机械化学法制备ZrO_2∶Eu~(3+)纳米晶及其发光特性

以ZrOCl2·8H2O、EuCl3·6H2O和NaOH为原料,采用机械化学法制备ZrO2∶Eu3+发光粉体。采用透射电镜、X射线衍射仪和荧光光谱仪对其微观形貌、物相和发光特征进行表征。结果表明:ZrO2∶Eu3+发光粉体为分散均匀,粒径约为10nm的纳米晶。主晶相为t-ZrO2,随着煅烧温度的升高,出现少量m-ZrO2。发射光谱为Eu3+在604nm和595nm处的特征发射,分别对应5D0→7F2和5D0→7F1跃迁。m-ZrO2出现导致ZrO2∶Eu3+对称性的下降,在610nm处出现发射峰。Eu3+掺杂量为8mol%时达到最大发光强度。     

CeO2纳米线的合成及影响因素的探讨

采用水热法合成了粒径为25 nm的CeO2纳米线,采用X射线衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)对其进行了表征和观察;同时考察了沉淀剂种类、沉淀剂浓度、分散剂种类和反应时间等因素对纳米线的合成的影响,最终得到合成纳米线的最佳工艺条件为:以氯化铈为铈源,氢氧化钠为沉淀剂,CTAB为分散剂时所合成的纳米线分散性好,粒径均一。讨论了纳米线的影响因素。     

稀土产品的物性控制与稀土产业的发展

本文讨论了稀土材料性能与稀土产品物性间的相关关系,认为稀土产品的物性控制对于发展未来稀土产业将起重要作用,因此建议在现阶段的稀土产业的发展计划中应当体现出物性控制的攻关目标,并就当前国内稀土新产品开发中的问题和大家关注的热点作了相应的介绍     

有机酸类缓冲介质对稀土—偶氮胂Ⅲ显色性能的影响

比较研究了甲酸、乙酸和一氯醋酸三种有机酸溶液对稀土－偶氮胂Ⅲ显色性能的影响，结果表明：在用偶氮胂Ⅲ显色测定稀土时，选择甲酸溶液作缓冲介质最好。     

镧—镍系稀土贮氢材料的应用研究概况

本文综述了国内外镧-镍系稀土贮氢材料的应用研究概括,指出这类材料的工业生产与应用将是稀土应用的又一重要领域。     

稀土PVC塑料热稳定剂的应用前景

介绍了PVC塑料热稳定剂的发展与应用,并对稀土PVC塑料热稳定剂的制备工艺、性能和应用前景进行了详细的论述。     

Preparation of La（OH）3 and La2O3 with Rod Morphology by Simple Hydration of La2O3

Lanthanum hydroxide with rod-like morphology was synthesized with simple hydration processing via the hydration of its bulk oxide in normal water solution at boiling temperature. An XRD pattern shows the formation of the hexagonal phase of La（OH）3, indicating that the hydration process is very rapid. The as-prepared La（OH）3 is almost entirely with a needle- or rod-like shape with a width of 2 - 3 μm and a length of 5 - 8 μm. The mechanism of the formation of La（OH）3 with rod-like morphology was preliminarily presented. It is easier to expand the simple hydration process on a large scale than the hydrothermal process.     

硝酸铁与水杨酸甲酯绿色硝化的选择性及其副产物组成的研究

研究了硝酸铁与水杨酸甲酯的绿色硝化反应。主要产物为3-硝基水杨酸甲酯(O)和5-硝基水杨酸甲酯(P),其选择性与工业化生产比得到了提高,最大比值为P/O=5.3。副产物的组成通过红外光谱、元素分析、差热热重和固体漫反射光谱确定为Fe(NO3)a(MNS)bOc1.8 H2O,其中a+b+2 c=3,随着反应物浓度的增加,a减小b增大。并回收了硝酸铁,其回收率为73.4%(以铁含量为基准)。     

机械化学法制备ZrO2纳米粉体的工艺研究

以ZrOCl2·8H2O和NaOH为原料,采用机械化学法制备ZrO2纳米粉体.研究了前驱体不同处理方法对粒径的影响.采用X射线衍射仪、激光粒度分析仪、比表面积仪、扫描电镜、透射电镜对粉体进行表征.结果表明前驱体经500℃煅烧后出现t-ZrO2,且随温度升高,晶粒尺寸逐渐增大,晶型逐渐完整.采用机械化学法可制备分散均匀、粒径为10 nm的ZrO2粉体,其最佳处理工艺条件是先将前驱体500℃煅烧后再将NaCl洗去.     

Enhancement of photoluminescence of Ba2SiO4：Eu^2＋ by co-doping of La^3＋ or Y^3＋

Green light-emitting Ba2SiO4:Eu2+ phosphors co-doped with La or Y were synthesized by conventional solid-state reaction technique in reductive atmosphere (a mixture of 5% H2 and 95% N2). The results showed that the co-doping of La and Y could greatly enhance the fluorescence intensity of Ba2SiO4:Eu2+ phosphors. The optimum doping concentration expressed by the x value in (Ba0.985-1.5xREx)2SiO4: 0.03Eu2+ (RE=La or Y) was determined to be of 0.05. The excitation and emission peaks of all as-synthesized phosphors were wide bands. The excitation bands ranged from 250 to 400 nm, which matched well with the wavelength of near ultraviolet white light-emitting diodes (LED) chip and could be used as a potential candidate for the fabrication of white LED. The emission bands from 450 to 550 nm were typical 5d-4f transition emission of Eu2+ and displayed un-symmetry profiles because of the two substitution sites of Ba2+ with Eu2+.