Synthesis, microstructures, magnetic properties and thermal stabilities of isotropic alnico ribbons

Additively Manufactured Alnico Permanent Magnet Materials—A Review

“…In another study on an Alnico alloy by Zhou et al, it was observed that although the magnetic annealing performed at 840 °C under 1 tesla(T) magnetic field increased coercivity with the increase in magnetic annealing time from 30 s to 10 min, the increase in magnetic annealing time did not change the volume fraction of the α 1 phase; the microstructural variation with magnetic annealing time is shown in Figure 18 [5,26]. However, the size and shape of the α 1 phase tend to impact the magnetic properties of Alnico, as elongated and small-diameter (high aspect ratio > 20) α 1 phase grains provide improved magnetic properties [2]. Considering this aspect, in commercial Alnico alloys, the aspect ratio of the α 1 phase is maintained in the range of 0.6-10 nm [3,7].…”

“…Alnico is a permanent magnetic material containing mainly Fe, Co, and Ni along with other alloying elements such as Al, Ti, and Cu [1,2]. The high-temperature stability (up to 400 °C) of Alnico alloys makes them suitable for replacing rare earth permanent magnets in applications such as traction motors [3].…”

“…Alnico alloys find applications in electric motors/generators, MRI machines, guitar pickups, and aviation and aerospace for navigational instruments due to their high-temperature stability [3][4][5][6]. Permanent magnets (PM) primarily consist of Alnico alloys, ferrites, and rare earth containing magnets like NdFeB and SmCo [2]. Permanent magnetic materials have high coercivity (H c ) ranging from 0.5 to 35 kOe, a remanence (B r ) of 0.7-1.5 T, and a maximum energy product (BH max ) of 0.75-54.04 [7].…”

“…On the contrary, magnetic properties of Alnico alloys are unaffected by temperature changes of up to 400 °C [18]. Alnico alloys have a curie temperature of 820-860 °C and have high temperature (>400 °C) stability, but Alnico alloys have lower coercivity (H c ) (0.5-1.89 kOe) and BH max than NdFeB [2,19,20]. Therefore, Alnico can be a potential alloy for replacing NdFeB, if the coercivity (H c ) and BH max of the alloy are improved.…”

Structure, Magnetic Properties and Magnetization Reversal Processes in Nanocrystalline Pr8Dy1Fe60Co7Mn6B14Zr1Ti3 Bulk Alloy

“…Since over than 30 years, the RE 2 Fe 14 B-type alloys (where RE= Pr, Nd, Dy or Tb) have been intensively studied due to their excellent magnetic properties. This type of alloys are used as permanent magnets in motors, as record heads, wind energy turbines and miniaturized electronic devices [1,2]. Nanocrystalline composites based on RE 2 Fe 14 B/á-Fe exhibit interaction between soft magnetic á-Fe phase and hard magnetic RE 2 Fe 14 B or pinning of domain walls, which results in higher saturation magnetization compared to single phase material based on RE 2 Fe 14 B phase [3,4].…”