Magnetic properties and magnetization mechanism of anisotropic NdFeB/SmFeN hybrid bonded magnets prepared with different coercivity NdFeB powders

Anisotropic NdFeB/SmFeN hybrid bonded magnets were prepared by warm compaction process under an orientation magnetic field of 22 kOe,mixing with anisotropic SmFeN powders in different addition and HDDR-NdFeB powders in different coercivity.With the addition of 20 wt% SmFeN,the density and remanence of hybrid magnets increase from 5.58 g/cm³,8.4 kGs to 6.02 g/cm³,9.0 kGs,respectively.And as the addition amount of SmFeN powders varies from 20 wt% to 40 wt%,the maximum energy ...     

工艺参数对锶铁氧体预烧料磁性能的影响

以铁鳞、碳酸锶为原料, 天青石, 高岭土及碳酸钙等为添加剂来制备铁氧体预烧料,借助振动样品磁强计, X 射线仪等仪器, 研究了不同的配方n 值, 预烧温度, 铁鳞粒度以及添加剂含量对铁氧体预烧料磁性能的影响。     

大西沟菱铁矿石磁化焙烧—弱磁选试验研究

对大西沟菱铁矿石在中性气氛条件下进行磁化焙烧—弱磁选试验研究。结果表明,在焙烧温度为650℃、焙烧时间为40 min条件下直接焙烧,焙烧产品磨细至-0.043 mm占95%,在磁场强度为104 k A/m条件下弱磁选,获得的精矿铁品位为57.09%、铁回收率为90.17%,Si O2含量为12.03%,精矿还需进行提铁降硅试验。焙烧使矿石中的菱铁矿和褐铁矿转变为强磁性的磁铁矿,焙烧后物料的磁化强度和比磁化率均显著提高,增大了物料中铁矿物与脉石矿物的磁性差异,因而可通过弱磁选进行有效分离。     

磁处理对抑制黄铁矿的影响及其机理探讨

利用纯矿物试验研究了抑制剂 CK的磁处理对铜硫两种矿物可浮性的影响 ,采用接触角测试及矿物表面吸附量测试对磁处理强化黄铁矿抑制机理进行了探讨。与常规浮选相比较 ,磁场可强化对黄铁矿的抑制作用 ,促进抑制剂 CK在黄铁矿矿物表面的吸附 ,增加矿物表面的亲水性     

横场和晶场作用下S=2的Ising模型的磁性质

采用平均场理论, 计算了高自旋S =2 且处于外界横向磁场的Ising 模型, 推导出系统有限温度下磁矩及自由能的理论计算公式, 利用数值计算方法得到了系统在有限温度下的磁化曲线, 重点考察了有限温度下纵向晶场D 和横场Ψ对自旋系统磁化曲线及自由能的影响。从磁化曲线中观察到了4 种相变特征:一级有序-有序相变、一级有序-无序相变、二级有序-无序相变及重入现象。研究发现重入现象只发生于存在横向磁场的情况下;一级相变发生在狭小的晶场和横场范围内, 一级有序-有序相变的存在范围更加狭小, 而二级有序-无序相变存在于较大的晶场和横场范围内;总体上说一级相变对应的温度较二级相变对应的温度低;晶场是促进相变发生的因素;横场是限制相变发生的因素。     

不断改进的酒钢选矿厂竖炉焙烧工艺

阐述了采用磁化焙烧工艺处理酒钢矿石是有效合理的,并在生产中不断优化和改进。介绍了鞍山式竖炉在酒钢选矿厂的应用与发展,特别是双层燃烧室竖炉工业试验及应用情况。提出了双层燃烧室竖炉存在的问题及改进方法。     

油管漏磁检测中的磁化技术

在磁性无损检测中,磁化是实现检测的第一步,它决定着被测对象能否产生出可被测量和可被分辨的磁场信号,同时也影响着检测信号的性能特性和检测装置的结构特性.因此,针对被测构件结构特点和测量目的,选择磁化方式和磁化强度是磁化的关键.     

Crystal structure, thermal expansion and magnetic properties of new compound Dy1.2Fe4Si9.8

The new ternary compound Dy_1.2Fe₄Si_9.8 have been prepared and studied by means of X-ray powder diffraction technique and vibrating sample magnetometer. The ternary compound Dy_1.2Fe₄Si_9.8 crystallizes in the hexagonal Er_1.2Fe₄Si_9.8-type structure, space group P6₃/mmc (no. 194) with lattice parameters a = 0.39415(1) nm and c = 1.52771(3) nm. The crystal structural refinement of the compound Dy_1.2Fe₄Si_9.8 has been performed by using Rietveld method. Lattice thermal expansion studies on the compound were carried out in the temperature range from 298 to 1013 K. The variation of the unit cell parameters shows that the unit cell parameters increase with the increase in temperature. The coefficients of average lattice thermal expansion along various axes in the temperature range from 298 to 1013 K are , and . The temperature dependence of the magnetization for the compound was also investigated in the range from 90 to 300 K. The experimentally determined magnetic effective paramagnetic moment is μ_eff = 11.3μ_B per formula unit (10.3μ_B per Dy atom).     

Magnetic Field and Displacement Sensor Based on Giant Magneto-Impedance Effect

A two-core transducer assembly using a Fe_73.5Nb₃Cu₁Si_13.5B₉ ribbon to detect a change of magnetic field is proposed and tested for displacement (linear and angular) and current sensor. Two identical inductors, with the ribbon as core, are part of a two-series resonance network, and are in a high impedance state when excited by a small AC field of 1 MHz in the absence of a DC biasing field (H_dc). When the magnetic state of one inductor is altered by the biasing field, produced by a bar magnet or current carrying coil, an AC signal proportional to H_dc is generated by the transducer. The results for the sensitivity and linearity with displacement (linear and angular) of a magnet and with field from the current carrying coil are presented for two particular configurations of the transducer. High sensitivities of voltage response as much as 12 µV/µm and 3 mV/degree have been obtained for the transducer as a linear and angular displacement sensor, respectively, in the transverse configuration of exciting AC and biasing DC fields.