Surface Modification and Refinement of Nd–Fe–B Magnetic Powder Using ITDT and Phosphoric Acid

Chen, Haibo; Zheng, Jingwu; Cheng, Xinquan; Cai, Wei; Qiao, Liang; Che, Shenglei

doi:10.1007/s11837-021-04850-4

Cited by 3 publications

(4 citation statements)

References 36 publications

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“…The explanation is different from that provided by Shimba et al [ 9 ], probably because Shimba et al treated the NdFeB in phosphoric acid at elevated temperatures, and appropriate results (change in coercively below 2%) were observed only after treating the powder at temperatures above 300 °C. Unfortunately, Chen et al [ 5 ] did not explicitly report the bath temperature, but it is reasonable to assume they performed the treatment with the acid at room temperature. The protective film’s thickness and composition depend significantly on the bath temperature, as shown by Shimba et al [ 9 ].…”

Section: Scientific Literaturementioning

confidence: 99%

“…The method disclosed by Shimba et al [9] is illustrated in Figure 1. Chen et al [5] also used phosphoric acid but mixed it with isopropyl tris-(dioctyl pyrophosphate acyloxy) titanate (ITDT). Coarse NdFeB powder was mixed with zirconia balls in a ball-milling tank, and the chemicals were added.…”

Section: Modification Of the Magnetic Powdermentioning

confidence: 99%

“…At the value of −1808 kJ/mole, the standard enthalpy of formation for neodymium oxide is even larger than for alumina. The enthalpy is large enough that the fine-powdered NdFeB materials glow red-hot during oxidation in the air [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

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Recent Advances in Corrosion Inhibition of Bonded NdFeB Magnets

Primc,

Mozetič

2024

Materials

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Bonded permanent NdFeB magnets are useful in numerous applications, including electric vehicles, and the demand is steadily increasing. A major drawback is corrosion due to inadequate wetting of the magnetic particles by liquid polymers such as polyphenylene sulfide or polyamide. Recently reported methods for corrosion inhibition are summarized, and their applicability is critically evaluated. The phosphorylation of magnetic particles inhibits corrosion but does not enable appropriate properties in harsh environments. The same applies to metallic coatings, which usually contain aluminum and zinc. Advanced epoxy adhesives are a promising solution, although some authors have reported inadequate corrosion resistance. The application of composite coatings seems like an appropriate solution, but the exact mechanisms are yet to be studied.

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Section: Scientific Literaturementioning

confidence: 99%

Section: Modification Of the Magnetic Powdermentioning

confidence: 99%

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Recent Advances in Corrosion Inhibition of Bonded NdFeB Magnets

Primc,

Mozetič

2024

Materials

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“…Strategies employing adhesion promoters, such as silanes [23][24][25] and organo-titanates [26], have been utilized to improve adhesion. Additionally, plasma technology, known for its ability to modify or enhance surface properties, such as corrosion resistance and electrical, thermal, or mechanical characteristics, is gaining popularity.…”

Section: Introductionmentioning

confidence: 99%

The Impact of Plasma Surface Treatments on the Mechanical Properties and Magnetic Performance of FDM-Printed NdFeB/PA12 Magnets

Damnjanović,

Primc,

Zaplotnik

et al. 2024

Materials

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This study presents a novel approach for improving the interfacial adhesion between Nd–Fe–B spherical magnetic powders and polyamide 12 (PA12) in polymer-bonded magnets using plasma treatments. By applying radio frequency plasma to the magnetic powder and low-pressure microwave plasma to PA12, we achieved a notable enhancement in the mechanical and environmental stability of fused deposition modeling (FDM)-printed Nd-Fe-B/PA12 magnets. The densities of the FDM-printed materials ranged from 92% to 94% of their theoretical values, with magnetic remanence (Br) ranging from 85% to 89% of the theoretical values across all batches. The dual plasma-treated batch demonstrated an optimal mechanical profile with an elastic modulus of 578 MPa and the highest ductility at 21%, along with a tensile strength range of 6 to 7 MPa across all batches. Flexural testing indicated that this batch also achieved the highest flexural strength of 15 MPa with a strain of 5%. Environmental stability assessments confirmed that applied plasma treatments did not compromise resistance to corrosion, evidenced by negligible flux loss in both hygrothermal and bulk corrosion tests. These results highlight plasma treatment’s potential to enhance mechanical strength, magnetic performance, and environmental stability.

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