类球形氧化铈的制备及抛光性能

采用溶剂热法合成了粒径为200 nm左右的类球形Ce O2前驱体,在一定温度下煅烧得到抛光粉,采用X射线衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)、电子衍射、激光粒度分析仪等对其进行了表征和观察;同时考察了溶剂热温度、分散剂种类和用量等因素对合成类球形Ce O2前驱体的影响,以及不同煅烧温度和煅烧时间对单晶硅片抛光性能的影响。结果表明:以氯化铈为铈源,以0.75 mol·L-1NH3·H2O为沉淀剂,乙二醇为溶剂,聚乙烯吡咯烷酮(PVP)为分散剂,搅拌30 min后得到浑浊液转移至50 ml内衬聚四氟乙烯(PTFE)反应罐中,在烘箱中于180℃反应24 h,沉淀分别用去离子水,无水乙醇各洗3次,放于60℃烘箱中烘干,得到氧化铈前驱体,经500℃煅烧2 h为D50=203 nm的类球形Ce O2粉体,粉体分散性好,配成质量分数为0.2%的抛光浆料对n(111)型单晶硅片抛光,得到较高抛光速率和超平整的抛光表面。     

以ZrOCl2为添加剂煅烧ZnS合成ZnO绿色荧光粉

研究以氯氧化锆为添加剂的硫化锌热氧化法合成ZnO绿色荧光粉的过程。XRD衍射图谱表明合成荧光粉的主晶相为六方纤锌矿ZnO，并有少量残存的ZnS相存在。荧光发射光谱在350nm或374nm光激发下只呈现出在510nm左右的绿色峰，氯氧化锆添加可大大提高产物的荧光发射强度，而氧化锆则不能。荧光粉中硫和氯的含量与荧光强度随煅烧温度的关系类似，说明氯离子对合成ZnO的绿色发射有直接贡献。该荧光粉的激发波长与近紫外LED的光输出波长相匹配，可用于白光LED荧光的转换材料。     

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。     

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。     

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)。     

LiZnPO4：Tb^3＋,Ce^3＋ green phosphors with high efficiency

Tb3+ and Ce3+ co-activated LiZnPO4 phosphors with high luminescence efficiency were synthesized by a high temperature solid-state reaction at 1000 oC for 3 h. The XRD patterns, photoluminescence spectra and SEM were recorded and the effects of Tb3+ and Ce3+ concentration, sintering condition on the luminescent properties of as-synthesized phosphors were investigated. The emission spectra under ultraviolet (200-300 nm) radiation showed a dominant peak at 543 nm attributed to the 5D4→7F5 transition of Tb3+, which was greatly en-hanced by the co-doping of Ce3+, indicating that there occurred an efficient non-radiative energy transfer from Ce3+ to Tb3+. The optimal dop-ing concentrations of Tb3+ and Ce3+ were determined to be 9% and 10%, respectively.     

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+.     

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.