Structure and properties of BaFe₁₂O₁₉ coated fly ash cenospheres by sol-gel process

Abstract

Thin films of barium hexaferrite were prepared on fly ash cenosphere particles by the sol-gel method using Fe(NO₃)₃·9H₂O, Ba(NO₃)₂ and citric acid as raw materials. The prepared films were characterized by differential thermal and thermogravimetric analysis (DTA-TG), X-ray diffractions analysis (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry. The magnetic and structural properties of barium hexaferrite coated cenosphere particles were also studied. The experimental results show that even and continual barium hexaferrite coatings were prepared on fly ash cenospheres, and the magnetic conductivity was imparted to these non-conducting oxide ceramic particles. The low density barium hexaferrite coated cenosphere particles may be utilized for manufacturing microwave absorbing materials.

Keywords

barium hexaferrite / coating / fly ash cenosphere particles / sol-gel

References

[1] He Z, Liang W, Li B. Preparation of Super Composite Cement with a Lower Clinker Content and a Larger Amount of Industrial Wastes [J]. J. Wuhan University of Technology-Mater. Sci. Ed., 2002, 17(4): 78-81.

[2] Matsunaga T, Kim J K, Hardcastle S. Crystallinity and Selected Properties of Fly Ash Particles[J]. Materials Science and Engineering, 2002, 325: 333-343.

[3] Shukla S, Seal S, Akesson J. Study of Mechanism of Electroless Copper Coating of Fly-ash Cenosphere Particles[J]. Applied Surface Science, 2001, 181: 35-50.

[4] Fang L. Synthesis and Microwave Electromagnetic Properties of M-type Hexagonal Ferrite BaTiCoFe₁₀O₁₉. J. Wuhan University of Technology-Mater. Sci. Ed., 2001, 16(3): 23-25.

[5] Shukla S, Seal S, Rahaman Z. Electroless Copper Coating of Cenospheres Using Silver Nitrate Activator[J]. Materials Letters, 2002, 57: 151-156.

[6] Yu Q, Shigeyoshi N, Lin J. Solidification of Municipal Solid Waste Incineration Fly Ash with Cement and its Leaching Behavior of Heavy Metals[J]. J. Wuhan University of Technology-Mater. Sci. Ed., 2003, 18(1): 55-61.