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High-performance anisotropic SmCo-based magnet with novel microstructure

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Journal of Rare Earths 2024年第8期42卷 1539-1545,I0005页

作者： Yingchang Li Zicao Xing Nengjun Yu Zesong Ren Minxiang Pan Qiong Wu Hongliang Ge minggang zhu Wei Li College of Materials and Chemistry China jiliang UniversityHangzhou 310018China Division of Functional Materials Research Central Iron and Steel Research InstituteBeijing 100081China

A novel micro structure of magnetically anisotropic Sm Co-based magnet with high-performance is *** magnet consists of SmCo_(7)-H(TbCu_(7)-hexagonal type),Sm_(2)Co_(17)-H(Th_(2)Ni_(17)-hexagonal type)and SmCo_(3)-R(SmCo_(3)-rhombohedral type)*** maximum magnetic energy product of the magnet is 231.69 kj/m^(3),and the intrinsic coercivity is 1005.47 kA/*** outstanding intrinsic coercivity temperature coefficient(β)of-0.125%/K between 298 and 773 K is obtained,which is very close to theβof commercial high-temperature Sm_(2)Co_(17)-based sintered *** initial magnetization curve indicates that the coercivity mechanism is controlled by a domain wall pinning *** SmCo_(3)-R lamellar phase may be a potential pinning center or self-pinning *** microstructure of the magnet is different from that of any previous SmCo-based *** findings provide a new idea for preparing high-performance SmCo-based permanent magnets.

关键词： Rare earths Permanent magnet Composite magnet Melt-spinning Microstructure

(Nd,Ce,La)-Fe-B快淬带研究进展

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稀有金属 2024年第1期48卷 105-117页

作者：贺有年郭朝晖靖征朱明刚钢铁研究总院功能材料研究所北京100081

Nd-Fe-B永磁体需求的持续增长极大地加速了Nd,Pr,Dy和Tb等关键稀土元素的消耗,不仅导致这些低丰度稀土元素的价格上涨,而且还造成高丰度稀土Ce和La的大量积压。为了均衡高效利用稀土资源Ce和La,近年来,世界各国围绕(Nd,Ce,La)-Fe-B基永... 详细信息

Nd-Fe-B永磁体需求的持续增长极大地加速了Nd,Pr,Dy和Tb等关键稀土元素的消耗,不仅导致这些低丰度稀土元素的价格上涨,而且还造成高丰度稀土Ce和La的大量积压。为了均衡高效利用稀土资源Ce和La,近年来,世界各国围绕(Nd,Ce,La)-Fe-B基永磁材料开展了大量研发工作,发现添加Ce,La或La-Ce的永磁体不仅可降低成本,而且在Ce含量20%~30%(原子分数)时或La及La-Ce含量约10%时,可能呈现出矫顽力反常增大,而在Ce和/或La含量低于50%时,磁体仍会具有令人满意的磁性能,显示出极为广阔的应用前景。目前,研究和开发高性价比的Ce,La或La-Ce掺杂(Nd,Ce,La)-Fe-B永磁材料已成为磁性材料热点之一。对Ce-Fe-B磁体的结构和本征磁性进行了介绍,然后对Ce-Fe-B快淬薄带的磁性、微观结构和相析出行为,(Nd,Ce)-Fe-B快淬带的矫顽力反常增大、元素偏析和相分离,以及La和La-Ce添加对(Nd,Ce,La)-Fe-B快淬带微观结构和磁性能等方面的最新研究进展进行了综述,最后对相关领域未来研究发展趋势进行了展望。

关键词： Ce-Fe-B (Nd,Ce,La)-Fe-B 熔体快淬带磁性能微结构

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热压/热变形钕铁硼永磁材料研究进展

中国稀土学报 2024年第1期42卷 1-12,I0001页

作者：左思源李雅婧郑立允黄光伟朱明刚李卫河北工程大学材料科学与工程学院河北省稀土永磁材料与应用工程研究中心河北邯郸056038 河北工程大学机械与装备工程学院河北邯郸056038 钢铁研究总院有限公司北京100081

对热压/热变形钕铁硼磁体的制备技术进行综述,对热压/热变形钕铁硼块体和反挤压钕铁硼磁环不均匀性的成因和特点、高性能热压/热变形钕铁硼磁体的制备技术、热压钕铁硼磁环的特点和分类以及反挤压钕铁硼磁环制备过程中裂纹产生的原因、... 详细信息

对热压/热变形钕铁硼磁体的制备技术进行综述,对热压/热变形钕铁硼块体和反挤压钕铁硼磁环不均匀性的成因和特点、高性能热压/热变形钕铁硼磁体的制备技术、热压钕铁硼磁环的特点和分类以及反挤压钕铁硼磁环制备过程中裂纹产生的原因、解决方案以及粘模润滑等问题进行了阐述,并对钕铁硼磁环制备关键技术的前景进行了展望。

关键词：热压/热变形工艺钕铁硼块体钕铁硼磁环磁性能

一种用于误差通道预辨识的气动冲击锤特性分析

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振动与冲击 2024年第5期43卷 166-172页

作者：李锋杨铁军吴磊徐阳黎文科李新辉朱明刚哈尔滨工程大学动力与能源工程学院哈尔滨150001 哈尔滨工程大学青岛创新发展基地山东青岛266000

针对船舶机械设备主动减振系统的误差通道预辨识问题,研制了一种气动冲击锤作为激励力源。为了解气锤的特性,对其开展仿真和试验研究。首先通过建立气锤气体做功过程的热-机耦合模型和锤头冲击过程的动力学模型,得到锤头冲击速度、冲击... 详细信息

针对船舶机械设备主动减振系统的误差通道预辨识问题,研制了一种气动冲击锤作为激励力源。为了解气锤的特性,对其开展仿真和试验研究。首先通过建立气锤气体做功过程的热-机耦合模型和锤头冲击过程的动力学模型,得到锤头冲击速度、冲击力及冲击时间之间的数学物理关系,对比分析活塞组件工作过程的仿真和试验测试结果;然后探讨复位弹簧刚度、活塞与气缸壁之间的黏性阻尼、气缸内的死区容积等结构动力学参数对锤头冲击速度的影响。最后对气锤冲击力的仿真和测试结果进行对比分析,并应用气锤对弹性结构进行传递函数测试,与传统力锤激励的测试结果进行比较,验证气锤对结构动力学特性参数测试的可行性和有效性。

关键词：主动减振误差通道预辨识气动冲击锤仿真和试验研究

Statistical model of magnetization reversal in Nd-Fe-B sintered magnets

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Rare Metals 2006年第Z1期25卷 521-525页

作者： WANG Huijie zhu minggang LI Wei ZHANG Xin Division of Functional Materials Central Iron & Steel Research Institute Beijing 100081 China Division of Functional Materials Central Iron & Steel Research Institute Beijing 100081 China Division of Functional Materials Central Iron & Steel Research Institute Beijing 100081 China China Petroleum Materials Tianjin Corporation Tianjin 300204 China

Statistical model of magnetization reversal was used to simulate the magnetization reversal behavior in the sintered Nd-Fe-B magnets with double grain-size distributions due to the abnormal grain growth (AGG). The magnetic properties and mechanical properties due to the formation of AGG grains in Nd-Fe-B sintered magnets were tested. The results show that the magnetic properties, especially the rectangularity were severely deteriorated after the formation of the AGG grains and a step was shown on the demagnetization curve, and the occurrence of AGG may account for the poor rectangularity and existence of the step on demagnetization curve according to the statistical model of magnetization reversal. The fracture toughness and bending strength are lowered because of the stress concentration in the AGG grains. The SEM images show that the formation of AGG grains is caused by the solid sintering due to the absence of RE-rich phase. Statistical model of magnetization reversal can qualitative by explain the dependence of the magnetization reversal behavior on the grain size in the Nd-Fe-B sintered magnets.

关键词： sintered Nd-Fe-B magnets mechanical properties magnetization reversal abnormal grain growth

Magnetic microstructure and coercivity mechanism of high performance Nd-Fe-B magnets

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Rare Metals 2006年第Z1期25卷 630-632页

作者： zhu minggang LIU Xingmin FANG Yikun LI Zhengbang LI Wei Central Iron & Steel Research Institute Beijing 100081 China Central Iron & Steel Research Institute Beijing 100081 China Central Iron & Steel Research Institute Beijing 100081 China Central Iron & Steel Research Institute Beijing 100081 China Central Iron & Steel Research Institute Beijing 100081 China

Magnetic microstructure of high performance Nd-Fe-B magnets was investigated by using magnetic force microscopy. The correlation between magnetic microstructure and coercivity for high performance Nd-Fe-B magnets was studied. It is found that the magnets with different coercivity mechanism take on different microstructures and magnetism. Moreover, the magnetic microstructures of high performance permanent magnets can be explained by the starting field theory model.

关键词： Nd-Fe-B permanent magnets magnetic domains reversal of magnetism starting field theory

Effect of magnetic layer thickness on magnetic properties of Ce-Fe-B thin films

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Journal of Rare Earths 2018年第6期36卷 619-622页

作者： Yachao Sun minggang zhu Wei Liu Rui Han Wei Li Division of Functional Material Central Iron & Steel Research Institute Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

The Ce;Fe;B thin films with a notable out-of-plane c-axis texture were prepared by DC magnetron sputtering on a Ta buffer layer. The morphological and magnetic properties were investigated. The thickness of the magnetic layer had a dramatic effect on the formation of Ce;Fe;B phase,and excellent magnetic properties(H;≈4.25 kOe, M;/M;≈0.81) were observed for the Ce-Fe-B film with the thickness d;= 200 nm. The results of the hysteresis loops for Ce-Fe-B film（d;= 200 nm） at various measured temperatures show that a decoupling between the hard and the soft phases is observed at low temperatures, which is due to the regions with quite low anisotropy provided by the a-Fe. Moreover. it is clear that significantly various magnetization behaviors between the films with d;= 200 and 300 nm were observed with a similar trend due to the existence of the a-Fe soft phase.

关键词： Permanent magnets Ce-Fe-B film Hysteresis loops Reversible susceptibility Rare earths

Temperature stability and microstructure of ultra-high intrinsic coercivity Nd-Fe-B magnets

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Rare Metals 2008年第4期27卷 358-361页

作者： HU Zhihua CHENG Xinghua zhu minggang LI Wei LIAN Fazeng Key Laboratory of the Ministry of Education of China for Anisotropy and Texture of Materials Northeastern University Shenyang 110004 China Division of Functional Materials Central Iron ＆ Steel Research Institute Beijing 100081 China Advanced Technology and Materials Co. Ltd. Beijing 100081 China

The variations of intrinsic coercivity and remanence of sintered Nd-Fe-B magnets with ultra-high intrinsic coercivity were investigated. The results showed that the intrinsic coercivity and remanence declined simultaneously with increasing temperature, but the squareness of the magnets has hardly been changed. The temperature coefficients of remanence （α） and coercivity （β） for the magnets were calculated by two different methods, and the variations of the temperature coefficients and the microstructure of sintered Nd-Fe-B magnets were analyzed. The temperature coefficients of remanence （α） and coercivity （β） for the sintered magnets are very small, and the existence of fine microstructure is necessary to obtain sintered Nd-Fe-B magnets with ultra-high intrinsic coercivity.

关键词： Nd-Fe-B magnets intrinsic coercivity sintering remanence temperature coefficient

The microstructure and magnetization reversal behavior of melt-spun (Nd_(1-x)Ce_x)-Fe-B ribbons

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Journal of Rare Earths 2018年第1期36卷 95-98页

作者： liwei song nengjun yu minggang zhu qiang wang wei li division of functional materials central iron and steel research instituteBeijing 100081China key laboratory of national education ministry for electromagnetic processing of materials northeastern universityShenyang 110819China school of materials science and engineering northeastern universityShenyang 110819China

In this study, the alloy ingots with nominal compositions of （Nd1_xCex）31FebalCoo.2Gao.1B （x = 0, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%） were prepared and then melt-spun to form nanocrystalline ribbons at the wheel speed of 20 m/s. XRD results show that all melt-spun ribbons exhibit the tetragonal structure （Nd,Ce）2Fe14B phase with the space group P42]rnmm. The Curie temperature and lattice constant decrease with the increase of Ce content. The Curie temperature decreases gradually from 306 to 247 ~C with the increase of Ce content. Those results indicate that Ce element has been incorporated into Nd2Fe14B main crystalline phase and formed （Ce,Nd）-Fe-B hard magnetic phase. It is also found that the remanence ratio （Mr/Ms） decreases from 0.693 to 0.663 and the coercivity （Hc） decreases from 18.7 to 14.2 kOe with the increase of Ce content. However, a relatively high coercivity of 18.3 kOe for （Ndl xCex）*** （x = 0.2） melt-spun ribbon is achieved. The coercivity is sensitive to microstructure. The AFM patterns show the sample （x - 0.2） has the most uniform and finest micro- structure. The magnetization reversal behavior （0M plots） is discussed in detail. The positive 0M value is observed in every sample, which confirms the existence of exchange coupling interaction. Evidently, the OM maximum value reaches 0.9 in the sample （x - 0.2）. It is indicated that the intergranular exchange coupling effect is the strongest, which is consistent with coercivity enhancing.

关键词： Ce contentMelt-spun ribbonsHigh coercivityMicrostructureRare earthsMagnetization reversal