Hollow γ-MnO₂ sphere was obtained by annealing the precursor at 400 °C with different holding time. The influences of different holding time on the morphology and crystalline structure of final products have been discussed in detail, and the microwave absorption properties of the as-products were also investigated. The results exhibited that finer crystalline feature of the γ-MnO₂ and larger pore size in the hollow γ-MnO₂ sphere could be obtained with the extended holding time. The MnO₂/paraffin composites (50 wt% loading) present extraordinary microwave absorption performance, and the minimum reflection loss (RL) values is −51.3 dB at 4.9 GHz with the thickness of 3.5 mm. The excellent electromagnetic absorption properties can be ascribed to the hollow structure, perfect impedance matching behavior and the multiple interface polarization effect.

中空γ-MnO的₂通过用不同的保持时间进行退火，在400℃的前体获得的球体。详细讨论了不同保温时间对最终产物的形态和晶体结构的影响，并研究了副产物的微波吸收特性。结果表现出的γ-MnO的的更精细的结晶特征₂在中空γ-MnO和较大的孔径₂可以与扩展保持时间来获得球体。MnO ₂/石蜡复合材料（50 wt％的负载量）具有出色的微波吸收性能，在4.9 GHz厚度为3.5 mm的情况下，最小反射损耗（RL）值为-51.3 dB。优异的电磁吸收性能可归因于中空结构，完美的阻抗匹配行为和多界面极化效应。