Effects of Particle Size on Electromagnetic and Microwave Absorption Properties of La_(0.7)Sr_(0.3)MnO_(3±δ)-Epoxy Composite

摘要

La_(0.7)Sr_(0.3)Mn_(3±δ) powders were fabricated by solid-state reaction method at 1473 K for 4 h. The precursors were prepared by ball-milling raw materials for 3, 6, 9, and 12 h, respectively. The crystal structures, particle size, and morphologies of precursors and prepared La_(0.7)Sr_(0.3)Mn_(3±δ) were characterized by XRD, laser particle size analyzer and SEM, respectively. It is found that La_(0.7)Sr_(0.3)Mn_(3±δ) possessed large particle size by ball-milling raw materials for a long time. Results indicated that La_(0.7)Sr_(0.3)Mn_(3±δ), synthesized by ball-milling raw materials for 3 h, exhibited the optimal microwave absorption properties. The maximum reflection loss was -28.8 dB, and the -6 dB absorption bandwidth was 5.80 GHz.