摘要
The phase transition process of the MnO2 phase with increases in Co^2+doping can be described by the Ouroboros symbol.The undoped sample is pureδ-MnO2 with nanosheets structures.Then a small amount of Co^2+ions changes the final products and generatesα-MnO2 nanofibres in theδ-MnO2 matrix.The products become pureα-MnO2 with an appropriate amount of Co added.However,when the Co amount continues to increase,the amount ofα-MnO2 decreases in the products and turns back to form pureδ-MnO2 in the end.Analysing the electromagnetic absorption performance,the relationship between the properties and the proportion ofδ-MnO2/α-MnO2 in the powders adjusted by Co^2+doping has been explored,and the composites ofδ-/α-MnO2 show better absorption ability than the single-phase samples.As a result,the optimal reflection loss(RL)is−54.8 dB,and the effective absorption bandwidth can cover the Ku band at a thickness of 2.2 mm and the X band at a thickness of 3.1 mm with 50 wt.%filler loading ratios.This research might shed new light on the improvement of novel microwave absorption materials.
基金
the Support by Program for the National Natural Science Foundation of China(Nos.51577021 and U1704253)
the Fundamental Research Funds for the Central Universities(No.DUT17GF107).
作者简介
Address Correspondence to:Yuping Duan,duanyp@dlur.edu.cn;Address Correspondence to:Huifang Pang,huifangpang@dlut.edu.cn。
