焦耳处理对Fe73.5Cu1Nb3Si13.5B9合金丝巨磁阻抗效应影响的研究

研究了焦耳处理对Fe73.5Cu1 Nb3Si1 3.5B9非晶丝巨磁阻抗 (GMI)效应的影响。结果表明 ,Fe73.5Cu1 Nb1 3.5Si3B9非晶丝的GMI效应对处理工艺很敏感 ,淬态样品在 3 40MPa拉应力下 ,经 5 3A·mm- 2 的直流电流处理后 ,其阻抗相对变化率达到 68% ,灵敏度达 0 86% A·m- 1 。优异的软磁性能和环型各向异性是获得巨磁阻抗效应的关键因素。     

焦耳处理和等温退火对Fe73.5Cu1Nb3Si13.5B9非晶丝巨应力阻抗效应的影响

研究了焦耳退火和等温退火对Fe73.5Cu1Nb3Si13.5B9非晶丝巨应力阻抗效应的影响. 实验结果表明, 非晶合金丝经电流密度为 26 A*mm-2的焦耳处理后, 其阻抗最大变化率达到25%, 灵敏度为1.71%*MPa-1; 淬态样品在580 ℃等温退火0.5 h后, 其阻抗最大变化率达到67%, 灵敏度为0.85%*MPa-1. 这两种退火方法都可以明显改善Fe73.5Cu1Nb3Si13.5B9非晶合金丝的巨应力阻抗效应, 阻抗的最大变化率与退火过程中晶化导致的平均各向异性的改变有关, 而灵敏度的差异是由退火方法导致材料机械性能的差异带来的.     

焦耳处理和等温退火对Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9非晶丝巨应力阻抗效应的影响

研究了焦耳退火和等温退火对Fe73.5Cu1 Nb3Si1 3.5B9非晶丝巨应力阻抗效应的影响。实验结果表明 ,非晶合金丝经电流密度为2 6A·mm- 2 的焦耳处理后 ,其阻抗最大变化率达到 2 5 % ,灵敏度为 1 71%·MPa- 1 ;淬态样品在 5 80℃等温退火 0 5h后 ,其阻抗最大变化率达到 67% ,灵敏度为 0 85 %·MPa- 1 。这两种退火方法都可以明显改善Fe73.5Cu1 Nb3Si1 3.5B9非晶合金丝的巨应力阻抗效应 ,阻抗的最大变化率与退火过程中晶化导致的平均各向异性的改变有关 ,而灵敏度的差异是由退火方法导致材料机械性能的差异带来的     

基于Fe73.5Cu1Nb3Si13.5B9非晶/纳米晶粉的压磁复合材料研究

研究了基于Fe73.5Cu1Nb3Si13.5B9非晶/纳米晶粉的柔性压磁复合材料制备技术及其性能, 讨论了橡胶种类, 磁粉粒径、含量及工艺因素等对Fe73.5Cu1Nb3Si13.5B9/橡胶复合材料压磁性能的影响. 结果表明: 采用粒径为45 μm, 用量约15%的Fe73.5Cu1Nb3Si13.5B9非晶/纳米晶粉与高温硫化有规共聚硅氧烷在171 ℃, 15 Mpa条件下, 硫化45 min制备的、厚度约150 μm的压磁复合材料薄膜具有较好的应力敏感特性和压磁稳定性能, 有望作为新一代柔性、薄型接触应力传感器的敏感元件材料.     

Fe73.5 Cu1 Nb3 Si13.5 B9非晶合金的激光晶化

用CO2连续激光在不同功率、相同的速度条件下辐照Fe73.5Cu1Nb3Si13.5B9非晶带，然后用穆斯堡尔谱详细研究材料的微观结构。研究发现当扫描速度和散文斑直径一定的情况下，适当选择激光功率，Fe73.5Cu1Nb3Si13.5B9可以实现微量晶化。     

两段式焦耳处理对Co71.8Fe4.9Nb0.8Si7.5B15非晶薄带巨磁阻抗效应的影响

研究了两段式焦耳处理对Co71.8Fe4.9Nb0.8Si7.5B15非晶薄带巨磁阻抗效应的影响.实验结果表明:经第1段电流密度为15 A/mm2、第2段电流密度为35 A/mm2的复合处理后,样品获得了最大的GMI效应.在8MHz的交变电流频率下,最大磁阻抗比为305%,灵敏度为0.575%/(A·m-1).两段式焦耳处理是提高材料GMI效应的一种新的而且十分有效的方法.     

直流焦耳处理对Co718Fe49Nb08Si75B15玻璃包覆非晶丝非对称巨磁阻抗效应的影响

 研究了Co718Fe49Nb08Si75B15玻璃包覆非晶丝经直流焦耳处理后的非对称巨磁阻抗效应。结果表明，随着处理电流的增加，阻抗最大变化率随之增大，并在处理电流为70 mA时达到最大值。在15 MHz的驱动电流下，阻抗最大变化率为335%，线性区域的灵敏度达1%/(A·m-1)。进一步提高处理电流，导致阻抗最大变化率减小。对钴基玻璃包覆非晶丝的AGMI性能特征用表面阻抗张量进行了讨论。     

直流焦耳处理对Co71.8Fe4.9Nb0.8Si7.5B15玻璃包覆非晶丝非对称巨磁阻抗效应的影响

研究了Co71.8Fe4.9Nb0.8Si7.5B15玻璃包覆非晶丝经直流焦耳处理后的非对称巨磁阻抗效应.结果表明,随着处理电流的增加,阻抗最大变化率随之增大,并在处理电流为70 mA时达到最大值.在15 MHz的驱动电流下,阻抗最大变化率为335%,线性区域的灵敏度达1%/(A·m-1).进一步提高处理电流,导致阻抗最大变化率减小.对钴基玻璃包覆非晶丝的AGMI性能特征用表面阻抗张量进行了讨论.     

Co基非晶丝退火处理及对巨磁阻抗效应

 采用熔体抽拉法制备了直径59μm 的Co68.25Fe4.5Si12.25B15非晶丝，并在400℃、500℃进行了不同工艺的退火处理，分析了退火前后丝的巨磁阻抗（GMI）效应。结果表明，400℃退火处理降低了丝的各向异性场，提高GMI效应以及双峰出现频率，并大幅提高了磁场响应灵敏度。400℃保温20min退火样品双峰出现频率提高至13MHz。400℃保温80min退火样品低频GMI效应最强，最大阻抗变化率△Z/Z达到468.6%，5MHz时磁场响应灵敏度为57.9%/Oe。 500℃退火，由于晶化析出导致GMI效应降低，双峰出现频率降至3MHz。实验表明经适当退火处理的Co基熔体抽拉丝可用以制备高灵敏度磁传感器的磁敏材料。     

Fe-Cu-Nb-Si-B薄带的淬态纳米化与巨磁阻抗效应

使用较低的快淬速度(V =2 2m·s- 1 ) ,可以使Fe Cu Nb Si B薄带实现淬态纳米晶化。Fe Cu Nb Si B薄带析出αFe(Si)纳米相,其晶粒尺寸在淬态薄带Fe73Cu1 .5Nb3Si1 3.5B9中约为15nm ,在Fe71 .5Cu3Nb3Si1 3.5B9中约为10nm。添加Cu元素可以细化淬态薄带的晶粒。实验发现磁阻抗ΔZ/Z0 ,磁电阻ΔR/R0 ,磁电抗ΔX/X0 三条曲线交叉于一点,通过推导发现此现象具有必然性。淬态薄带Fe74 .5-xCuxNb3Si1 3.5B9的磁阻抗显示了较强的Cu含量依赖性。在快淬速度v =2 2m·s- 1 下,在x =1.5和x =3左右观察到磁阻抗峰值现象。     

Superconducting Transition Temperature in YBa2Cu4O8/La2/3 Ca1/3 MnO3 / YBa2 Cu4O8 Heterostructure

YBa2Cu4O8/La2/3 Ca1/3 MnO3/YBa2Cu4O8 （ Y-124/LCMO/Y- 124） heterostructure was prepared by facing-target sputtering technique. The oscillatory superconducting transition temperature was observed when the thickness of LCMO d L is larger than critical thickness d L^CR. The metal-insulator transition temperature can only be detected at d L 〉 d L^CR. The dependence on the spacer layer in LCMO/Y-124 systems suggests strongly the interplay of ferromagnetic and superconducting couplings.     

Visible luminescence of lanthanide ions in Ca3Sc2Si3O12 and Ca3Y2Si3O12

The crystalline materials Ca₃Sc₂Si₃O₁₂ and Ca₃Y₂Si₃O₁₂ were characterized by different crystal structures, as the former is a cubic garnet, while the latter is an orthorhombic compound. We investigated the optical spectroscopy of these materials doped with several trivalent lanthanide ions and compared the results for the two hosts. Polycrystalline samples were prepared by solid state reaction, both undoped and doped with the trivalent lanthanide ions Eu³⁺, Tb³⁺ and Sm³⁺. Emission, excitation and Raman spectra of these materials were measured at temperatures ranging from 300 to 10 K. The optical spectra were assigned and discussed, and the effects of the crystal structure of the host on the spectroscopic behaviour were addressed. The technological potential of these compounds in the field of optical materials and devices was discussed.     

Al2O3La2O3Y2O3/Cu复合材料的电弧侵蚀特性研究

采用喷射沉积和内氧化法制备出Al₂O₃La₂O₃Y₂O₃/Cu复合材料,研究该材料在直流20 V/20 A的工作条件下触点的电弧侵蚀特性,并与Al₂O₃/Cu材料进行了对比分析.利用电子天平、扫描电镜等方法分析电弧侵蚀后触点的质量变化和表面微观结构.结果表明,通过添加Y₂O₃、La₂O₃稀土氧化物颗粒,可有效降低触头材料的材料转移量.Al₂O₃La₂O₃Y₂O₃/Cu材料的抗熔焊性和抗烧损性优于Al₂O₃/Cu材料的性能.在直流阻性负载条件下Al₂O₃La₂O₃Y₂O₃/Cu阳极触头表面形成凹坑,阴极触头表面形成凸起,触点表面显示出浆糊状凝固物和喷发坑等电弧侵蚀形貌特征.      

CaO—SiO2—Na2O—CaF2—Al2O3—MgO保护渣系的Al2O3吸收速率和粘度

采用CaO-SiO2-Na2O-CaF2-Al2O3-MgO渣系,通过测定熔渣的粘度和Al2O3吸收速率,研究连铸保护渣的Al2O3吸收速率与粘度及化学成分之间的关系。在一定条件下,当CaO/SiO2为1.2左右时,粘度达到最小值,Al2O3吸收速率达到最大值,分别为0.10?Pa*s、8.403×10-4?kg*m-2*s-1。随着渣中Na2CO3含量、CaF2含量和MgO含量的增加,粘度减小,Al2O3吸收速率增大。随着渣中Al2O3含量的增加,粘度增大,Al2O3吸收速率减小。粘度为Al2O3吸收速率的主要控制因素。随着熔渣粘度的增加,连铸保护渣的Al2O3吸收速率逐渐减小。     

CaO-La2O3-B2O3-Eu2O3转光玻璃的合成及荧光性质

X射线衍射研究表明CaO-La2O3-B2O3-Eu2O3体系的玻璃化温度在1025℃附近.荧光光谱和ESR谱研究表明,在CaO-La2O3-B2O3-Eu2O3玻璃体系中存在着Eu2+和Eu3+两种价态离子. 316, 360, 379, 394, 413, 462和532nm锐线激发峰和592,616和650红区发射峰分别对应Eu3+的f-f激发跃迁和5D0-7FJ (J=1,2,3)跃迁发射;351nm和427nm宽带激发峰和蓝区发射分别对应Eu2+的5d-4f激发跃迁和发射.     

Fracture Behavior in Cu46.5Zr46.5Al7 and Cu46.5Zr41.5Al7Y5 Bulk Metallic Glasses

The interplay between chemical composition, plastic behavior, and fracture modes of Cu_46.5Zr_46.5Al₇ and Cu_46.5Zr_41.5Al₇Y₅ bulk metallic glasses (BMGs) was investigated by compression tests and fracture surfaces analyses. The aim was to explore the possibility of coupling physical, chemical, and hardness properties, with adequate macroscopic compressive plasticity. Cylindrical test samples, having a height-to-diameter ratio equal to 2, were machined and ground from as-cast bars and were tested in compression between lubricated plates, the displacement being measured by a clip-gage inserted between the plates. Y free BMG engineering stress-strain curves show a plastic behavior consisting of successive sudden stress drops and linear reloading segments. A detailed analysis of these features was performed to yield a correlation between the plastic deformation steps and the released elastic energy associated with each serration.     

Effect of Fe2O3 Loading Amount on Catalytic Properties of Monolithic Fe2O3/Ce0.67Zr0.33O2 -Al2O3 Catalyst for Methane Combustion

Ce0.67Zr0.33O2-Al2O3 solid solution was prepared by the co-precipitation method. Fe2O3-based catalysts supported on the solid solution were obtained by the impregnation method. The article revealed that the optimal loading amount of Fe2O3 on Ce0.67Zr0.33 O2-Al2O3 in our experimental condition for catalytic combustion of methane was 8% （ mass fraction）. The prepared catalysts were characterized by BET, TPR, XRD analyses, and their catalytic activity was investigated after being calcined at 873 K and after being aged in water gas at 1273 K. When the loading amount of Fe203 was 8% （ mass fraction）, the catalyst held the highest activity, and the best temperature speciality and thermal stability. The complete-conversion temperature of methane for fresh and aged sample was 788 and 838 K, respectively. The range between the light-off temperature and the complete-conversion temperature was only 15 K. The characterization results of XRD indicated that Fe2O3 was well dispersed on the Ce0.67Zr0.33O2-Al2O3 matrix. The results of BET and TPR were in good harmony with the catalytic activity results.     

CaO--TiO2--Fe2O3三元系中Ca3TiFe2O8的生成机理

钒钛磁铁矿是烧结矿重要的原料之一,Ca₃TiFe₂O₈作为钒钛烧结矿中矿物被发现之后,其生成机理尚不明确.本文采用X射线衍射分析、元素能谱分析和TG-DSC分析相结合的方法,研究了Ca₃TiFe₂O₈的生成机理以及不同温度、CaO与TiO₂含量下Ca₃TiFe₂O₈的生成规律.实验结果表明,Ca₃TiFe₂O₈由Ca₂ Fe₂O₅和CaTiO₃反应生成,即CaO和Fe₂O₃反应生成Ca₂ Fe₂O₅;其后,与CaTiO₃反应生成Ca₃TiFe₂O₈.反应时间越长,Ca₃TiFe₂O₈的生成量越大,但反应温度对Ca₃TiFe₂O₈生成的影响并不明显.另外,还发现CaO含量越高,Ca₃TiFe₂O₈越易于生成,而且等摩尔Fe₂O₃和CaO下只要存在TiO₂,就会有Ca₃TiFe₂O₈生成.      

Magnetocaloric Effect of Ni56Mn18.8Ga24.5 Gd0.7 Alloy

Inrecent years materials with high magnetocaloriceffect (MCE) have attracted considerable attention ow-ingto its potential application as a magnetic refriger-ant .Many material systemsthat underwentthefirst-or-der magnetic transition have been found to exhibit agiant MCE. Their typical representatives areGd5(SixGe1 -x)4[1 ,2]and La (FexSi1 -x)13[3 ,4]alloys .Ni MnGa is aferromagnetic shaped memory alloy whichundergoes a reversible first-order structural phase tran-sition (SPT) with the …     

Al2O3-V2O5体系的热力学优化

在对Al₂O₃-V₂O₅体系相图、热力学数据以及晶体结构数据进行综述与评估的基础上,采用相图计算方法对Al₂O₃-V₂O₅体系进行热力学优化.液相采用修正的似化学模型进行描述,利用对近似处理液相中存在的短程有序.将液相模型的最大短程有序设置在AlVO₄处,将VO₄3-当作液相中V₂O₅的基本组成单元.体系中AlVO₄相看作线性化合物.计算结果很好的重现了选定的实验数据,获得了一套合理、可靠、自洽的模型参数用来描述体系中各相的热力学性质,为Al₂O₃负载V₂O₅型催化剂催化性能的提高打下坚实的基础.