溶胶-凝胶法制备稀土CeO2掺杂纳米钨粉的研究

以偏钨酸铵(AMT)、柠檬酸和硝酸铈为原料,用溶胶-凝胶法(sol-gel)制备稀土CeO2掺杂纳米钨粉。通过热重-差热(TG-DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)、比表面积法(BET)等测试手段对复合粉体的合成工艺、物相、颗粒形貌和粒径进行了分析。结果表明:当pH值为1时,还原后的粉体颗粒呈准球形,无团聚,稀土元素以CeO2形式存在且均匀地分布在钨粉中,平均颗粒粒径为80nm左右,满足制备高性能掺杂稀土氧化物亚微米结构浸渍阴极的要求。     

溶胶-凝胶法制备喷镀钼粉

采用溶胶-凝胶法重点研究了制备球形喷镀粉的湿法过程。试验结果表明：影响球形钼粉几何形状的因素包括无机酸浓度、有机络合剂和高分子表面活性剂种类以及搅拌强度等。胶凝过程的pH范围pH=4—5，即为酸性。     

均匀掺杂稀土钼粉的制备

采用溶胶凝胶(Sol-Gd)和两步氢还原法，成功制备了掺杂复合RE2O3(RE2O3=La2O3 Y2O3)的稀土钼粉末，采用XRD，TEM分析手段对还原后的粉末成分、形貌、粒度等进行分析。结果表明：所制备的粉末中，Mo是以单质形式出现，RE元素以氧化物形式存在，稀土钼粉末粒径在70nm左右。采用放电等离子快速烧结方法(SPS)制备了致密样品，对样品表面和截面的稀土元素分布情况分析表明稀土元素分布非常均匀。     

稀土掺杂钼制品的组织和性能研究

采用液-液掺杂工艺制得稀土掺杂钼粉及钼(合金)坯,通过调整掺杂稀土的种类及含量考察了其对钼粉及钼(合金)坯组织及性能的影响,结果表明,掺杂稀土的种类和掺杂含量的变化对Mo - La -Y复合粉体的形貌及尺寸的影响不明显;钼(合金)坯基体颗粒总体上随掺杂含量的增加而变细,而在相同掺杂含量下,双元掺杂比单元掺杂的细化作用更...     

稀土掺杂钼粉的粒度控制

通过对稀土掺杂钼粉的费氏平均粒度，松比，粒度分布等的测试分析，研究了稀土掺杂剂对钼粉粒度的影响。结果表明：稀土元素的加入抑制了钼粉颗粒的长大，改变还原温度对颗粒长大的效果不理想，面采用K含量高的钼酸铵生产的稀土掺杂钼粉，颗粒较大且其粒度分布较好，其在掺杂棒的实际生产中取得良好效果，给出了提高稀土掺杂钼粉粒度的有效方法。     

超声波-溶胶-凝胶法制备纳米二氧化锡粉末

用超声波－溶胶－凝胶法制得了纳米SnO2粉末，用XRD和TEM等方法对粉末进行表征，并研究了超声场，pH值和洗涤方式对产品粒度与团聚的影响。     

纳米粉体的溶胶-凝胶法制备技术

系统地概述了溶胶-凝胶法制备纳米粉体的技术方法、特点和研究进展,并认为溶胶-凝胶法具有许多优点,是一种极有应用前景的纳米粉体的制备方法。     

溶胶-凝胶法稀土光学材料研究进展

本文介绍了溶胶—凝胶法光学材料的制备方法及其基质特性，对稀土离子及其配合物掺杂于溶胶—凝胶基质进行了评述，并对将来的发展趋势进行了预测。     

溶胶-凝胶自燃合成掺杂纳米二氧化钛的相变

以TiCl₄为前驱体,采用溶胶-凝胶自燃合成的方法制备了同时掺杂Ce³⁺,Fe³⁺,Zn²⁺的纳米TiO₂粉体．用X光衍射法对粉体的相组成进行了表征．用正交试验研究方法考察了Fe/Ce、（Fe+Ce）/Ti、柠檬酸/Ti（物质的量的比）、煅烧温度、煅烧时间等对产物相组成的影响。结果表明,柠檬酸/Ti,煅烧温度,（Fe+Ce）/Ti对产物相组成具有显著影响。     

硬脂酸溶胶凝胶法-共沸蒸馏法制备钙钛矿型纳米LaCoO3

用硬脂酸溶胶凝胶-共沸蒸馏法制备了纳米LaCoO3,用差热-热重、 透射电镜及红外等手段对粉体进行了表征,并对配合物溶胶-共沸蒸馏脱水的干燥机制进行了探讨.实验结果表明:硬脂酸溶胶凝胶法制备纳米粉体时,配合物溶胶的干燥脱水是不可缺少的一步.共沸蒸馏所用的溶剂苯是通过物理吸附作用替代了配合物溶胶中的水,其机理是靠降低粒子间毛细管力来减少聚集作用的,从而防止了干燥及后续煅烧阶段的粉体团聚.     

Preparation and characterization of rare earth fluorescent anti-counterfeiting fiber via sol-gel method

A benzoic acid rare earth (Tb) complex was synthesized and characterized. The excitation and emission spectra of the complex were investigated, and then pure organic complex was incorporated with inorganic matrices (SiO₂) through sol-gel method. The composition and structure of the hybrid complex was characterized through the IR spectra, TG, TEM and fluorescent spectrometer. Furthermore, the polypropylene (PP) fluorescent fiber with the organic-inorganic hybrid was prepared by melt spinning. The fluorescent and mechanical properties of the fiber were also tested. The results showed that after sol-gel coating the average particulate dimension of the hybrid rare earth complex was less than 100 nm and thermal stability was improved. Meanwhile, the fiber possessed excellent fluorescent and mechanical properties, which could be used as a candidate applied to excellent fluorescent anti-counterfeiting fiber.     

Preparation and characterization of rare earth fluorescent anti-counterfeiting fiber via sol-gel method

A benzoic acid rare earth(Tb) complex was synthesized and characterized.The excitation and emission spectra of the complex were investigated,and then pure organic complex was incorporated with inorganic matrices(SiO2) through sol-gel method.The composition and structure of the hybrid complex was characterized through the IR spectra,TG,TEM and fluorescent spectrometer.Furthermore,the polypropylene(PP) fluorescent fiber with the organic-inorganic hybrid was prepared by melt spinning.The fluorescent and mechanical properties of the fiber were also tested.The results showed that after sol-gel coating the average particulate dimension of the hybrid rare earth complex was less than 100 nm and thermal stability was improved.Meanwhile,the fiber possessed excellent fluorescent and mechanical properties,which could be used as a candidate applied to excellent fluorescent anti-counterfeiting fiber.     

Preparation and laser induced damage properties of rare earth doped BAS glass

Rare earth doped B2O3-Al2O3-SiO2 glass （RExBAS, x=5, 10, 20; RE=La, Sm） were prepared by solid state reaction method. Optical transmission spectra of such glass were characterized by ultraviolet spectrometers, and 1064 nm laser induced damage performance was investigated through the method of ＂1-on-1＂. The results indicated that there was a strong absorptive peak near 1064 nm in SmxBAS glass, the peak was enhanced with increasing x. While LaxBAS glass was transparent to 1064 nm laser, at the same time, the results of laser induced damage showed that the anti-laser induced damage performance of such glass was strengthened with the addition of rare earth oxide. Furthermore, the laser induced damage threshold （LIDT） of SmxBAS glass was significantly higher than that of LaxBAS glass. Consequently, Sm^3＋ doping was favor in the improvement of anti-laser induced damage performance for BAS glass.     

溶胶凝胶法制备掺杂纳米TiO2粉末及其光催化性能

采用溶胶–凝胶法制备掺锌纳米TiO2粉末、掺氮纳米TiO2粉末以及锌氮共掺纳米TiO2粉末(掺杂量均为1%)。采用X射线衍射仪(XRD)、场发射扫描电镜(FESEM)、透射电镜(TEM)、傅立叶红外光谱测试仪及紫外可见–分光光度计等分析粉末的物相、形貌、光学性能及光催化性能。结果表明:在纳米TiO2粉末中掺锌或氮,既不会改变粉末的晶体结构,也不会产生新相。与纯TiO2粉末相比,掺锌或掺氮后粉末光催化性能更好。但同时掺入锌和氮,反而会降低TiO2粉末的光催化性。在热处理温度为500℃条件下制备的掺氮TiO2粉末光催化活性最高。     

稀土元素Y对粉末冶金2A12铝合金组织和力学性能的影响

在铝合金粉末中添加质量分数为0、0.2%、0.4%及0.6%的稀土元素Y,利用粉末冶金法制备2A12铝合金。通过金相组织观察、X射线衍射分析、扫描电子显微形貌表征、能谱分析及力学性能测试等手段,研究了稀土元素Y对粉末冶金2A12铝合金组织和性能的影响,总结了Y在铝合金中的分布特征。结果表明,当稀土元素Y的质量分数为0.2%时,2A12铝合金抗拉强度最高,塑性最好;添加Y可以抑制铝合金晶粒在烧结过程中的长大;稀土元素Y主要以YAl相、Cu₂Y相和YAl₂相的形式分布在基体晶界处,少量Y固溶在铝基体中。     

溶胶-凝胶法制备超细Mo-Cu粉末及性能表征

以七钼酸铵和硝酸铜为原料通过溶胶-凝胶法制备Cu含量(质量分数)为20%的超细Mo-Cu复合粉末,再在1050～1200℃下烧结粉末压坯制得Mo-Cu复合材料;通过热重分析(DTA-TG)、X-ray衍射分析(XRD)和透射电镜(TEM)等分别对干凝胶煅烧前后的粉体以及还原后所得Mo-Cu复合粉末进行表征,通过扫描电镜观察Mo-Cu烧结体的显微组织,并对其密度、物理和力学性能进行测定,探索制备高致密、高性能Mo-Cu复合材料新工艺.结果表明:通过溶胶-凝胶法可以制得平均粒度为150nm、组成均匀的Mo-Cu超细粉末,该粉末具有良好的烧结性能,其成形压坯在1200℃下于H2气氛中烧结90 min后,相对密度可达99.78%,烧结体的抗弯强度和维氏硬度分别为988 MPa和HV 227,电导率和导热系数分别为42.56%IACS和157 W/(m·K),室温至450℃的热膨胀系数在6.7×10-6～7.6×10-6K-1之间.     

A hydrometallurgical method of energy saving type for separation of rare earth elements from rare earth polishing powder wastes with middle fraction of ceria

This study described a hydrometallurgical method to investigate the separation of rare earth elements(REEs)from rare earth polishing powder wastes(REPPWs)containing large amounts of rare earth oxides with a major phase of CeO_2 and minor phases of La_2O_3,Pr_2O_3,and Nd_2O_3 using a process devised by the authors.The suggested approach consisted of five processes:the synthesis of NaR E(SO_4)_2·xH_2O from rare earth oxides in Na_2SO_4-H_2SO_4-H_2 O solutions(Process 1),the conversion of NaR E(SO_4)_2·xH_2O into RE(OH)_3 using NaO H(Process 2),and the oxidation of Ce(OH)_3 into Ce(OH)_4 using air with O_2 injection(Process 3),followed by Processes 4 and 5 for separation of REEs by acid leaching using HCl and H_2SO_4,respectively.To confirm the high yield of NaR E(SO_4)_2·xH_2O in Process 1,experiments were carried out under various Na_2SO_4 concentrations(0.4–2.5 mol/L),sulfuric acid concentrations(6–14 mol/L),and reaction temperatures(95–125 oC).In addition,the effect of the pH value on the separation of Ce(OH)_4 in HCl-H_2 O solutions with Ce(OH)_4,La-,Pr-,and Nd(OH)_3 in Process 4 was also investigated.On the basis of above results,the possibility of effective separation of REEs from REPPWs could be confirmed.     

电感耦合等离子体质谱法测定砂金中稀土元素

建立了砂金中15种稀土元素的电感耦合等离子体质谱测定方法。考察了基体Au的谱线干扰及基体效应,采用In内标补偿基体对待测信号的抑制作用。仪器检测限为0.000 9～0.002 9μg/L,加入标准物质的回收率为98%～106.7%,分析结果的相对标准偏差（RSD）为0.33%～1.79%。该方法简单、快速、灵敏、准确。