Increase In Coercivity Research Articles

Volume effects on microstructures and magnetic properties of MnGa thin films during order-disorder transformation

In this study, L10 MnGa thin films were grown on an amorphous glass substrate, and the relationship between the volume effect and the magnetic properties of thin films as a function of the film thickness was investigated. An amorphous thin film and weak magnetic properties were observed at the thickness of 10 nm. With the increase in thickness, the magnetization (M10 kOe) and coercivity (Hc⊥) also increased. The maximum M10 kOe and Hc⊥ values were 106.3 ± 5.7 emu/cm3 and 8.54 kOe in a 200 nm-thick sample, respectively. X-ray diffraction indicated that the order-disorder transformation occurred when the thickness was greater than 25 nm. Plan-view transition electron microscopy (TEM) images indicated the emergence of larger grains and blurred grain boundaries when the thickness was increased beyond 25 nm, while cross-sectional TEM images suggested that the appearance of nuclei promote the growth of columnar MnGa grain structures. Energy dispersion spectroscopy analysis indicated that the composition of MnGa was Mn-rich (or Ga-poor) in the nuclei at the initial growth state and then gradually changed to Mn50Ga50 as the thickness increased. In addition, the effects of the base pressure of the chamber on the phase and magnetic properties of the MnGa films were also investigated.

Green synthesis based X-type Ba–Zn Hexaferrites: Their structural, Hysteresis, Mӧssbauer, dielectric and electrical properties

Ba2Zn2Fe28O46 hexaferrite was prepared using green synthesis with different quantities of ginger root extract (obtained from 0.0, 17.5, 35, 52.5 and 70 g of ginger root) as a natural antioxidant reducing agent. The dried precipitates were preheated at 550 °C/4 h and finally heated at 1200 °C/5 h. The effect of ginger root extract on structural, phase purity, magnetic, Mӧssbauer and low frequency (10 Hz–2 MHz) dielectric properties were investigated. XRD analysis of samples prepared with extracts from 35, 52.5, and 70 g of ginger depicted pure X-phase, while the other samples (0.0, 17.5 g) showed the secondary phase of M-type (BaM, BaFe12O19) along with hematite (12% α-Fe2O3). Hence, samples with greater amounts of ginger extract formed single-phase X-type hexaferrite. Saturation magnetization (MS) varied from 40.8 A m2/kg without ginger extract to 69.8 A m2/kg with extract from 52.5 g ginger, and was <65 A m2/kg for all samples made with the ginger extract. All synthesized samples were relatively soft ferrites, and coercivity increased with amount of ginger extract used. The Mӧssbauer spectra explored six sextets of five magnetic sub-lattices, and the presence of Fe3+ (99.4–97.3 %) and Fe2+ (0.6–2.7 %) ions, with more Fe2+ present in the extract-derived samples. The variations in MS based on hysteresis loops were in agreement by Mössbauer spectroscopy. The use of the extract also significantly reduced the grain size, from 3.3 μm without ginger extract to 0.7–1.7 μm with the extract, with a corresponding increase in coercivity from 16 to 40–80 kA/m. The samples prepared with extracts from 35 g to 52.5 g ginger root possessed considerable real dielectric constant compared to the others, but the extract also increased conductivity in the high-frequency region. Complex impedance displayed low values in the high-frequency region, and Cole-Cole plots revealed that the main contribution to conductivity in extract-based samples was from the grains. The reducing action of the green extract not only produced single phase X ferrite, but it also reduced grain size to ∿1–2 μm and greatly increased MS.

Coercivity engineering in Sm(Fe0.8Co0.2)12B0.5 thin films by Si grain boundary diffusion

Achieving a large coercivity in the SmFe12-based compounds with excellent intrinsic magnetic properties is the main challenge toward the development of new high-performance permanent magnets. In this study, we investigated the effect of microstructural factors on coercivity using Sm(Fe0.8Co0.2)12B0.5 thin films as a model system. The films were composed of columnar Sm(Fe0.8Co0.2)12 grains with [001] out-of-plane texture separated by ∼5 nm-thick (Fe,B)-rich amorphous intergranular phase. To decrease the Fe content in the intergranular phase and improve the magnetic isolation of Sm(Fe0.8Co0.2)12 grains, grain boundary diffusion of Si was performed, which led to an increase in coercivity from 1.11 T to a record high value of 1.32 T for the Sm(Fe0.8Co0.2)12 compound. Detailed microstructure characterization using scanning transmission electron microscopy (STEM) and atom probe tomography (APT) confirmed that Si diffused in-part into the intergranular phase which became depleted of Fe and Co. Micromagnetic simulations on a model constructed based on STEM images have shown that triple junctions of the intergranular phase can act as nucleation centers during demagnetization process. This detrimental effect can be suppressed by full-depth diffusion of Si weakening the ferromagnetism of the intergranular phase. However, the presence of α-(Fe,Co) grains at the interface with a V underlayer substantially reduces the benefits of grain boundary diffusion. Thus, high coercivity in the SmFe12-type magnets cannot be obtained unless the soft magnetic α-(Fe,Co) phases are eliminated.

Cd-substituted NiZnCo ferrite with high dielectric constant and low coercivity for high-frequency electronic devices

This work investigated the effect of replacing Zn 2+ ions with Cd 2+ ions on the microstructure and electromagnetic properties of NiZnCo ferrites. The studies show that the Cd 2+ ions substituted for Zn 2+ ions at the A sites (tetrahedral sites) of the ferrite lattice. The large ionic radius of the Cd 2+ ions can cause lattice distortion. Concurrently, the low melting point of CdO can effectively reduce the sintering temperature of NiZnCo ferrite, thereby significantly changing the magnetoelectric properties of NiZnCo ferrite. These changes are mainly manifested as the decrease in the saturation magnetization ( M s) from 66.6 to 58.5 emu/g and the increase in coercivity ( H c) from 31.2 to 34.8 Oe. The dielectric constant increases considerably, dielectric loss tanδ gradually decreases from 4.71 to 0.83 at 10 kHz, and DC resistivity ρ decreases considerably from 8.0 × 10 4 to 1.61 × 10 4 Ω m. Therefore, the substitution of Cd 2+ ions in NiZnCo ferrite provides excellent electrical and magnetic properties, which provide a reference for the development of high-frequency miniaturized electronic equipment.

Anomalous Hall effect and anisotropic magnetoresistance of molecular beam epitaxy grown Cr2Te3 thin films

High-quality Cr2Te3 epitaxial thin films with thicknesses ranging from 2.5 to 30 nm have been epitaxially grown on SrTiO3(111) single-crystal substrates using molecular beam epitaxy. The optimal growth temperature of the films was found to be 275 °C. All Cr2Te3 films show semiconductor-to-metal transition which is coupled with the paramagnetic-to-ferromagnetic transition at TC = 175 K. Consequently, all Cr2Te3 films show negative magnetoresistance effect which is strongest near TC and can be understood within the framework of electronic phase separation scenario. Both anomalous Hall effect and out-of-plane magnetic hysteresis loops show that all Cr2Te3 films have perpendicular magnetic anisotropy with the easy magnetization axis along the c-axis of the films. With decreasing film thickness the coercivity increases and reaches 10 kOe for the thinnest 2.5-nm film. Magnetoresistance measurements at different angles between the direction of the magnetic field and the easy magnetization axis reveal that Cr2Te3 films show anisotropic magnetoresistance whose out-of-plane values are larger than those of in-plane ones.

Experimental evidence for the suitability of the hydrogen decomposition process for the recycling of Nd-Fe-B sintered magnets

An effective and complete processing route for the recycling of sintered Nd-Fe-B scrap magnets was proposed. Sintered Nd-Fe-B magnets were subjected to the Hydrogen Decrepitation (HD) process at various temperatures in the range of 50–300 °C, at two different pressures, 50 kPa and 200 kPa, followed by vacuum dehydrogenation in the range of 720–820 °C. The structure refinement efficiency and magnetic properties of the powders obtained were characterized. Low hydrogen pressure (50 kPa) was found to increase the magnetic properties at each temperature for all powder fractions. It was also shown that particle refinement occurs at low (50 °C, 100 °C) temperatures for low (50 kPa) pressure and higher temperatures (200 °C, 300 °C) for high pressure (200 kPa), respectively. High pressure also accelerates the initialization of the HD process at each temperature. No correlation was found between hydrogenation temperature and magnetic properties of the powders, except for the small increase in coercivity increase with growing temperature. The coarse fraction (400–500 µm) was found to have the highest magnetic properties for almost each HD process. The best magnetic properties Hci = 497 kA/m, Br = 1.1 T, and (BH)max = 121 kJ/m3 were obtained for hydrogenation at a temperature of 50 °C, pressure 50 kPa and dehydrogenation at 780 °C.

Effect of Dy3+ substitution on microwave behaviour of nanocrystalline Mn-Zn Ferrite

Microwave-hydrothermal (M-H) method had been employed to synthesize a series of Dy3+doped Mn-Zn ferrite Mn0.6Zn0.4Fe2–xDyxO4 (x=0, 0.01, 0.03, 0.05, 0.07, 0.09) nanopowders at 160°C/30 min. The prepared samples have been characterized by Fourier Transform Infrared Spectrometer. The grain size of sintered ferrites are in the range of 60-70 nm. Decrease in saturation magnetization and increase in coercivity were observed with an increase of Dy3+ concentration in Mn-Zn ferrites. The complex permeability and complex permittivity of the prepared samples were measured in the frequency range of 2–18 GHz using a using a vector network analyzer. It is observed that small variation of Dy3+ substitution in spinel ferrite tailored microwave absorbing parameters dramatically. The reflection loss (RL) increased with the Dy3+ content upto x ≤ 0.03. The sample with x=0.03 of thickness 2.3 mm showed minimum reflection loss of -20.5 dB with a bandwidth of 3.8 GHz. Thus the present materials exhibit good microwave absorption properties and hence can act as EMI suppressors. Copyright © 2018 VBRI Press.

Structural, optical, dielectric, and magnetic properties of Sr0.7La0.3Zn0.3Fe11.7–xAlxO19 hexaferrite synthesized by the solid-state reaction method

M-type Sr0.7La0.3Zn0.3Fe11.7–xAlxO19 hexaferrites were prepared using the conventional solid state reaction method in 1240 ​°C. XRD spectras indicated that there was a single magnetoplumbite phase with no detection of other phases for all samples. FT-IR and Raman spectra proves the formation of lattice and structure of M-type hexagonal ferrite respectively, and by the shift of the peaks, we speculate that Al3+ entered the lattice. FE-SEM micrographs showed that the grains were platelet-like shapes, EDS indicates that all elements are predetermined and no other elements are produced. The impedance analyzer found that all the dielectric parameters were optimized in different degrees under the corresponding doping amount, and the change was consistent with the characteristics of hexagonal ferrite magnetic materials. VSM finds that HC increased rapidly to a maximum value of 4576.8 ​Oe at x ​= ​1.5, which was ∼96.4% increase in coercivity as compared to that of Sr0.7La0.3Zn0.3AlxFe11.7-xO19 at x ​= ​0.0.

Simultaneous increase in remanence and coercivity during grain refining of Nd-Fe-B deformed magnets

To explore the feasibility of deep grain-size refinement in overcoming the problem of traditional Br-Hci trade-off in bulk permanent magnets, the effect of deformation temperature on the texture strength, grain refining, and magnetic properties of slow-deformed Nd-Fe-B magnets was systematically studied. As a result, strong textures with gradual grain refining from conventionally large size of DL = 650 nm to small nanoscale size of DL = 53 nm (DL denotes the lateral size of the aligned plate-like grains) are observed as the temperature reduces from Td = 650 °C to Td = 450 °C. Moreover, magnetic observations show a simultaneous increase in remanence and coercivity as the grain refines from DL = 650 nm to DL = 127 nm. The increase in coercivity results from the grain size refinement as well as the smaller aspect ratio of the plate-like grains, and the increase in remanence results from the improved texture homogeneity. As compared with the DL = 650 nm magnets, the simultaneous increase in remanence and coercivity leads to optimum enhancements of 57% in coercivity, 10% in remanence, and 25% in energy product, which demonstrate the feasibility of near-nanoscale grain refinement in overcoming the traditional Br-Hci trade-off for improved (BH)max values. The failure of higher coercivities in the DL ≤ 80 nm magnets is closely related with the defect effects of the grain boundaries. Mechanisms explaining the grain refining and texture changing behavior were also discussed.

Enormous improvement of the coercivity of Ga and Cu co-doping Nd-Fe-B sintered magnet by post-sinter annealing

Post-sinter annealing is essential to improve the microstructures and magnetic properties in NdFeB-based sintered permanent magnetic materials. In this paper, investigated systemically are the effects of post-sinter annealing on the microstructures and magnetic performance of Ga and Cu co-doping Nd2Fe14B based sintered magnets. It is found out that the intrinsic coercive force of the magnets increased from 9.17 kOe to 18.67 kOe after two stage post-sinter annealing (PSA), which shows an extraordinary increment of 103.5%. The remanence, with a decreasing percentage of 1.95%, slightly decreases from 13.87 kGs to 13.60 kGs. The substantial increase of intrinsic coercivity is mainly attributed to the improvement of clean and thin continuous grain boundary layers, the smoothness of hard magnetic matrix phase and the appearance of the RE6(Fe, M)14 antiferromagnetic phase during annealing. The reduction of the remanence is caused by the deteriorated orientation degree and reduced volume fraction of hard magnetic main phases after post-sinter annealing.

Structure and Magnetization of Strontium Hexaferrite (SrFe12O19) Films Prepared by Pulsed Laser Deposition

M-type strontium hexaferrite (SrM) thin films show excellent magnetic properties and uniaxial magnetic anisotropy. We systematically investigated the magnetism of SrM films prepared by pulsed-laser deposition on different substrates [Al2O3 (11¯02), SrTiO3 (100), ZnO (0001), and LiNbO3 (0001)] at vacuum (10−4 Pa) and a substrate temperature of 800°C. Prepared films were annealed in air at a temperature of 1,000°C for 2 hours. This investigation determined the effect of annealing and different substrates on the morphology, strain, and hysteresis loops of the films. The prepared films were characterized using x-ray diffractometry, Raman spectroscopy, scanning electron microscopy, and superconducting quantum interference device (SQUID) magnetometry. X-ray diffraction analyses confirmed c-oriented growth along the out-of-plane direction in most films. We found that annealing causes enhanced crystallization in films and a significant increase in coercivity. The highest coercivity of ∼11 KOe was measured for the film deposited on the Al2O3 (11¯02) substrate.

Influence of post‐synthesis NaCl flux treatment on the magnetic properties of jet‐milled SrFe12O19 powders

AbstractA post‐synthesis NaCl flux treatment was carried out on jet‐milled strontium hexaferrite, SrFe12O19 powders prepared by conventional high‐temperature solidstate reaction starting from SrCO3 and Fe2O3. Microstructural studies reveal that the adverse effects of jet‐milling on the particle morphology like jagged edges and ruptured surfaces have been effectively mitigated by annealing at elevated temperatures in the presence of molten NaCl flux. The coercivity values obtained from angle‐dependent M versus H measurements revealed that the coercivity mechanism in the jet‐milled powders is dominated by reverse nucleation due to the strain induced during milling. Annealing the powders in presence of NaCl flux changes the coercivity mechanism to exclusively domain rotation. This results in a dramatic increase of coercivity from 1.6 kOe for the jet‐milled powders to a maximum of 5.3 kOe for the flux‐annealed powders. XPS studies show that the NaCl flux treatment has not altered the chemical state of Fe.

Formation of L10-FeNi hard magnetic material from FeNi-based amorphous alloys

L10-FeNi hard magnetic alloy with coercivity reaching 861 Oe was synthesized through annealing Fe42Ni41.3Si8B4P4Cu0.7 amorphous alloy, and the L10-FeNi formation mechanism has been studied. It is found the L10-FeNi in annealed samples at 400 °C mainly originated from the residual amorphous phase during the second stage of crystallization which could take place over 60 °C lower than the measured onset temperature of the second stage with a 5 °C/min heating rate. Annealing at 400 °C after fully crystallization still caused a slight increase of coercivity, which was probably contributed by the limited transformation from other high temperature crystalline phases towards L10 phase, or the removal of B from L10 lattice and improvement of the ordering quality of L10 phase due to the reduced temperature from 520 °C to 400 °C. The first stage of crystallization has hardly direct contribution to L10-FeNi formation. Ab initio simulations show that the addition of Si or Co in L10-FeNi has the effect of enhancing the thermal stability of L10 phase without seriously deteriorating its magnetic hardness. The non-monotonic feature of direction dependent coercivity in ribbon segments resulted from the combination of domain wall pinning and demagnetization effects. The approaches of synthesizing L10-FeNi magnets by adding Si or Co and decreasing the onset crystallization temperature have been discussed in detail.

Application direction of amorphous and nanocrystalline alloy materials and the evaluation of venture capital value

At present, the country vigorously calls for the use of green, energy-saving and environmentally friendly materials in various fields, especially in electronic power systems that require the use of low-loss soft magnetic alloy materials. Amorphous nanocrystalline alloy materials that have received widespread attention have excellent high magnetic permeability and low loss performance. Therefore, this material has become a power system with energy saving, environmental protection and excellent efficiency. Among them, soft magnetic alloys have the most application prospects. In this paper, various amorphous/nanocrystalline samples have been successfully prepared by vacuum arc melting and rapid cooling. Using XRD, HV and SEM testing and analysis methods, the structure, hardness, mechanical properties, magnetic properties and other alloys were successfully prepared. Mo element improves the ability to form glass from amorphous nanocrystalline alloys, the alloy with alloy composition has the best glass forming ability. The addition of Mo deteriorates the soft magnetic properties of the alloy. The saturation magnetic flux density Ms of the alloy is reduced from 81 to 59 emu/g, but the coercive force is not significantly improved. By increasing the Fe content, the amorphous forming ability and heat the stability decreases, the Vickers hardness and corrosion resistance decrease, and the saturation magnetization and coercivity increase. It can reduce the cost of the alloy and improve the magnetic properties of the alloy.

Static magnetic, complex dielectric and complex permeability properties of aluminum substituted hexagonal barium ferrites based on doping concentration

The regulation of magnetic and dielectric properties for hexagonal barium ferrites by ion doping is highly desirable in magnetic recording and microwave absorption. Herein, aluminum (Al)-substituted barium hexaferrite with the general formula of BaFe12−xAlxO19 (x: 0, 0.6, 1,2, 1.8) was obtained. The influences of the Al3+ doping concentration on the crystal structure, microstructure, static magnetic, complex dielectric and permeability properties of hexagonal barium ferrites were studied. The morphologies and crystal structure characterizations confirm the Al3+ ion has effective doping in the hexagonal barium ferrites and substituted for Fe3+ in positions of 2b site. The lattice parameters and grain size of the hexagonal barium ferrites were dependent on the doping concentration. The magnetic characterization displays the saturation magnetization decrease while the coercivity increase with the doping concentration. The high-value about 8249 Oe of coercivity can be obtained at x = 1.8. The dielectric properties measurement further indicates that Al doping could improve both real and imaginary parts of permittivity. The highest value of the real part of permittivity was obtained at x = 1.2. Lastly, the complex permeability spectrum displayed the doping of Al ions not only regulate the complex permeability but also influence the domain wall resonance frequency, which is significant for controlling the application frequency.

Tremendous enhancement of magnetic performance for Sm(CoFeCuZr)z magnet based on multiscale copper redistribution

Microstructure and magnetic properties were studied for the commercial Sm(CoFeCuZr)z magnets before and after post annealing treatment. The results show that the phases composition and orientation of the magnet do not change after post annealing treatment, but the substantial redistribution of Cu element within multiscale (the microscale crystal grain and the nanoscale cellular structure) is observed simultaneously. In detail, along with the Cu redistribution, the thickness of the Cu-rich Sm(Co,Cu)5 cell boundary becomes thinner, and the Cu concentration in the boundary increases sharply. The pinning field of domain walls and corresponding coercivity increase remarkably with slight remanence and maximum energy product loss, and the overall magnetic performance of (BH)max (MGOe)+Hcj (kOe) increases by 54.3% as a result. Moreover, the thermal stability of the magnet improves as well. On the other hand, Cu-lean phenomenon was observed along the grain boundary region, triggering to magnetic domain reversal process and slightly undermining the squareness of the demagnetization curve of the magnet.

Investigation of structural, magnetic and electronic properties of FeTa films for varying Ta concentration at different annealing temperatures

In the present work, temperature dependent magnetic, structural and electronic properties of FeTa films with increasing Ta concentration are investigated. X-ray reflectivity (XRR) studies reveal densification of the film with increasing Ta concentration. Thermal annealing also results in an increased electron density relative to as-deposited film, concurrent with increase in grain size as observed from X-ray diffraction (XRD) and results of Soft-X-ray absorption spectroscopy (SXAS). However, grain growth is inhibited with increasing Ta concentration by presence of Ta in grain boundary (GB) region. This also results in increase in magnetic coercivity (greater than150 %) as observed from magneto-optical Kerr effect (MOKE). The structural properties were further correlated with magnetic properties as observed from Polarized neutron reflectivity (PNR) and Ferromagnetic resonance (FMR). Effective magnetic moment of the samples, as observed from PNR decreases with increasing Ta concentration and increases with increasing annealing temperature, which is in agreement with FMR results. Scattering length density profiles, observed from simultaneous fitting of XRR and PNR show presence of an oxide layer at surface, as also confirmed from SXAS measurements.

Correlation among hydrogenation, magnetoelastic coupling, magnetic anisotropy, and magnetoresistance in magnetostrictive, hydrogen-absorbing palladium-cobalt alloy films for hydrogen sensing

Hydrogen-absorbing magnetic alloy films, such as palladium-cobalt (PdCo) alloy films, are expected to play a significant role in the next generation of hydrogen sensors. However, effects of hydrogenation on such films are very complex, since these alloys show strong spin-orbit interaction, i.e., strong magnetoelastic coupling. Accordingly, we conducted integrated research on the hydrogenation, magnetoelastic coupling, magnetism, and galvanomagnetic effect of PdCo alloy films having different magnetic anisotropies of longitudinal and perpendicular magnetic anisotropies. As a result, it was revealed that the stress in the film determines its magnetic anisotropy. The magnetoresistance curves of films, consisting of ordinal and anisotropic magnetoresistance effects, correspond well to the magnetization-magnetic field curves. Hydrogenation results in the compressive stress and decreased magnetostriction, which both have a negative influence on the perpendicular magnetic anisotropy energy of the films. Moreover, the influence is observed also in ordinal and anisotropic magnetoresistances. In addition, the increases in coercivity and electronic resistivity due to the incorporated hydrogen atoms (and related defects) are detected. The results are summarized in a correlation diagram, which shows that hydrogen-absorbing magnetic alloy films are very suitable for use in hydrogen sensors—the films can detect hydrogen via various methods such as magnetic anisotropy, galvanomagnetic effect, coercivity, and resistivity.

Influence of nano-VC on the structural and magnetic properties of MnAlC-alloy

Alloys of Mn55Al45C2 with additions of VC nano-particles have been synthesized and their properties evaluated. The Mn55Al45C2(VC)x (x = 0.25, 0.5 and 1) alloys have been prepared by induction melting resulting in a high content of the ferromagnetic τ-phase (> 94 wt.%). Powder X-ray diffraction indicates that nano-VC can be dissolved in the alloy matrix up to 1 at.%. On the other side, metallography investigations by scanning electron microscopy and scanning transmission electron microscope show inclusions of the nanosized additives in the microstructure. The effect of nano-VC on the grain and twin boundaries has been studied by electron backscattering diffraction. The magnetization has been measured by magnetometry up to 9 T while the domain structure has been studied using both magnetic force microscopy as well as Kerr-microscopy. For nano-VC contents above 0.25 at.%, a clear increase of the coercive force is observed, from 57 to 71 kA/m. The optimum appears to be for 0.5 at.% nano-VC which shows a 25% increase in coercive force without losing any saturation magnetization. This independent increase in coercivity is believed to originate from the nano-VC reducing the overall magnetic domain size. Overall, we observe that addition of nano-VC could be an interesting route to increase the coercive force of MnAl, without sacrificing saturation magnetization.

Grain boundary modification and properties enhancement of sintered Nd-Fe-B magnets by ZnO solid diffusion

A grain boundary diffusion (GBD) process using rare earth-free compound as the diffusion source is employed to enhance coercivity of sintered Nd-Fe-B magnets. Typically, a ZnO layer was coated on the Dy-free sintered Nd-Fe-B magnets by sputtering deposition. After a solid diffusion heat treatment, the coercivity and corrosion resistance have been significantly improved. For a 4 mm-thick magnet, the diffusion of ZnO led to a maximum increase of intrinsic coercivity from 1085 to 1290 kA/m. This coercivity enhancement is much higher than those obtained in the previous investigations by GBD of non-RE compounds or alloys. Based on the microstructure analysis, the coercivity improvement is induced by the modifications of the composition and structure of grain boundary phase, which is slightly different from the conventional rare earth-based GBD. The formation of oxides at the triple junction of grains is the main reason for the enhanced corrosion resistance of diffused magnets. The present work thus demonstrated that ZnO can be employed as the GBD source for both coercivity enhancement and corrosion resistance improvement, which are important for preparing low-cost and high-performance Nd-Fe-B permanent magnets.