关于汽车内外饰件塑料成型模具的研究

约90%的汽车内外饰塑料零件是通过塑料模具生产的,汽车工业的快速发展促使塑料模具技术向高效生产、环保制造、高品质外观、以塑代钢等方向发展,如低压一体注塑模具、注塑后压模具、搪塑模具、发泡模具、快速模具等。     

表面扩渗稀土（La,Ce）对1Cr18Ni9钢晶间腐蚀性能的影响

采用硝酸－硫酸铁腐蚀试验，扫描电镜（ＳＥＭ），电子探针（ＥＰＭ）等方法研究了气相扩渗稀土（Ｌａ，Ｃｅ）对１Ｃｒ１８Ｎｉ９钢晶间腐蚀性能的影响，结果表明，扩渗后钢表面几乎不存在贫Ｃｒ区，耐晶间腐蚀性能明显改善，超吉经稳定化处理的１Ｃｒ１８Ｎｉ９Ｔｉ钢水平。     

La,Pr改性ZnO导电粉的制备

为了提高ZnO的导电性,采用稀土气相扩渗法对ZnO粉体进行了La,Pr改性.采用X射线衍射分析、扫描电子显微镜、差热分析和电阻测试仪,对改性前后ZnO组成、结构及电性能的变化进行了研究.XRD测试结果表明:La扩渗后,在29.5°出现了一个与La有关的特征峰,Pr扩渗后,在30.5°出现了一个与Pr有关的特征峰,证明La,Pr已渗入ZnO粉体.SEM测试结果表明:ZnO粉体经La,Pr扩渗后晶粒明显细化,团聚现象减弱.热重分析表明:经稀土扩渗后的ZnO粉体具有较好的热稳定性.La,Pr扩渗后ZnO粉体的室温电阻率由1014Ω.cm分别下降到1.6×106Ω.cm和1.9×106Ω.cm,说明La,Pr扩渗可明显改善ZnO粉体的导电性能和应用性能.     

Y含量对18CrMnB齿轮钢表面粉末包埋渗Nb层性能的影响

为进一步优化18CrMnB齿轮钢的渗Nb工艺,以18CrMnB齿轮钢为基体,通过掺杂稀土 Y的固体粉末包埋法在其表面制得Nb渗层,测试了渗层组织结构、性能与稀土 Y加入量(质量分数)之间的关系.结果表明:当在渗层中添加稀土元素后,得到了外形规则的颗粒,并且大部分颗粒的尺寸都很细小,形成了致密的组织结构.还可以看到夹杂着许多Al2O3,确保渗层可以跟基体形成紧密结合.当Y加入量提高后,Nb渗层的硬度先增高后降低,加入1％的稀土时获得了最高硬度.渗层都主要由NbC构成,还有部分Y2O3组织.加入稀土后渗层具有更低的摩擦系数,加入1％稀土时渗层达到了最小的摩擦系数.加入稀土后得到的渗层具有更低的摩擦系数,渗层表面较为光滑,并且其组织也比较致密.     

3Cr2W8V钢稀土硼铝共渗工艺和性能研究

研究了3Cr2W8V钢稀土硼铝共渗工艺,渗层组织和性能.结果表明,采用文中所述共渗工艺,可在模具的工作带上形成一层高性能的共渗层,渗层表面硬度可达1800～2000HV,取得良好效果.     

钢的稀土氮碳共渗技术研究进展

稀土元素对氮碳共渗渗层的硬度、耐磨性等性能的提高起到了积极的作用,稀土在氮碳共渗中的作用及相关机理有待进一步研究。通过参考现有国内外报道的试验及机理研究,对钢的稀土氮碳共渗的发展过程、类型及稀土的加入方式、在共渗过程中的作用机理、对渗层及基体力学性能的影响进行了综合分析和总结。对钢的稀土氮碳共渗存在的问题进行了探讨,并给出了一些建议。     

稀土—硼共渗层耐酸蚀性能的研究

运用电化学法和失重法对低碳钢稀土－硼共渗层在强酸介质中对耐蚀性进行了研究，结果表明稀土－硼共渗可大大提高低碳钢的耐蚀性。     

稀土对1Cr18Ni9钢腐蚀性能及组织状态影响

利用化学法对1Cr18Ni9钢表面扩渗稀土,通过X－射线衍射分析了试样表面的组织状态。结果表明,1Cr18Ni9钢渗入稀土后,表面有CeFe7和LaO新相产生,并引起奥氏体含量降低,铁素体含量增加,改变了试样表面的微观结构。阳极极化曲线的测定结果表明,扩渗稀土后的1Cr18Ni9钢试样耐腐蚀性能超过了稳定化处理的1Cr18Ni9Ti钢水平。     

模具钢稀土硼铝共渗的研究和应用

研究了3Cr2W8V钢稀土硼铝共渗工艺，试验表明，共渗层具有高硬度（HV1800－2000），低脆性和良好的耐磨等性能，通过实际应用，取得良好效果。     

K7CuBW11O39杂多配合物气相渗铕的热敏性能及交流阻抗谱分析

对K7CuBW11O39导电材料进行了Eu的气相扩渗,研究了扩渗前后材料的导电性能.根据材料的TG-DTA测试结果确定了稀土扩渗的温度,扩渗后经ICP分析测试表明,微量的Eu可渗入到试样中.利用交流阻抗法对扩渗前后的材料分别进行了导电性能的测试,结果表明扩渗后试样的电导率比扩渗前的电导率提高了4.07×104倍.分析电导率与温度的变化关系曲线,发现此材料在450K附近具有类似PTC特性.交流阻抗分析表明材料为离子导体.     

Application of Rare Earths in Thermal Barrier Coating Materials

Rare earths are a series of minerals with special properties that make them essential for applications including miniaturized electronics, computer hard disks, display panels, missile guidance, pollution controlling catalysts, H2-storage and other advanced materials. The use of thermal barrier coatings （TBCs） has the potential to extend the working temperature and the life of a gas turbine by providing a layer of thermal insulation between the metallic substrate and the hot gas. Yttria （Y203）, as one of the most important rare earth oxides, has already been used in the typical TBC material YSZ （yttria stabilized zirconia）. In the development of the TBC materials, especially in the latest ten years, rare earths have been found to be more and more important. All the new candidates of TBC materials contain a large quantity of rare earths, such as R2Zr207 （R=La, Ce, Nd, Gd）, CeO2-YSZ, RMeAI11019 （R=La, Nd; Me=Mg, Ca, Sr） and LAP04. The concept of double-ceramic- layer coatings based on the rare earth materials and YSZ is effective for the improvement of the thermal shock life of TBCs at high temperature.     

真空蒸馏法综合回收稀土熔盐电解渣工艺研究

针对目前稀土熔盐电解渣中稀土、氟、锂综合回收率低的问题,研究开发了真空蒸馏处理稀土熔盐电解渣新工艺,考察了真空蒸馏温度、时间、真空度、原料粒度对稀土熔盐电解渣分离效果的影响。研究结果表明,在较优工艺条件下,F脱除率高达99.6%,氟化物回收率高达95.5%。与传统处理工艺相比,新工艺极大地缩短了工艺流程,且实现了渣中稀土、氟、锂资源的绿色高值利用。     

Crystallisation effects on rare earth dopants in oxyfluoride glass ceramics

Transparent oxyfluoride glass-ceramic materials are of significant interest for the production of new optoelectronic devices. In this paper we report measurements of the detailed spectroscopy of rare earth dopants in both an oxyfluoride transparent glass ceramic and its glass precursor. We show that several spectroscopically different sites exist for the rare earth even in the glass precursor material, where a significant amount of the rare earth is already coordinated with fluorine. In the glass-ceramic material, these glassy fluorine-coordinated sites are replaced with crystalline sites, but a significant fraction of the rare earth ions are still within the glass phase. The fraction of rare earth ion that is incorporated into the crystalline phase is estimated from the rare earth spectroscopy, and the role of the rare earth coordination in the precursor glass is discussed.     

Preparation of Rare Earth Hydroxide and Oxide Nanoparticles by Precipitation Method

A series of rare earth hydroxide and oxide nanoparticles have been prepared by precipitation method with alcohol as the dispersive and protective reagent. Transmission electron microscope (TEEM) images indicate that the particles are spherical in shape and smaller than 100 nm in size. The crystallite sizes of cubic Ln2O3 have lanthanide shrinking effect, while average crystal lattice distortion rates possess lanthanide swelling effect. The diffraction peak intensity of heavy rare earth oxide nanometer powders is remarkably stronger than that of light rare earth oxide nanometer powders. The variation of diffraction intensity with atomic number presents an inverted W type, forming a double peak structure. Fourier transform infrared (FTIR) spectrums reveal that Ln2O3 nanopowders have higher surface activity than that of ordinary Ln2O3 powders. The UV-vis spectra show that Ln-O bond of these particles is slightly blue-shifted, and its absorption intensity decreases.     

稀土在过共晶高硅铝合金中的合金化作用

运用力学性能测试、金相显微镜、扫描电镜研究了稀土在含硅量约为２２％的过共晶Ａｌ－Ｓｉ合金中的合金化作用。结果表明，稀土可作为合金元素替代昂贵金属Ｎｉ，；稀土与Ｃｕ，Ｍｇ，Ｆｅ，Ｓｉ等形成的稀土化合物产生的第二相强化是改善合金高温拉伸性能的主要原因，稀土对合金的强化作用存在一个稀土的最佳含量范围。     

Effects of rare earth additions during surface boriding on microstructure and properties of titanium alloy TC21

Abstract

In the present paper, the effects of rare earth (RE) additions to the solid state boriding of titanium alloy TC21 have been studied. The microstructural evolution and phase transformations of the borided layers were examined using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction. Moreover, the microhardness for the borided layer was also determined by Vickers hardness test. The results showed that the addition of a small amount of RE elements in the boriding process can lead to an increased boron concentration in the surface layer coupled with the improved surface hardness and coating layer thickness. Furthermore, the presence of trace quantities of RE oxide (Ce₂O₃) in boride layers indicated that the RE elements as catalysts could not only influence but also accelerate boriding process.     

Magnetoresistance effect in thin films of Eu1−xSmxO on silicon

In the present study, the temperature-dependence of magnetic field effect on the resistance of films of oxides of rare earth elements (Gd, Eu, and Eu-Sm solid solution) prepared by vacuum thermal evaporation was considered and analyzed at approximately the Curie temperature. It was demonstrated that the temperature range of the effect, its sign and magnitude are determined by the dependence of the magnetic moment of magnetic clusters on both the external magnetic field strength and film parameters such as the spin of the magnetic ion, exchange energy, defect density, etc.     

Characterisation of high purity rare-earth oxides by x-ray fluorescence methods

X-ray fluorescence methods for the determination of individual rare earth impurities in high purity rare earth oxidesviz., Y₂O₃, La₂O₃, CeO₂, Pr₆O₁₁, Nd₂O₃, Sm₂O₃, Eu₂O₃, Gd₂O₃, Tb₄O₇, Dy₂O₃, Ho₂O₃ and Er₂O₃ have been developed in our laboratory. The samples are converted to oxalate form and double-layer pellets are prepared using boric acid as binding material. A semiautomatic x-ray spectrometer is used for the analyses. Choice of instrumental parameters and analysis lines is discussed. The determination range varies from 0.005% to 1.0% for most elements with good precision and adequate accuracy.     

稀土在银基接触材料中的作用与应用

介绍了稀土在银及银合金电接触材料中的作用、特点及影响效果,阐述了国内外稀土银合金电接触材料的应用情况,展望了稀土银合金的发展前景。     

混合稀土对AZ91镁合金在NaCl溶液中的腐蚀行为影响

通过静态失重法、极化曲线和交流阻抗测试研究了混合稀土 (Re)对AZ91镁合金腐蚀行为的影响。结果表明 :Re的加入使AZ91微观组织得到改善 ,减缓了AZ91镁合金在NaCl溶液中的腐蚀