Journal of Materials Research and Technology-JMR&T
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2022
·
IF 6.267
Jingwu Zheng,Siyuan Wang,Shuan Zhang,Wei Cai,Liang Qiao,Haibo Chen,Yao Ying,Wangchang Li,Jing Yu,Shenglei Che
In this paper, a corrosion-resistant glutamic acid (Glu)-Cu-Nano-Al 2 O 3 composite coating with both hydrophobicity and self-healing characteristics was electrodeposited on the sintered Nd-Fe-B surface. The influence of the amount of Nano-Al 2 O 3 added in the acidic Cu 2+ -glutamate (Glu 2− ) solution on the performance of the composite coating was studied, the results show that Nano-Al 2 O 3 inclusion can make the surface of the composite coating appear papillary particles and make the composite coating hydrophobic. By analyzing the products of the composite coating after corrosion in 3.5% NaCl solution, it is shown that the codeposition copper dihydroglutamate (CuGlu 2 H 2 ) and Glu particles in the composite coating are released and dissolved in the solution with pH = 6.5 after copper corrosion, and then complexed with Cu 2+ produced by corrosion to form an insoluble copper glutamate (CuGlu) passive film, which was deposited on the corroded coating to achieve self-repairing function and prevent further corrosion. The hydrophobicity and self-repairing function of the composite coating ensure that the sintered Nd-Fe-B has excellent corrosion resistance.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 68
·38850-38859
·
IF 2.936
Yaozu Guo,Dong Zhao,Junhua You,Wenli Pei,Yingdong Qu,Xiaoyang Wang,Qingyu Meng
Nd2Fe14B nanoparticles were successfully prepared by using a low-energy chemical method. The microscopic characteristics and formation mechanisms of the phases were investigated at each stage during the preparation of Nd-Fe-B nanoparticles. The Nd-Fe-B intermediates, Nd-Fe-B oxides and reduced Nd-Fe-B nanoparticles were detected and analyzed by using TEM, STEM, XRD, SEM, VSM and Rietveld calculations. The results showed that the intermediate of Nd-Fe-B consisted of Fe3O4 and Nd and Fe elements surrounded by nitrile organic compounds. The Nd-Fe-B oxide was composed of NdFeO3 (48.619 wt%), NdBO3 (31.480 wt%) and α-Fe (19.901 wt%), which was formed by the reaction among Nd, Fe3O4 and B2O3. NdFeO3 and NdBO3 exhibited a perovskite-like lamellar structure, and the grain size was smaller than that of α-Fe. Nd-Fe-B particles were mainly composed of Nd2Fe14B and α-Fe phases. The small particles of NdFeO3 and NdBO3 and the interstitial position between oxide particles and α-Fe were more favorable for the formation of Nd2Fe14B particles. At the same time, the surface of α-Fe particles can also diffuse to form Nd2Fe14B nanoparticles. The coercivity of Nd-Fe-B particles was 5.79 kOe and the saturation magnetization was 63.135 emu g−1.
研究领域:
材料科学
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纳米材料
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磁性材料
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无机非金属材料
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固体化学
✓ 已验证
DOI
高影响因子
Surfaces and Interfaces
·
2025
·
IF 6.3
Wei Cai,Xinqi Zhang,Jianwei Zheng,Jingwu Zheng,Rongyao Li,Haibo Chen,Liang Qiao,Yao Ying,Wangchang Li,Jing Yu,Juan Li,Shenglei Che
To address the operational safety hazards associated with using high-concentration inorganic phosphoric acid as a surface treatments to enhance the high-temperature oxidation resistance of Nd-Fe-B magnetic powders, this study innovatively proposes an environmentally friendly organic phosphonic acid (methylene diphosphonic acid, MDPA) as an alternative solution. By comparing the effects of inorganic phosphoric acid and MDPA surface treatments on the magnetic properties and thermal stability of magnetic powders, it was found that phosphating-treated samples exhibited slight decrease in coercivity H cj and maximum magnetic energy product (BH) max at room temperature compared to untreated samples. However, at 340 °C, the (BH)max and Hcj of untreated samples dropped sharply by 98.55 % (from 4.97 to 0.07 MGOe) and 92.72 % (from 9.62 to 0.70 kOe), respectively. In contrast, the inorganic phosphate-treated samples showed only a slight decline of 13.55 % (from 4.53 to 3.92 MGOe) and 1.22 % (from 9.39 to 9.28 kOe). The MDPA-treated samples exhibited the best thermal stability, with minimal losses in both (BH)max and Hcj, decreasing by only 6.88 % (from 4.66 to 4.34 MGOe) and 0.69 % (from 9.43 to 9.36 kOe), respectively. Microstructural analysis revealed that the dense metal phosphate conversion layer formed during phosphating was the key to maintaining high-temperature magnetic performance. Specifically, inorganic phosphoric acid treatment preferentially corroded Nd-rich intergranular phases, resulting in a higher Nd content in the conversion layer. In contrast, the iron phosphate salt formed by MDPA treatment dominates the transformation layer, effectively reduces the damage to the microstructure of the magnetic powder. Our research provides a surface treatment solution that combines safety and efficiency for the performance protection of rare-earth magnetic powders in high-temperature injection molding processes.
研究领域:
材料科学
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表面工程
·
磁学
·
环境化学
·
稀土材料
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Haiyan Chen,Haibo Xu,Yeyin Li,Zhibin Li,Xin Wang,Bo Jiang,Rongshun Lai,Wenbin Fan,Chuntao Xiang,Zhi Yang,Xiao Chi,Qiang Ma
Selective chlorination has been proven to be an energy-efficient and environmentally friendly method for recycling rare earth elements (REEs) from Nd-Fe-B waste. However, little attention has been paid to the in-depth study of Nd-Fe-B sludge chlorination until now. In this work, four isoconversion methods combined with an unreacted shrinkage core model were employed for the first time to investigate the kinetic behavior of the chlorination reaction between FeCl 3 and Nd-Fe-B sludge. Through thermodynamic calculations, TG-DSC, SEM-EDS, and XRD analysis, the chlorination process and phase transformation behavior of Nd-Fe-B sludge were elucidated. The results show that under optimal conditions (350 °C, FeCl 3 /RE=3:1, 2 h), the RE components in Nd-Fe-B sludge are selectively chlorinated to RECl 3 , avoiding the formation of REOCl, while the iron components primarily exist in the leaching residue as Fe 2 O 3 or FeOCl. And 97.32 % of REEs are selectively extracted into the leachate, while the iron leaching rate is only 4.02 %. Besides, the STA method is the most accurate, yielding E α-STA and A values of 75.01 kJ/mol and 2.6 × 10 6 min −1 , respectively. The reaction control mechanism was analyzed in three steps. In Step 1 (0.05 < α < 0.63) and Step 2 (0.63 < α < 0.75), the diffusion reaction mechanism controls the overall reaction, In Step 3 (0.75 < α < 0.95), the nucleation reaction takes over the control, which provides a good explanation for the change in E α-STA . However, the control step of the entire chlorination reaction is dominated by the internal diffusion process.
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产品关联
DOI
高影响因子
Materials Research Express
·
2019
·Vol. 6
·期 10
·106108
·
IF 1.449
Wenli Pei,Xiaohan Zhang,Qinyu Meng,Jifeng Zhou,Yaozu Guo,Junhua You,Dong Zhao,Xiaoyang Wang
Nd-Fe-B nanoparticles have been successfully prepared by using an optimized low-energy chemical method. The effects of reduction-diffusion time on the microstructure and properties of Nd-Fe-B nanoparticles were investigated by using TEM, XRD, SEM, VSM and Rietveld calculations. The results showed that when the reduction-diffusion time was short, the reaction was not sufficient, which resulted in a residual H5Nd2 phase. When the reduction-diffusion time was prolonged, the H5Nd2 phase gradually decreased and the relative crystallinity of Nd2Fe14B phase gradually increased. Moreover, the grain size grew and the rich Nd phase appeared gradually around the grains. Furthermore, as the reduction-diffusion time was prolonged, the coercive force of Nd-Fe-B nanoparticles increased first and then decreased. When the holding time was extended to 180 min, the coercive force reached a maximum of about 4.85 kOe and the magnetic energy product was about 2.5 MGOe.
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Hongxing Chen,Renquan Wang,Jun Li,Chang Liu,Xiaojiao Yang,Ying Liu
The combination of high coercivity and resistivity is a strong requirement for permanent magnets to resist thermal demagnetization under complex operating conditions. However, this still remains a challenge for conventional strategies, which always sacrifice the maximum energy product as the coercivity or resistivity increases. In this work, we report a unique strategy of introducing only 0.1 wt% of insulating nano-diamonds (NDs) into the hot-deformed Nd-Fe-B magnets to significantly and simultaneously improve both magnetic properties ( H ci , B r , (BH) max and H k / H cj ) and resistivity. In particular, the coercivity increased by 60% from 746 to 1193 kA/m. Further microstructure observations indicate that this exceptional effect stems from NDs can effectively inhibit the formation of coarse grains and optimize the distribution of Nd-rich phases, ensuring a strong pinning effect to enhance hard magnetic performance. Meanwhile, the presence of additional grain boundaries and NDs can also lead to higher resistivity by preventing the movement of free electrons. Our work provides a distinctive strategy for interface modification with excellent comprehensive performance in permanent magnets.
研究领域:
材料科学
·
磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Yaozu Guo,Junhua You,Wenli Pei,Yingdong Qu,Dong Zhao,Zhengwen Yang
This paper reports a novel chemical method to synthesize Nd-Fe-B magnetic nanoparticles . The fabrication mechanism of the particles have been studied through understanding formation of the corresponding intermediate phases as well as their microstructures after annealing and reduction-diffusion processes as function of the (C 2 H 5 ) 3 NBH 3 content. Nd-Fe-B intermediate phases were composed of small Fe 3 O 4 particles and Nd and Fe microcrystals encapsulated with nitriles . Fe 3 O 4 was reduced by BH 3 − into α-Fe as the (C 2 H 5 ) 3 NBH 3 content increased. After annealing, Nd-Fe-B oxide particles gradually agglomerated as the (C 2 H 5 ) 3 NBH 3 content increased, which affected the particle sizes after the reduction-diffusion step. Mixture of Nd 2 Fe 14 B and H 5 Nd 2 was obtained from precursors synthesized with 1.5 and 2.5 mmol of (C 2 H 5 ) 3 NBH 3 . Magnetic properties of these mixtures demonstrated soft magnetic phase characteristics. Relatively pure Nd 2 Fe 14 B nanoparticles with a coercivity of 5.09 kOe and magnetic energy product (BH max ) of 2.862 MGOe were obtained when (C 2 H 5 ) 3 NBH 3 initial content was 3.5 mmol. Exchange coupling nanoparticles of Nd 2 Fe 14 B, Fe 3 B and Fe 2 B were obtained with the coercivity of 3.787 kOe and (BH) max equal to 4.871 MGOe at (C 2 H 5 ) 3 NBH 3 content of 4.5 mmol.
✓ 已验证
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2026
·
IF 7.9
Han Yu,Ying Wang,Zhen Shi,Chenxi Fang,Hang Zeng,Junting Sun,Vilko Mandić,Xuefeng Zhang
Although superhydrophobic coatings have been widely employed for corrosion protection due to their low surface energy, their low surface energy characteristic also results in weak interfacial adhesion and the influence of interfacial adhesion on the overall anti-corrosion performance remains poorly understood. Herein, we explored the corrosion resistance of superhydrophobic coatings on sintered Nd-Fe-B magnets from the perspective of work of adhesion (Wₐ), which represented the interfacial stability and bonding strength. By precisely controlling the PDA shell thickness and the degree of hydrophobization, the work of adhesion can be regulated correspondingly. The results revealed that the overall anti-corrosion performance of superhydrophobic coatings was directly proportional to the work of adhesion. At an optimized Wₐ of 49.44 mN·m -1 , the coated magnet exhibited a low corrosion current density of 1.09 × 10 −8 A/cm 2 , which was three orders of magnitude lower than that of 3.27 × 10 −5 A/cm 2 for bare Nd-Fe-B magnet. Moreover, outstanding protection durability was also demonstrated in both acidic and alkaline environments with robust interfacial contact. In contrast, weak adhesion induced the formation of interfacial gaps, which served as preferred penetration pathways for the corrosive medium. This study evidenced the importance of interfacial structural integrity, revealing the critical role of adhesion layer design in enabling robust and durable anti-corrosion performance of superhydrophobic coatings.
✓ 已验证
DOI
高影响因子
Small
·
2025
·
IF 12.1
Zhen Shi,Chenxi Fang,Jiaqian Li,Sateesh Bandaru,Muwen Liu,Lizhong Zhao,Xuefeng Zhang
In spite of superior magnetic properties, neodymium–iron–boron (Nd-Fe-B) applications in harsh environments have been greatly hindered by their susceptibility to corrosion, humidity, mechanical, and temperature attacks. Herein, a construction strategy of robust slippery liquid-infused porous surfaces (SLIPS) coatings is proposed via the multi-dimensional design of surface, bulk coating, and interface. The manipulation of colloidal states of silica particles by chemical hydrophobization allows for building a dense polymer network, enhancing interfacial adhesion and locking lubricant film effectively. The resulting coating is demonstrated to be extremely stable, endowing the magnet with excellent liquid repellency, anti-corrosion, and anti-icing properties. Strikingly, no trace of corrosion is detected after 136-day immersion in 3.5 wt.% NaCl solution and the impedance modulus at 0.1 Hz can be maintained as the initial of 3.31 × 10 8 Ω·cm 2 even after 132-day immersion, which is far superior to that of commercial Ni-Cu-Ni, Zn, and EP coatings. Additionally, anti-icing performance at low temperatures is evidenced by the delayed icing time and decreased ice adhesion strength. Importantly, the self-healing property offers the surface intensified durability even after mechanical damage. This work demonstrates a construction strategy of robust SLIPS coatings with a multi-dimensional design, enabling the practical applications of Nd-Fe-B magnets in extreme environments like offshore wind turbines.
研究领域:
材料科学
·
表面工程
·
腐蚀防护
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）