Development of Ba-hexaferrite coatings for electromagnetic wave absorption applications

Thermal Spray Coatings for Electromagnetic Wave Absorption and Interference Shielding: A Review and Future Challenges

“…There are obvious limitations in the possibility to adjust them to the various shapes of components requiring EM protection: these limitations can be overcome by the application of thermal spraying technologies. In a work by Bobzin et al (2010), [ 86 ] Ba–hexaferrite coatings for EM mm‐wave absorption applications were deposited by APS. A suitable powder feedstock was manufactured by blending a BaCO 3 + Fe 2 O 3 mixture, which was then agglomerated by spray drying.…”

Improving the stoichiometry of RF-sputtered amorphous alumina thin films by thermal annealing

“…Few of these works however have investigated the optical properties of amorphousa lumina films, and fewer have paid attention to how stoichiometry affects the optical behaviour. Alumina is the onlys table oxide of aluminium (Al) [33], and thus in the absence of an atom of any other element, ac hemical combination of Al and oxygen (O) would always give alumina (which may be amorphous or any of the known crystal phases dependingontemperature of formation [1][2][3][4][5][6][7][8][9]). Although, non-stoichiometry of alumina film could be deliberate and desirable in someapplications [34 -38], it should however be noted that excess of eitherA lo rO(non-stoichiometry) in Al 2 O 3 constitutes an impurity and can impact on the films' properties.…”

Characterisation of plasma-sprayed SrFe12O19 coatings for electromagnetic wave absorption

“…On the one hand, the spray parameters and the size distribution of the feedstock powder have to be optimised in order to embed a controlled fraction of unmelted material in the sprayed layer while retaining sufficient deposition efficiency 22,23 ; specifically, the best results were obtained using the APS technique. 22 On the other hand, the production route of the feedstock powder also plays a crucial role.…”

“…The resulting APS coatings contained crystalline hexaferrite both in the porous unmelted regions and in the dense ones. 23 The aim of the present research is therefore to study the deposition of SrFe 12 O 19 (Sr-hexaferrite) coatings by APS using both spray-dried agglomerates of micrometric Sr-hexaferrite particles and reactively sintered agglomerates. Particularly, the paper focuses on the different microstructures and phase distributions within the coatings obtained by using these two kinds of feedstock, investigated by SEM, XRD and micro-Raman spectroscopy.…”