P2O3—B2O3—Al2O3—SrO—BaO玻璃中的Yb^3＋非辐射能量转移下E …

本文研究了共掺Ｅｒ＾３＋／Ｙｂ＾３Ｐ２Ｏ３－Ｂ２Ｏ３－Ａｌ２Ｏ３－ＳｒＯ－ＢａＯ玻璃的能量转移过程。实验中制备了高掺杂Ｂｂ＾３＋离子的双掺Ｅｒ＾＃＋／Ｙｂ＆＾３＋的磷酸盐玻璃样品。在Ｅｒ＾３＋／Ｙｂ＾３＋掺杂比率〉１：１８（ｍｏｌ％）时,观测到了基于Ｙｂ＾３＋离子至Ｅｒ＾３＋离子能量转移下Ｅｒ＾３＋（＾３Ｉ１３／２→＾４Ｉ１５／２）的增强发射和ｂ＾３＋（＾２Ｆ７１／→＾２Ｆ５／２）发射的减弱,当Ｂ     

NH3／H2O—LiBr为工质的压缩／吸收式循环

为了寻找压缩／吸收式循环中比ＮＨ３／Ｈ２Ｏ性能更好的工质，对三元混合工质ＮＨ３／Ｈ２Ｏ－ＬｉＢｒ进行了热力计算，预计ＮＨ３／Ｈ２Ｏ－ＬｉＢｒ对于该类循环具有良好的热力性能。之所以选择ＮＨ３－Ｈ２Ｏ－ＬｉＢｒ的原因是该混合物已经有了一些实验数据，三元混合工质中质量浓度直至６０％范围，计算了循环的综合特点与性能。当热物性数据不能直接从测试中获得时，采用计算的办法得出，将这处三元混合工质的特性与ＮＨ３／     

c取向YBa2Cu3O7—δ超导外延膜进脱氧过程

用电阻法测量了ＹＢａ２Ｃｕ３Ｏ７－δｃ取向外延膜进脱氧过程,结果表明在氧含量变化较小的情况下,进氧、脱氧速率相近,用Ｘ射线衍射方法证明了ＹＢａ２ＣＵ３Ｏ７－δｃ取向外延膜电阻率与氧含量成指数关系,获得氧化学扩散激活能久为０．９ｅｖ。     

NH3／H2O—LiBr为工质的压缩／吸收式循环（下）

为了寻找压缩／吸收式循环中比ＮＨ３／Ｈ２Ｏ更好的工质，对三元混合工质ＮＨ３／Ｈ２Ｏ－ＬｉＢｒ的循环进行了热力计算，三元混合工质对于该类循环具有良好的热力性能，之所以选择ＮＨ３／Ｈ２Ｏ－ＬｉＢｒ是因为该混合物已有一些实验数据。     

（WC—Co／NiCrBSi）钎焊涂层结合机制及磨损性能研究

采用真空钎焊工艺,将ＷＣ－Ｃｏ硬质合金粉和ＮｉＣｒＢＳｉ（ＡＷＳＢＮｉ－２）合金粉钎焊到４５＃钢表面,得到（ＷＣ－Ｃｏ／ＮｉＣｒＢＳｉ）钎焊涂层。     

Co—Cr合金膜的X射线线形分析

利用近池数法对Ｃｏ－Ｃｒ合金薄膜的衍射线性形进行分析，并提出用“三线法”确定衍射线的函数类型及其积分宽度，由此可计算薄膜的晶粒尺寸和微观应变。理论计算和实验表明，“三线 法”结合近似函数在线形分析方面是简便，可靠的。通过分析Ｃｏ－Ｃｒ膜在不同工艺条件下（膜厚、Ａｒ工作气体压强和负偏压）的衍射线线形，发现衍射线的物理展宽（即有效晶粒尺寸的减小）是粒取向度的下降是相应的，晶粒取向度的下降与结构缺陷密度     

操作条件对化学镀Co—P薄膜磁性的影响

用ＡＳＭ－ＳＸ、ＤＸＳ－１型扫描电镜、Ｄｍａｘ／ｒＢ旋转阳极Ｘ射线衍射仪和Ｈ－８００型透射电子显微镜分析观察了化学镀Ｃｏ－Ｐ镀层的成分、组织结构和表面形貌，并用７１型显微硬度计测量了其硬度，用ＬＤＪ－９０００型振动磁强计测定了膜层的矫顽力和矩形比。研究结果表明：化学镀Ｃｏ－Ｐ镀层为晶态，是磷在钴中形成的过饱和溶液，组织中有大量层错；该镀层具有较高矫顽力和矩形比，适宜作磁记录介质，膜层的易磁化方向与     

钎焊工艺对WC—Co／NiCrBSi复合涂层性能的影响

采用真空钎焊技术,在４５＾＃钢基体表面焊一层（ＷＣ－Ｃｏ／ＮｉＣｒＢＳｉ）复合涂层,研究了不同钎焊工艺对涂层自身结合强度、涂层与基体间连接强度以及涂层抗磨料磨损性能的影响。钎焊工艺为１０８０℃×１０ｍｉｎ时,涂层自身结合强度为１４６ＭＰａ;涂层与基体间的最高连接强度为３６７ＭＰａ。涂层的抗磨料磨损性能比Ｃｏ－Ｃｒ－Ｗ堆焊涂层和（ＷＣ－Ｃｏ／ＮｉｒＢＳｉ）火焰堆焊层的高。     

Bi—V—Cr系复合氧化物的制法及其热色特性

报道了新型可塑热色材料Ｂｉ－Ｖ－Ｃｒ复合氧化物的制取方法及热致变色特性，实验表明，ＢｉＶＯ４可在黄（室温）－橙（１２０℃）－红（１２００℃）色系可逆变色；ＢｉＣｒＯ３可在绿（室温）－黄（１４０℃）色系可逆变色；Ｂｉ－Ｖ－Ｃｒ混合晶体氧化物可在黄绿Ｐ室温－黄袍（１２０℃－深褐（１８０℃）色系可逆变色。     

NH3／H2O—LiBr为工质的压缩／吸收式循环（上）

为了寻找压缩／吸收式循环中比ＮＨ３／Ｈ２Ｏ更好的工质，对三元混合工质ＮＨ３／Ｈ２Ｏ－ＬｉＢｒ的循环进行了热力计算。三元混合工质对于该类循环具有良好的热力性能。之所以选择ＮＨ３／Ｈ２Ｏ－ＬｉＢｒ是因为该混合物已有一些实验数据。对三元混合工质中盐的质量浓度直至６０％的范围内计算了该循环的一般特点与性能，当其热力性能数值不能直接从测试中得到时，采用计算的办法得到。     

烧结NdFeB永磁材料取向度的定量计算

本文在分析烧结NdFeB取向度的各种计算方法的基础上，提出一种新的计算方法。采用这种方法，仅利用烧结体垂直于外加磁场方向截面的X射线衍射谱，通过简单的计算就能很容易的计算出磁体的取向度。     

添加润滑剂对烧结钕铁硼磁体性能的影响

研究了烧结钕铁硼永磁材料的粉末流动性及添加润滑剂对粉末流动性与磁体取向度和磁性能的影响.结果表明:影响松装状态磁粉流动性的主要因素是粉末颗粒团聚,影响密实磁粉流动性的主要因素是颗粒间的摩擦力.添加适量的润滑剂可以防止粉末颗粒团聚、明显地减小摩擦力,改善粉末流动性,提高磁体的取向度、剩磁与磁能积.采用添加润滑剂和橡皮模等静压制成型工艺,批量生产的烧结钕铁硼磁体性能达到:Br=1.457 T,jHc=1148 kA/m(14.43 kOe),(BH)max=408 kJ/m3(51.3 MGOe).     

回收制备烧结Nd-Fe-B磁体的磁性能与耐热性能

以废旧钕铁硼磁体为原料,采用短流程回收制备技术制备了烧结Nd-Fe-B磁体,通过添加镨钕混合稀土研究了磁体的磁性能和耐热性能.结果表明,在回收磁体中添加2％ PrNd,制备的烧结Nd-Fe-B磁体的剩磁为1.31T、矫顽力为1 474.86 kA/m、磁能积为353.90 kJ/m3.与一次成品相比矫顽力恢复到102％,剩磁恢复到95％,磁能积恢复到90％.在293～393 K范围内未掺杂PrNd磁体的矫顽力温度系数为-0.589 9％/K,掺杂2％PrNd磁体的矫顽力温度系数为-0.556 4％/K,提高了磁体在高温下的耐热性能.这是由于添加混合稀土PrNd增强了主相晶粒间的去磁交换耦合作用,提高了主相的磁晶各向异性场,从而提高了磁体的矫顽力和耐热性能.     

Intergrain Interaction, Coercivity and Henkel Plot for NdFeB Magnets

For both sintered and nanocomposite NdFeB magnets, deltaM(H) of the Henkel plot increases from zero, and reaches a peak, then decreases and changes to the negative values with increasing applied field. This shows that the intergrain interaction changes from the exchange-coup ling type into the magnetostatic interaction type. The magnetic field corresponding to the peak of deltaM(H) is slightly smaller than the coercivity of magnet. The peak of deltaM(H) for aligned sintered magnet is greater than that for misaligned magnet. deltaM(H) peak of the nanocomposite NdFeB magnets increases with decreasing grain sizes. It indicates that the effect of alignment field on the properties of magnet is similar to that of exchange-coupling interaction.     

Anisotropic Fracture Behavior of Sintered Rare-Earth Permanent Magnets

Sintered rare-earth permanent magnets (for example, Sm$_2$Co$_17$, SmCo$_5$, and Nd$_2$Fe$_14$B magnets) are quite brittle and easily crack in the course of fabrication, machining, and application. Here, we report on an investigation of fracture behavior and mechanical characteristics of sintered rare-earth permanent magnets and discuss the origin of rare-earth magnet brittleness. We studied three groups of bending specimens with different orientations, cut from the same block of magnet. The bending strength was measured. The fracture surfaces were carefully observed by scanning electron microscopy and showed that the fracture behavior and bending strength of sintered rare-earth permanent magnets obviously exhibit anisotropy. Sintered Sm–Co magnets tend to cleavage fracture in the close-packed ($0001$) plane or in the ($10bar11$) plane. The fracture mechanism of sintered Nd$_2$Fe$_14$B magnet appears to be mainly intergranular fracture. Our analysis indicates that the anisotropy of fracture behavior and mechanical strength of sintered rare-earth magnets is caused by the strong crystal-structure anisotropy and grain texture created by magnetic field alignment during the fabrication process.     

Use of paired, bonded NdFeB magnets in redox magnetohydrodynamics

Bonded neodymium-iron-boron (NdFeB) permanent magnets in a paired configuration were successfully used to control mass transport in redox-based, magnetohydrodynamics (MHD). Control of fluid flow based on magnetic fields has potential for use in portable lab-on-a-chip (LOAC) and analytical devices. Bonded magnets, composed of magnetic powder and organic binder materials, are less expensive and easier to fabricate and pattern than electromagnets and sintered permanent magnets, which have been previously used in MHD studies on electrochemical systems. The ability to pattern bonded magnets near and around the electrodes is expected to allow for better control over the magnetic field distribution and solution flow. Current was generated at an 800-microm-radius platinum disk electrode in a solution of 0.06 M nitrobenzene and 0.5 M tetra-n-butylammonium hexafluorophosphate in acetonitrile. Increases in limiting current in the presence of the magnetic field, which indicate enhancement in mass transport, for sintered (210+/-14%, N = 4, where B(r) = 1.23 T and magnetic field strength is 0.55 T) and bonded (94+/-8%, N = 4, where B(r) = 0.41 T and magnetic field strength is 0.20 T) magnets, were similar to those obtained using an electromagnet with the same magnetic flux densities. The magnetic field strength and not the magnet type is important in controlling fluid flow, which is encouraging for integration of bonded permanent magnets into LOAC devices.     

粉末注射成形技术在烧结NdFeB永磁体制备中的应用

全面介绍了采用注射成形技术制备烧结NdFeB永磁体的工艺过程；总结了粘结剂、磁场取向及成形、脱脂和烧结工艺对最终产品的影响；比较了注射成形和传统粉末冶金压制成形制备的NdFeB磁体的性能；在分析现状的基础上，指出了现阶段存在的问题。     

Imaging domains of hard magnetic materials by SEM and MFM

The paper deals with observation of the magnetic domain structure of hard magnetic materials by the colloid-scanning electron microscopy (colloid-SEM) technique and the magnetic force microscopy (MFM) method. The specimens studied were anisotropic sintered Nd-Fe-B-based and SmCo₅ magnets, produced by powder metallurgy route. Observations of the magnetic microstructure were carried out in the thermally demagnetized state of the magnets at the surface perpendicular to the alignment axis. The domain structure is of complicated character. The coarse domain pattern consists of the main domains (forming a maze pattern near the specimen surface) and surface reverse spikes. Besides the coarse domain structure, the presence of fine scale surface domains is revealed by MFM.     

烧结NdFeB磁体的晶粒取向和矫顽力的角度关系

本文研究了烧结ＮｄＦｅＢ磁体的晶粒取向矣矫顽力的影响和矫顽力的角度关系，结果表明：晶粒的混乱取向使矫顽力上升而不是下降，矫顽力的发动场理论比成核机制和钉扎机制与实验结果符合更好。     

放电等离子烧结制备高性能热变形Nd-Fe-B磁体

使用放电等离子烧结(SPS)可在短时间内将非晶Nd13.5Fe80.5B6粉末晶化,且可获得接近于全致密的各向同性磁体,其剩磁、矫顽力、最大磁能积分别为Br=0.8T,Hci＝1346kA/m,(BH)m=108kJ/m3.热变形后,随变形量的增加,硬磁相晶粒的取向度增加,Br及(BH)m大幅增加,在65%时达最大:B...