纳米复合镀技术的研究现状

纳米复合镀技术是建立在传统复合镀基础上的一种新工艺．综述了纳米颗粒与金属离子的共沉积机理、纳米复合镀工艺以及纳米复合镀层的研究现状，并为今后的研究提出了建议。     

Influence of nanometric CeO2 coating on high temperature oxidation of Cr

Isothermal and cyclic oxidation behavior of chromium and its superficially applied nanometric CeO₂ samples were studied at 900℃ in air. Scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and high resolution electronic microscopy (HREM) were used to examine the morphology and micro-structure of oxide films. It was found that ceria addition greatly improved the anti-oxidation ability of Cr both in isothermal and cyclic oxidizing experiments. Acoustic emission (AE) technique was used in situ to monitor the cracking and spalling of oxide films, and AE signals were analyzed in time-domain and number-domain according to the related oxide fracture model. Laser Raman spectrometer was also used to study the stress status of oxide films formed on Cr with and without ceria. The main reason for the improvement in anti-oxidation of chromium was that ceria greatly reduced the growing speed and grain size of Cr₂O₃. This fine-grained Cr₂O₃ oxide film might have better high temperature plasticity and could relieve parts of compressive stress by means of creeping, and maintained the ridge character and relatively low internal stress level. Meanwhile, ceria application reduced the size and the number of interfacial defects, while remarkably enhanced the adhesive property of Cr₂O₃ oxide scale formed on Cr substrate.     

ZrO2-SiO2纳米复合微粒的制备与性能

以水玻璃为原料制备了3种不同粒径的纳米二氧化硅水分散液,滴加入锆酸四正丁酯异丙醇溶液,使水解的锆酸定向吸附至二氧化硅表面并缩聚为氧化锆从而形成氧化锆包覆的二氧化硅水溶胶。透射电子显微镜、电子能谱分析和不同微粒表面ζ电位与Gouy-Chapman模型计算表明:二氧化硅表面氧化锆的包覆率为57%。紫外可见光研究表明:该纳米微粒紫外吸收随粒径的增大有所下降,可见光的透过性也略有下降。经喷雾干燥成粉后,复合微粉的比表面积为135m2/g。XRD分析表明:有少量的ZrO2单斜晶型存在,600℃煅烧后,粉体比表面积100.5 m2/g,呈单斜晶型;1 300℃煅烧后,粉体比表面积为67.3 m2/g,为四方晶型结构。     

反相乳液聚合制备阿霉素磁性抗癌毫微粒

以阿霉素为模型药物,Fe3O4为磁核,乙烯吡咯烷酮(NVP)为载体,通过反相乳液聚合法制备了阿霉素磁性抗癌毫微粒,并对影响阿霉素磁性毫微粒大小及粒径分布的因素进行了考察.环境扫描电镜表明,最佳制备条件下制得的毫微粒外观光滑,大小均匀;激光光散射测定表明该产物平均粒径为500 nm,粒径分布系数0.23,呈单分散分布;红外光谱测试证明本实验所制备的毫微粒是由阿霉素、Fe3O4和聚乙烯吡咯烷酮共同组成.     

用黄钠铁矾渣制备复合镍锌铁氧体

对黄钠铁矾渣制备复合镍锌铁氧体进行研究。研究结果表明：当黄钠铁矾渣与无烟煤按质量比为5：1均匀混合，在800℃还原焙烧0．5h，焙烧渣用0．5mol／L硫酸溶液按液固比7：1在70℃浸出40min时，渣中93％的铁和镍进入浸出液中。浸出液经过净化除杂后得到含镍的硫酸亚铁溶液，加入计量的硫酸镍和硫酸锌，采用共沉淀法，以NH4HCO3为沉淀剂，通过改变沉淀剂的用量控制pH值制备镍锌铁碳酸盐。将镍锌铁碳酸盐在800℃煅烧2h得到具有尖晶石结构的Ni0.5Zn0.5Fe2O4粉体，粒径约为59nm，粒度均匀，呈球形；煅烧4h时粉体粒径变大，粒度不均匀，呈棒状。     

Au-MgF2复合纳米颗粒薄膜有效介质理论的颗粒尺寸效应修正

在研究Au-MgF2复合纳米颗粒薄膜体系的光学行为时,Maxwell-Garnett理论及Bruggeman理论结果与实验结果之间存在一些差异,这些差异主要是由于Maxwell-Garnett理论及Bruggeman理论未考虑复合体系中金属纳米颗粒的尺寸效应。文章在考虑尺寸效应修正的基础上,得出了Maxwell-Garnett及Brugge-man理论结果;这些结果与实验值符合较好。     

Preparation and Kinetics of the Thermal Decomposition of Nanosized CuC_2O_4-ZnC_2O_452H_2O

0 IntroductionMicaxteidon mse tianl onxeiwde ste hcahvneol voegriyesi .m pTohrteayn tc aanpp lbie-used as prospective materials for superior technicalceramics , materials for magnetic recording, manyelectronic components ,sensors ,catalysts as well asthe high-temperature superconductors .CuO/ZnO catalyst was one of the i mportantcatalysts applied for the catalytic generation of hy-drogenfromthe reaction of methanol with oxygeninthe presence of steam[1]. Since nanometer particlepossesses many…     

纳米氧化锌的表面修饰及其摩擦学行为研究

采用直接沉淀法制备了粒径分布均匀（平均大小约为10nm）的纳米氧化锌,并采用X射线衍射（XRD）和透射电子显微（TEM）手段进行了表征.以山梨糖醇酐三油酸酯（span-60）、油酸、月桂酸钠和氟碳（（C—F）x）为表面活性剂对纳米氧化锌进行表面修饰,将修饰过的纳米氧化锌添加到液体石蜡中,使其质量分数为0.5%,进行沉降实验.用傅里叶红外线光谱仪（FT-IR）对表面修饰过的纳米氧化锌进行分析,用Falex-6型四球摩擦磨损实验机进行摩擦磨损实验,用扫描电子显微镜（SEM）对钢球的表面进行形貌分析.结果表明,在液体石蜡中加入修饰过的纳米氧化锌,其摩擦系数及钢球的磨损程度均大大降低,其中经含有羧基的油酸修饰的纳米氧化锌在液体石蜡中的分散性最好,抗磨减摩性能最佳.     

Non-Equlibrium Doping,Phase Selection and Fuctionalization in TiO_2 Nanoparticls Prepared by RF Thermal Plasma Methods

1 Results Control of dispersion in synthesized nano-size powders is crucial to the realization of nanoparticles application,such as the fabrication of functional nano-strucured bodies.Dispersion of plasma-synthesized TiO2 nanoparticles,which are formed in-flight in the high temperature thermal plasma,should be superior to those prepared by ordinal wet processes,as the particles have no surface residual groups.RF thermal plasma is characterized by extremely high temperatures,and rapid heating and cooling...     

不同pH值下制备的CMC/Eu纳米络合粒子的粒径及其分布与粒子荧光性质的关系

使用可生物降解的羧甲基纤维素(CMC)和Eu3+络合反应,在不同的pH值下制备了CMC/Eu纳米络合粒子.FT-IR结果证实CMC链上的羧基、未被取代的羟基中的氧原子及醚键的氧原子均参与了与Eu3+的反应;SEM及TEM结果表明,所合成的CMC/Eu络合物是纳米级的,并呈现较弱的多晶型结构;固态紫外吸收光谱表明,CMC是一个良好的能量供体和荧光敏化剂.产物的粒径及其分布与粒子荧光性质间具有依赖关系.pH=7时,所制备的产物的粒径最小(150~200nm)、分布最均匀,其荧光强度最强,荧光单色性也高;随着pH值的增大,粒子团聚加剧,产物的粒径增大,其荧光强度相应减弱,这一结果体现了量子尺寸效应.