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发布时间：2019-03-09

论文类型：期刊论文

发表时间：2013-01-01

发表刊物：PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART L-JOURNAL OF MATERIALS-DESIGN AND APPLICATIONS

收录刊物：Scopus、EI、SCIE

卷号：227

期号：L1

页面范围：61-69

ISSN号：1464-4207

关键字：MnO2; annealing treatment; microwave absorption

摘要：Chemically synthesized alpha-MnO2 powder was annealed at different temperatures with (NH4)(2)S2O8 as the oxidant and MnSO4 as the manganese source. The obtained samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and vector network analysis. Results indicated that the structures and morphologies of the products did not change remarkably, mainly consisting of alpha-MnO2 with a sea urchin-like shape, when the annealing temperature was below 500 degrees C. However, it was observed that the powder changed from alpha-MnO2 to Mn2O3 at 500 degrees C and 600 degrees C. The scanning electron microscopy images showed that the morphologies of the resulted Mn2O3 powder were microspheres in various sizes. Microwave absorption properties of the as-synthesized samples were also discussed, which showed that the dielectric loss tangent, magnetic loss tangent and reflection loss could be improved significantly by increasing the annealing temperature appropriately (<500 degrees C).