Microstructure and complex magnetic permeability of thermally sprayed NiZn ferrite coatings for electromagnetic wave absorbers

Abstract

Ferrites are iron containing, non-conducting ceramics, which exhibit magnetic properties. One of the most common is (Ni,Zn) 1 Fe 2 O 4 . Bulk ferrites are typically made by conventional ceramic sintering. However, manufacture of thick coatings is of growing interest, and deposition by thermal spraying is potentially attractive. The present paper reports work on the development of (Ni 0?549 Zn 0?333 Co 0?028 Mn 0?049 )O 0?958 Fe 2 O 3 based powder feedstock by self-propagating high temperature synthesis and coating deposition by both air plasma and high velocity oxy-fuel spraying. The results obtained show that some decomposition of the ferrite material occurred with the loss of zinc and oxygen. The Zn loss is dependent to a large extent on the surface/volume ratio of the powder used in spray deposition. The influence of the spraying technique on the electromagnetic properties was also measured and compared to bulk ferrite materials. The air plasma sprayed coatings showed similar absorption coefficient compared to the bulk ferrite material at high frequencies (,3 GHz).

Study of CoFe2O4/NiFe2O4 nanocomposite ferrite film

“…Therefore, they can be used as electronic components, magnetic memories and magnetic substrates for magnetic catalysts [26]. It is reported that the exchange interaction between hard and soft magnetic phases can improve the magnetic, dielectric and microwave absorption properties [27,28]. In other words, magnetic composite ferrites with high coercivity can be used as microwave absorbing materials especially that the compound has hard and soft magnetic phases.…”

Formation of nanocrystalline FeAl2O4 matrix coating by plasma spraying

“…1 On the other hand, materials with an ultrafine structure, especially nanostructure, have been recognised to exhibit attractive physical, chemical and mechanical properties. [2][3][4][5][6] Nanostructured coatings have been considerably investigated and reported to possess superior toughness, adhesion, spallation, wear, corrosion and thermal resistance compared to their conventional coarse grained counterparts. [7][8][9][10] Several fabrication routes are under development to produce nanostructured coatings.…”

Amino surface modification of Fe3O4/SiO2 nanoparticles for bioengineering applications

“…[1][2][3][4][5][6][7] Studies of iron based materials have attracted much interest in the last few years from both fundamental and applicative points of view. [8][9][10][11][12][13] Surface modification of magnetic nanoparticles (NPs) is a frequently used method to promote the performance of NPs as nanobiomaterials. In the recent decades, magnetic NPs, especially Fe 3 O 4 and c-Fe 2 O 3 , have attracted increasing interest because of their outstanding properties, including superparamagnetism and low toxicity and, as a result, their potential applications in various fields, especially in biotechnology and biomedicine, such as cell sorting, enzyme immobilisation, biosensing and bioelectrocatalysis, separation and purification.…”