnO were prepared using hydrothermal method and then the composites were fabricated by mixing the absorbent in the paraffin matrix. The results show that the carbonyl iron powders are coated by ZnO nano-roads, forming core-shell urchin-like composite particles. Due to this structure, the carbonyl iron powders are isolated from oxygen and thus the oxidation resistance can be improved. Compared with the absorbing materials consisting of pure carbonyl iron powders, the absorption peak for ZnO/carbonyl iron powder shifts towards the low frequency slightly, but the bandwidth of reflection loss below -5 dB is almost unchanged. The results suggest an alternative approach to improve the oxidation resistance of the carbonyl iron powders without influencing their microwave absorption properties.