The synthesis and characterization of nickel and cobalt ferrite nanopowders obtained by different methods

I Zalite,G Heidemane,M Maiorov,J Grabis,L Kuznetsova,M Kodols

doi:10.5755/j01.ct.67.1.15824

Abstract

The ferrite materials, especially of nickel and cobalt, are popular due to their unique mechanical and magnetic properties. The single phase NiFe2O4 and CoFe2O4 ferrites were synthesized by three methods: the high frequency plasma chemical synthesis, the sol-gel self-combustion, and the co-precipitation technology combined with the hydrothermal synthesis method. Magnetic properties, crystallite size, the specific surface area of synthesized products are characterized. Nanopowders synthesized in the high frequency plasma have a specific surface area in the range of 28–30 m2/g (the average particle size 38–40 nm, crystallite size ~40 nm), but a wider particle size distribution is in the range of 10–100 nm with some particles of 200 nm. The ferrite nanopowders obtained by the sol-gel self-combustion and hydrothermal synthesis method have the specific surface area of 40 ± 3 and 60 ± 5 m2/g (average particle size 25–30 nm and 19–26 nm, crystallite size 10–20 nm and 12–20 nm), respectively. Cobalt ferrites after synthesis are characterized by the saturation magnetization MS of 75 emu/g (for plasma chemical synthesis), 53 emu/g (for the self-combustion method), and 57 emu/g (hydrothermal synthesis). The saturation magnetization for nickel ferrites is 44, 29 and 30 emu/g, respectively. After the thermal treatment up to 900 oC the particle size of all ferrites increases, but their magnetic properties are approaching those of monolithic ferrites.DOI: http://dx.doi.org/10.5755/j01.ct.67.1.15824

Highlights

Ferrites are a wide range of minerals and synthetic materials, which have attracted a wide range of scientists’ interest due to their various applications
It has been found that all synthesized ferrites, with the exception of the spray-drying method, are nanocrystalline stoichiometric single-phase powders (Figure 1) with a specific surface area (SSA) in the wide range of 30–55 m2/g depending on the synthesis method and calculated particle size of 20–40 nm (Table 1, Figure 2)
Single-phase nickel and cobalt ferrite nanopowders can be successfully synthesized by the chemical sol-gel self-propagating combustion and co-precipitation method combined with hydrothermal synthesis or spray-drying method as well as high-frequency plasma synthesis

Summary

Introduction

Ferrites are a wide range of minerals and synthetic materials, which have attracted a wide range of scientists’ interest due to their various applications. 98 Powder Technology materials due to their unique electrical, dielectric, electronic, mechanical, magnetic, optical and catalytic properties These ferrites are characterized by good magnetic properties [1], low (NiFe2O4) [2] or high (CoFe2O4) [3] magnetic coercivity, high electrical resistivity and negligible eddy current loss for high-frequency electromagnetic wave propagation [2], chemical stability and fairly high mechanical hardness [4], low dielectric losses and high Curie temperature [5]. Scientific articles contain extensive information on hyperthermia This method introduces ferrite nanoparticles into living organisms and, under controlled conditions, nanoparticles are transported to the cancerous areas of the body, and cancer cells are destroyed in a magnetic field by heat treatment [10]

Methods

Results

Conclusion