铌对纳米晶Nd2Fe14B合金组织结构与磁性能的影响

采用熔体快淬及晶化退火工艺制备了单相Nd2Fe14B纳米晶合金。研究了添加Nb对Nd12.3Fe81.7-xNbxB6.0(x=0.5,1.0,1.5,2.0,2.5,3.0)系列合金的微观组织、磁性能和晶化行为的影响规律。结果表明:添加Nb可提高晶化温度并稳定非晶相;在退火晶化过程中,加入Nb后形成的析出相可以抑制晶粒长大,使晶粒细化且分布均匀,进而提高了材料的综合磁性能。通过对系列合金磁性能分析可知:Nd12.3Fe81.2Nb0.5B6.0合金在600℃退火处理10min后的磁性能最佳,磁能积(BH)m=141.13kJ.m-3,矫顽力Hci=867.95kA.m-1,剩磁Jr=1.02T。     

Crystal-field levels of Nd3+ in a new langasite compound Nd3CrGe3Be2O14

We report on the crystal-field (CF) levels of Nd³⁺ in Nd₃CrGe₃Be₂O₁₄, a representative of recently synthesized Be-containing langasites. They are the first in the family to contain two magnetic subsystems, 1D chromium and Kagome-like rare-earth ones. High-resolution broad-band temperature-dependent spectra allow us to find all five CF Kramers doublets of the ground ⁴I_9/2 CF multiplet and 38 levels of the excited ⁴I_{11/2, 13/2, 15/2}, ⁴F_3/2, ⁴F_5/2 + ²H_9/2, ⁴F_7/2 + ⁴S_3/2 and ⁴F_9/2 CF multiplets. These data form a basis for a future exploration of this interesting two-sublattice magnet with frustrated interactions. Optical transitions between Kramers doublets of Nd³⁺ indicate magnetic activity of 1D-chromium chains at T < 20 K.     

Study on magnetization reversal behavior for annealed Nd2Fe14B/α-Fe nancomposite alloys

Effect of thermal annealing on the magnetization reversal behavior ofα-Fe/Nd2Fe14B alloys was investigated. A drastic in-crease of the remanence Mr from 0.67 up to 0.87 T and remanence ratio Mr/Ms from...     

Magnetomechanical Properties of the Alloy Nd2Fe14B

We have studied the elastic and inelastic properties of the polycrystalline ferromagnet Nd₂Fe₁₄B in the temperature range 20–550 °C. We used the low-frequency (80 Hz) internal friction method to measure the Curie point of Nd₂Fe₁₄B. We observe an internal friction peak at T ≈ 280 °C. The nature of this peak is explained in terms of the magnetoelastic saturation concept.__________Translated from Poroshkovaya Metallurgiya, Nos. 3–4(442), pp. 87–93, March–April, 2005.     

Nd2Fe14B/α - Fe/Nd2Fe14B磁性三层膜的微磁学模拟

以Nd2 Fe14B/α - Fe/Nd2 Fe14B三层膜为对象,应用微磁学理论计算了该体系的磁滞回线,并对其磁性能与软磁层厚度的关系进行了分析.结果表明,当软磁层厚度小于临界尺寸(5nm)时,磁滞回线为矩形,三层膜完全耦合；当软磁层厚度为5nm时,最大磁能积可达到最大值642.51 kJ/m3.在所研究的软磁层厚度范围内,随着软磁层厚度的增加,三层膜矫顽力单调下降.     

钕铁硼中不同状态氧释放行为的研究(英文)

钕铁硼磁体中氧含量偏高是影响其大工业生产、造成钕铁硼磁体性能偏低的主要原因之一,因此合理地控制氧在钕铁硼中含量及其存在状态,为分析工作提出了重要研究课题。依据样品中不同状态氧与碳的结合能不同的特点,本文使用惰气熔融红外吸收法对钕铁硼材料样品中不同状态氧进行了定性和定量的方法研究。首先通过斜率加热模式,确定钕铁硼样品在不同分析加热电流下存在着两种状态氧化物。根据斜率加热模式下得到的每种状态氧化物对应的释放条件,使用分段加热模式,完全分离两种状态氧的释放峰。对原始样品和第一段加热后的中间产物分别进行x射线衍射     

利用粉末掺和技术生产(Nd,Mm)2(Fe,Co,Ni)14B型烧结磁体

概述了利用粉末掺和技术制得（Nd，Mm）2（Fe，Co，Ni）14B型各项异性磁体的基本情况及该材料的主要性能。     

Nd2Fe14B/Fe3B基纳米复合粘结磁体的磁特性

通过实验研究了Nd2Fe14B／Fe3B双相纳米复合磁粉分别与几种不同性能的磁粉复合成粘结磁体后磁性能的变化。通过对复合磁体的理论分析得知，由Nd2Fe14B／Fe3B与RE2Fe14B或铁氧体磁粉复合成的粘结磁体中，成分间并未发生化学反应。以Nd2Fe14B／Fe3B铁氧体复合粘结磁体为例，根据理论分析推出的剩磁Br-成分含量关系曲线与实际曲线吻合得很好，表明剩磁与成分含量间存在着近似的线性关系，从而可通过数学手段建立磁性能参数与成分含量的函数关系式，用于简化混粉工艺。另外，添加铁氧体可对该复合磁体较差的热稳定性起到补偿作用，并减少了磁不可逆损失。     

Grain-Size Composition and Coercive Force of Nd2Fe14B Alloy Powder in a Finely Divided State

The change in grain-size composition and magnetic properties of powder prepared by grinding cast alloy Nd₂Fe₁₄B in a ball mill for different times is studied. It is shown that during grinding the coercive force of the powder increases uniformly at first reaching a maximum, and then it decreases. It is established that this phenomenon is not due to powder oxidation during grinding but a reduction in the level of particle uniaxial anisotropy caused by deformation of their surface layer during grinding. The change in coercive force of Nd ₂Fe₁₄B alloy powder on grinding obeys the same features that are observed with mechanical grinding of other uniaxial magnetic materials.