Preparation of Magnetic Expanded Graphite by Sol-Gel Method and its Electromagnetic Properties
In order to transform the diamagnetism of expanded graphite (EG) to ferrimagnetism and improve its electromagnetic interferential capability, nano γ-Fe2O3/EG magnetic composite materials was prepared by sol-gel and low temperature self-combustion technique. The as prepared samples were characterized by SEM, XRD and Magnetic hysteresis cycle test. The results indicated that the composite materials had ferrimagnetism property after the embedding of γ-Fe2O3, but the average conductivity of the composites decreases gradually with the increase of γ-Fe2O3. Different mixing ratio of ferrite gel and graphite intercalation compounds produced ferric oxide with different crystal form and shape. When the content of ferrite sol was low, spherical γ-Fe2O3 with the mean size of 31.69nm was formed, and spread unevenly on the surface and interformational micelles of EG. High content of ferrite sol (83wt%) produced more perfect crystal γ-Fe2O3 of pentahedron shape with the mean size of 44.68nm, and a few of α-Fe2O3 occurred which lead to the decline of the magnetic property of the composite materials.
Pengcheng Wang, Liqun Ai, Yungang Li, Xiaoming Sang and Jinglong Bu
Q. Zhang et al., "Preparation of Magnetic Expanded Graphite by Sol-Gel Method and its Electromagnetic Properties", Advanced Materials Research, Vols. 295-297, pp. 93-97, 2011