Fe-Si-B非晶磁粉芯的制备及其软磁性能

采用气流磨破碎的Fe78Si9B13非晶合金粉末制备了非晶磁粉芯,研究了绝缘包覆工艺和热处理工艺对磁粉芯性能的影响。结果表明经磷酸丙酮溶液钝化处理的粉末制备的磁粉芯其性能要优于其他经氧化物粉末、矿物粉、硅酸盐包覆处理的粉末制备的磁粉芯。随着热处理温度的升高,磁粉芯的相对磁导率呈先增大后减小趋势,当热处理温度为400℃时,其所制备的磁粉芯的相对磁导率μe最大(26),损耗Ps最低(11.1 W/kg,50 kHz),相应的矫顽力Hc和品质因数Q分别达到最低值12.1 A/m和最高值273.9。     

铁铜铌硅硼非晶磁粉芯性能研究

采用聚乙烯醇做粘结剂,制备了Fe73.5Cu1Nb3Si13.5B9非晶磁粉芯。并用XRD、SEM等手段对其进行了表征。还对其磁性能进行了研究,结果表明:μ值随着粉体粒度的减小而减小,随着压力增大而增大;磁粉的粒径变小,粉芯的Bm值上升,Hc值增大;随着压力增大,粉芯的Bm值上升,Hc值则呈下降趋势。粉体粒度的变化对Q值影响不大。磁粉芯的中心频率为10MHz,其最大Q值为20。软磁粉芯在10MHz左右高频范围内,具有较好的应用价值。     

改善软磁合金热处理后综合性能的方法研究

理论分析和试验验证了热应力对软磁合金热处理后尺寸精度的影响和机加应力对磁性能的影响,提出了一种综合改善软磁合金热处理后磁性能和尺寸精度的方法:对软磁合金材料先半精加工,单边留量0.05mm,再进行磁性热处理,符合磁性能要求后精加工,并留一定的公差余量,最后进行磁性恢复热处理。该方法在保证软磁合金材料零件高尺寸精度的同时,可将机械加工引起的磁性能损失恢复36%～91%,使零件加工的合格率提高一倍左右。     

Nb添加对Fe-Y-B合金非晶形成能力和磁性能的影响

利用单辊快淬法制备了Fe74Y6-xNbxB20(x=0,1,2,3,4)非晶合金条带,利用XRD、HRTEM、DTA和VSM对样品的结构、非晶形成能力和磁性能等进行了测试。结果表明:Fe74Y6–xNbxB20(x=1,2,3,4)合金系的饱和磁化强度Ms>104 A.m2/kg,矫顽力Hc<1.59 kA/m,显示出良好的软磁性能。添加微量Nb扩大了非晶合金的过冷液相区,当Nb含量为摩尔分数1%时,过冷液相区Tx=63℃,此时合金具有最大的非晶形成能力,同时具有最大的饱和磁化强度(Ms=133 A.m2/kg)和最低的矫顽力(Hc=1.27 kA/m)。     

磁控溅射法制备Ag/FePt/C/FePt薄膜的结构和磁性能

采用磁控溅射法,在自然氧化的Si(001)基片上沉积了Ag/FePt/C/FePt纳米薄膜,并分别在400,450,500,600℃下对薄膜样品进行了1h的退火热处理。利用X射线衍射仪和振动样品磁强计,对薄膜样品的结构和磁性进行了分析。结果表明,当热处理温度为450℃时,Ag/FePt/C/FePt薄膜中已形成了具有有序面心四方结构的L10-FePt。随着热处理温度的升高,薄膜样品的有序化程度提高,矫顽力Hc增强,晶粒尺寸变大。当热处理温度为600℃时,薄膜样品的平行膜面Hc为905.8kA·m-1,晶粒尺寸为23nm。     

Nd—Fe—B双相复合永磁合金快淬带结构与显微分析

利用扫描电子显微镜和X射线衍射仪研究了双相复合永磁合金快淬带的结构与形貌。结果表明合金快淬带自由面存在择优取向。与三元Nd-Fe-B合金相比，复合添加Dy和Ga具有增加合金快淬带织构和细化组织形貌的作用。     

Fe-Cr-Si-B非晶磁粉芯的制备与磁性能研究

以水雾法制备的Fe-Cr-Si-B非晶合金粉末为原料制备了非晶磁粉芯,研究了退火温度和成型压力对磁粉芯性能的影响。结果表明:Fe-Cr-Si-B合金粉末具有较高的非晶化程度和良好的热稳定性;当退火温度低于非晶合金的起始晶化温度时,非晶磁粉芯的起始磁导率μi在440℃附近达到峰值44.7,对应的损耗则相对最低(260×10–3W/cm3,50 kHz);当成型压力由30 MPa增大到50 MPa时,磁粉芯的μi由38.6增大到46.4,其损耗则逐渐降低。     

激光晶化制备Fe基纳米软磁材料的研究进展

综述了激光非晶晶化制备Fe基纳米软磁材料的国内外研究进展和现状.介绍了Fe基纳米软磁材料的双相组织结构和性能特征及应用领域;对比分析了传统退火晶化和激光晶化制备技术的优缺点;阐述了研究激光纳米晶化技术的重要意义和理论价值.提出了激光晶化技术制备Fe基纳米软磁材料需要重点系统研究的课题和方向.     

TiO2对铁基合金激光熔覆层组织和性能的影响

在 4 5 #钢基底上进行了铁基合金和铁基合金加TiO2 的激光熔覆对比实验。采用渗透法观察熔覆层表面裂纹 ,利用金相显微镜和扫描电镜观察熔覆层横断面的显微组织 ,使用X射线衍射仪对熔覆层进行物相分析 ,并测试了熔覆层横断面的硬度分布和熔覆层的摩擦磨损性能。结果表明 ,在一定的工艺条件下 ,添加适量的TiO2 ,可以获得成形良好、无裂纹、组织致密均匀、耐磨性好的高质量铁基激光熔覆层。适量的TiO2 可使涂层共晶体数目增多且分布均匀 ,组织细化 ,裂纹消失 ,在降低涂层裂纹敏感性的同时仍保持涂层的硬度和耐磨性不降低。TiO2 对铁基熔覆层性能改善的原因是 :适量TiO2 的加入 ,在涂层中可形成Cr13Fe35Ni13Ti7金属间化合物 ,熔覆层组织由亚共晶组织转变为性能较好的伪共晶组织 ,且由于高熔点的Ti硼化物的析出 ,提高了形核率 ,使组织颗粒细化、均匀。     

Structure and soft magnetic properties of Fe-Co-Ni-based multicomponent thin films

Soft magnetic thin films with suitable uniaxial anisotropy and high saturation magnetization are required for high frequency applications, since the ferromagnetic resonance frequency (f_FMR) is proportional to the multiplication of the saturation magnetization and anisotropy magnetic field. In this study, multicomponents of Fe-Co-Ni-based soft magnetic thin films were deposited on the Si substrate by radio frequency (RF) magnetron sputtering with various Ar/N₂ ratios at room temperature. The composition, crystal structure, surface morphology, and magnetic domain were analyzed. Without nitrogen doping, the domain of the magnetic thin film was arranged randomly. The effect of N₂ content in the thin film on the magnetic properties was evaluated and further discussed. Magnetic properties, including saturation magnetization (M_s) and coercivity (H_c), were determined. The saturation magnetization of the undoped magnetic thin film was around 1.3 T. However, when the nitrogen was added, the magnitude of the anisotropy field could reach 30 Oe, while the saturation magnetization was around 1 T. It is expected that the derived magnetic thin film is a promising candidate for potential usage in high frequency inductors.     

Ba_xNi_(1–x)La_yFe_(12–y)O_(19)铁氧体的制备与磁性能研究

首先利用溶胶-凝胶法制备了BaxNi1–xFe12O19(x=0.2,0.4,0.6,0.8)样品,通过热重-差示扫描量热仪(TG-DSC)、X射线衍射仪(XRD)和振动试样磁强计(VSM)分析,确定了最佳煅烧温度和最佳Ba-Ni摩尔比。然后利用同样的方法制备了Ba0.6Ni0.4LayFe12–yO19(y=0,0.1,0.3,0.5)样品,利用场发射扫描电镜(FESEM)、XRD和VSM对产物进行表征分析。结果表明Ni2+取代Ba2+,进入其晶格内部,改变了铁氧体的磁性能。La3+的加入改变了铁氧体的矫顽力Hc、饱和磁化强度Ms和剩余磁化强度Mr。当y=0.3时,其Ms和Mr达到最大值,分别为51.0 A.m2/kg和32.3 A·m2/kg。     

Structures and physical properties of sputtered amorphous SiC films

Optical and electrical properties have been measured for amorphous SiC films prepared by rf sputtering in a pure Ar atmosphere with a sintered 6H-SiC target. The absorption edge E₀ determined from the relation of αhΝ = B(hΝ-E₀)² ranged from 1.45 to 1.80 eV depending on the film thickness and the substrate temperature. The room temperature electrical conductivity is in the range of 5.4×10⁻¹¹ and 1.4×10⁻⁵ Ω⁻¹cm⁻¹. The absorption edge decreases and the conductivity increases with increasing film thickness. The absorption edge shifts to shorter wavelengths (blue shift) and the conductivity decreases during annealing below 400‡C for 60 min, whereas the absorption edge shifts to the longer wavelength side (red shift) and the conductivity increases during annealing at 800‡C It is proposed that the two annealing processes cause structural changes in amorphous SiC films, one of which involves removal of defects or voids while the other involves rearrangement or rebonding of the component atoms.     

非晶丝MI效应磁场方位角测量系统

本文利用双轴MI效应设计并制作了一种磁场方位角测量系统。分析了尖脉冲电流激励下MI效应,并设计CMOS多谐振荡电路产生尖脉冲电流对非晶丝激励,制作成灵敏度高、稳定性好、功耗低的磁场传感器。利用LabVIEW软件,方便地实现磁场方位角的计算以及数字化显示。     

Microstructure of amorphous and crystalline electrodeposited Ni-P and Co-P alloys

A new model for the microstructure of electrodeposited Ni-P and Co-P alloys is presented based upon the concept of grain boundary segregation. The model correctly explains the compositional dependence of grain size as well as other experimental data. The model also predicts an anomalous low temperature heat capacity and a low temperature resistivity minimum. Both these predictions are confirmed experimentally. Research supported by NSF, Engineering Materials Program. Based upon Ph.D. Thesis of Y. Tyan, Univ. of Minn., 1973.