共查询到17条相似文献,搜索用时 125 毫秒
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CePO4纳米微粒的帛备及表征 总被引:4,自引:0,他引:4
在醇-水溶剂中用共沉淀表面修饰法制备了烷基磷酸酯修饰的CePO4纳米微粒,初步探讨了表面纳米微粒的制备条件,采用多种分析手段表征了表面修饰CePO4纳米微粒的结构和润滑性能。结果表明,形成了以CePO4为纳米核,有机磷化合物为表面修饰层的CePO4纳米微粒,在有机溶剂中具有良好的分散性,显示出良好的减摩、抗磨和承载性能。 相似文献
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环烷酸铅和烷基水杨酸铅的微波原位合成及其摩擦学性能 总被引:3,自引:0,他引:3
在液体石蜡中采用微波技术原位合成了油溶性环烷酸铅(LN)和十二烷基水杨酸铅(LAS),在高速低负荷(r=1500±10rpm,P=196-392N)和低速高负荷(r=300±10rpm,P=800N)两种条件下,用四球摩擦磨损试验对LN,LAS和对应的羧酸进行了摩擦学性能评价,用往复式摩试验机考察了LN和LAS抗磨减摩性能,结果表明:LN具有良好的抗磨减磨性能和中等的极压性能,且各项摩擦学性能指标均好于LAS。为弄清其作用机理,从分子结构分析了产生摩擦学性能差异的原因,并用SEM及XPS研究了磨斑表面,结果发现:摩擦过程中,LN和LAS都能在摩擦副表面形成吸附膜且部分吸附膜发生摩擦化学反应产生了铅氧化物转化膜,但所形成的吸附膜和转化膜厚度不同。 相似文献
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用MS、FT IR等方法对合成的三正丁基一硫代及四硫代磷酸酯进行了结构表征 ,并在四球摩擦磨损试验机上考察了其在液体石蜡中的摩擦学性能 ;用扫描电镜 (SEM )和X射线光电子能谱 (XPS)对钢球磨痕表面做了分析 .结果表明 :对于钢 钢摩擦副 ,合成的两种硫代磷酸酯可以显著提高液体石蜡的极压抗磨性能 ,但不能改善其减摩性能 .钢球磨损表面XPS和SEM分析结果表明 ,添加剂分子在金属表面发生物理或化学吸附 ,并导致金属表面的腐蚀和摩擦化学反应 相似文献
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核壳结构CdS/ZnS纳米微粒的制备与光学特性 总被引:6,自引:0,他引:6
用微乳液法制备CdS纳米微粒 ,以ZnS对其进行表面修饰 ,得到具有核壳结构的CdS/ZnS纳米微粒 .采用X射线衍射 (XRD)、透射电镜 (TEM )表征其结构、粒度和形貌 ,紫外 可见吸收光谱 (UV)、光致发光光谱(PL)表征其光学特性 .制得的CdS近似呈球形 ,直径为 3.3nm ;以XRD和UV证实了CdS/ZnS核壳结构的实现 .研究了不同ZnS壳层厚度对CdS纳米微粒光学性能的影响 ,UV谱表明随着壳层厚度的增加纳米微粒的吸收带边有轻微的红移 ,同时短波吸收增强 ;PL谱表明壳层ZnS的包覆可减少CdS纳米微粒的表面缺陷 ,带边直接复合发光的几率增大 ,具有合适的壳层厚度时发光效率大大提高 . 相似文献
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In this paper, we describe a surfactant-assisted solution dispersion method to obtain metal nanoparticles, which involves dispersing and stabilizing metal droplets in an appropriate solvent. This method has been successfully used to prepare Pb nanoparticles from bulk Pb. The X-ray powder diffraction and transmission electron microscopy investigations show the formation of Pb nanoparticles possessing the same crystal structure as bulk metal and an average particle diameter of 40 nm. Thermal analysis indicates that Pb nanoparticles have organic shell, which is in agreement with the excellent oil-solubility. In addition, the tribological properties of Pb nanoparticles as additive in oil are discussed. 相似文献
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A facile way for preparing tin nanoparticles from bulk tin via ultrasound dispersion 总被引:3,自引:0,他引:3
In this paper, we reported a facile and rapid process to prepare tin nanoparticles from bulk tin via ultrasound dispersion. The morphology and structure of synthesized tin nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and thermogravimetric analysis (TGA). The results show that the morphology of tin nanoparticles is spherical and the structure of tin nanoparticles has the same crystal structure as the bulk tin. In addition, the tribological property of tin nanoparticles as additives in oil is evaluated on a four-ball tester and the results show that tin nanoparticles exhibit good performance in wear. 相似文献
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Xi-qing Yan Zhi-kui Yin Fang Ai Jie-li Lv Xiu-zhen Deng Zhi-jun Zhang 《Composite Interfaces》2013,20(5):353-365
We applied the microwave-assisted heating method to prepare the pyridine dialkyldithiophosphate-encapsulated Ni (Ni-DDP) nanoparticles. The surface-encapsulated Ni particles were characterized by Fourier transform infrared spectrometer, thermogravimetric analysis, X-ray diffraction, and transmission electron microscopy. Their tribological behavior in lubricate base oil was investigated on four-ball machines. The results show that uniform Ni-DDP nanoparticles about 12 nm can be obtained using microwave heating device and also they exhibit good tribological behaviors dispersed in liquid paraffin. 相似文献
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Well-dispersed undoped and Mg-doped ZnO nanoparticles with different doping concentrations at various annealing temperatures are synthesized using basic chemical solution method without any capping agent. To understand the effect of Mg doping and heat treatment on the structure and optical response of the prepared nanoparticles, the samples are characterized using X-ray diffraction (XRD), energy-dispersive X-ray (EDX), UV–Vis optical absorption, photoluminescence (PL), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements. The UV–Vis absorbance and PL emission show a blue shift with increasing Mg doping concentration with respect to bulk value. UV–Vis spectroscopy is also used to calculate the band-gap energy of nanoparticles. X-ray diffraction results clearly show that the Mg-doped nanoparticles have hexagonal phase similar to ZnO nanoparticles. TEM image as well as XRD study confirm the estimated average size of the samples to be between 6 and 12 nm. Furthermore, it is seen that there was an increase in the grain size of the particles when the annealing temperature is increased. 相似文献
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Preparation of ZnS nanoparticles by ultrasonic radiation method 总被引:3,自引:0,他引:3
J.F. Xu W. Ji J.Y. Lin S.H. Tang Y.W. Du 《Applied Physics A: Materials Science & Processing》1998,66(6):639-641
2 S solution. ZnS nanoparticles were synthesized under ultrasonic radiation. They were studied by X-ray diffraction (XRD), transmission
electron microscopy (TEM), UV spectrophotometry, and X-rayphotoelectron spectrometry (XPS). XRD revealed that the ZnS nanoparticles
prepared have a zincblende structure. TEM observations showed that the ZnS nanoparticles are in a spherical form with an average
diameter of 40 nm. XPS results proved that, for our sample, the binding energies of Zn 2p and S 2p are the same as those of
bulk single-crystal, but the full widths at half maximum of the XPS peaks are larger than those of bulk single-crystal.
Received: 22 September 1997/Accepted: 5 January 1998 相似文献
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L. Kolodziejczyk D. Martínez-Martínez T. C. Rojas A. Fernández J. C. Sánchez-López 《Journal of nanoparticle research》2007,9(4):639-645
The tribological performance of lubricants is favourably altered by adding small amounts of nanoparticles which provide reduced
wear and low friction. However, one of the main difficulties of using nanoparticles as additives is their dispersion or dissolution
in lubricant oils, typically of hydrocarbon nature. With the surface modification of nanoparticles through long chain high
molecular weight hydrocarbons, stable dispersions in lubricant oils become feasible. Here we show that using surface-modified
Pd nanoparticles (2 nm size) with tetraalkylammonium chains, stable dispersions in lubricant oils become feasible with excellent
tribological properties (friction 0.07, wear resistance 10−10 mm3/Nm). Electrical contact measurements were also used to monitor the conductivity of the contact during sliding. The use of
these nanoparticles made decrease the electrical resistance of the contact a percentage of 97 to 99.5% in comparison with
the initial value measured for the base oil alone. To understand these phenomena the contact surfaces and Pd nanoparticles
were studied after friction by scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDX) and
transmission electron microscopy (TEM), respectively. The outstanding performance is attributed to a combination of factors
as metallic character of palladium, nanometric size, and replenishment of Pd nanoparticles onto the contact forming a transfer
layer. This discovery opens new perspectives of using metallic nanoparticles as lubricant additives for small contacts and
connectors applications. 相似文献