Reactive flash sintering of SrFe12O19 ceramic permanent magnets

Touch‐free reactive flash sintering of dense strontium hexaferrite permanent magnet

“…It is associated with the energy stored in the magnetic field lines. This parameter, $$B{H}_{{\mathrm{max}}}\ $$= 26 kJ/m 3 , is comparable to the highest $$B{H}_{{\mathrm{max}}}$$ value obtained for pre‐aligned powders sintered by spark plasma sintering 30 and prepared by conventional RFS 15 . In order to maximize the maximum energy product in permanent magnets, it is necessary to achieve a high degree of densification while retaining significant H C and σ R .…”

“…This parameter, 𝐵𝐻 max = 26 kJ/m 3 , is comparable to the highest 𝐵𝐻 max value obtained for pre-aligned powders sintered by spark plasma sintering 30 and prepared by conventional RFS. 15 In order to maximize the maximum energy product in permanent magnets, it is necessary to achieve a high degree of densification while retaining significant 𝐻 C and 𝜎 R . In the case of ferrites, sintering process often results in the loss of their hard magnetic properties, since the sintering temperatures required to achieve optimum densification, located between 1100 • C and 1300 • C, induce massive grain growth and significant loss in 𝐻 C .…”

“…Separately, we have shown that chemical reaction and sintering in multicomponent ceramics can occur in a single step by flashing mixtures of powders of constituent oxides: so‐called reactive flash sintering (RFS) 13 . Since then, this technique has been applied to process ferrites, 14,15 ferroelectrics, 16,17 high‐entropy oxides, 18–21 and Li‐ion ceramic electrolytes 22,23 …”

“…Separately, we have shown that chemical reaction and sintering in multicomponent ceramics can occur in a single step by flashing mixtures of powders of constituent oxides: so-called reactive flash sintering (RFS). 13 Since then, this technique has been applied to process ferrites, 14,15 ferroelectrics, 16,17 high-entropy oxides, [18][19][20][21] and Li-ion ceramic electrolytes. 22,23 Here, we explore the application of the touch-free FS technique to RFS (TF-RFS), that is, preparation of multicomponent oxides by flash without the use of electrodes.…”

Rapid and controllable synthesis of LiCoO2 cathode materials by reactive flash sintering

“…This coexisting synthesis and densification sintering method is commonly referred to as reactive flash sintering (RFS) and has been reported in many studies. [21][22][23] For example, pure perovskite BiFeO 3 -BaTiO 3 ceramics could be prepared by RFS of mixed Bi 2 O 3 -Fe 2 O 3 -BaTiO 3 powders at a temperature of 858 • C under an electric field of 35 V cm −1 . 24 Through RFS, high-entropy Ca 0.2 Co 0.2 Ni 0.2 Cu 0.2 Zn 0.2 O oxide was fabricated from a mixture of CaO, NiO, CuO, ZnO, and Co 3 O 4 nano-powders under an electric field of 60 V cm −1 and current density of 300 mA mm −2 at room temperature.…”