纳米Fe3O4磁流体的制备及其影响因素研究

通过液相共沉淀法制备了Fe3O4水基磁流体,选择油酸作为表面活性剂,获得油酸包覆的Fe3O4纳米粉,将其分散于有机溶剂中,制备了纳米Fe3O4有机基磁流体。采用X-Ray衍射分析仪和粒径分布仪分析了生成物的结构和粒径分布;用FT-IR和高分辨透射电镜表征了生成物的成分和形貌。结果表明:制得的立方晶体纳米Fe3O4平均粒径为16.3 nm,FT-IR图谱中1 593、1 736和2 926 cm-1等处的吸收峰很强烈,这充分说明该纳米粒子被油酸很好地包覆;选择油酸作为表面活性剂,起到表面改性和萃取出纳米粒子的作用;制得的油酸包覆纳米Fe3O4粒子能够稳定分散于有机溶剂中。     

超声诱导银纳米粒子的电化学制备及其表征

在络合剂EDTA、保护剂PVP存在的条件下,通过超声电沉积方法在硝酸银溶液中制备出形状不同的零维、一维银纳米材料。研究结果表明：当硝酸银浓度为0．0118mol／L、硝酸银与EDTA数量比为1：1时,银纳米粒子为类球形,直径约30nm。当加入2g／L的PVP时,可获得直径约30nm,长度不等的银纳米线。选区电子衍射和紫外可见吸收光谱表明,银纳米颗粒具有面心立方结构,其形貌和粒径影响微粒的光吸收特性。     

含纳米碳酸钙、稀土粒子润滑油的摩擦学性能

采用透射电子显微镜（TEM）观察、测定了纳米碳酸钙、稀土（RE）粒子形貌和粒径；制备了含不同浓度与比例的纳米碳酸钙、稀土复合粒子的润滑油，并在四球摩擦磨损试验机上考察了其摩擦学性能；采用扫描电子显微镜与X射线光电子能谱仪分析了磨损钢球表面的形貌、化学组成。研究结果表明，纳米碳酸钙、稀土粒子的最佳的添加量为0.6%，最佳配比为w（CaC03）：w（RE）=1：1；该润滑油具有优良的抗磨、减摩性能；其抗磨、减摩机理与纳米粒子存在形态以及摩擦化学作用有关。     

高温液相醇解法制备钴纳米粒子

利用1,10-癸二醇做还原剂,在油酸和乙二醇辛基苯基醚两种表面活性剂存在下制备出磁性钴纳米粒子,利用XRD、XPS、TEM和激光光散射仪对所制备的钴纳米粒子进行了表征。结果表明：该方法制备的钴纳米粒子具有hcp相,平均粒径大约为30nm。     

纳米Fe3O4粒子粒径对其作润滑油添加剂摩擦学性能的影响

采用化学共沉淀法和沉淀氧化法分别制备了粒径为10 nm和45 nm的球形Fe3O4粒子,研究了粒径对纳米Fe3O4粒子作润滑油添加剂摩擦学性能的影响。结果表明,纳米Fe3O4粒子的粒径对其作润滑油添加剂的减摩抗磨作用有明显影响。粒径为10 nm和45 nm的Fe3O4粒子作润滑油添加剂均具有较好的减摩抗磨作用,但是,粒径为10 nm的Fe3O4粒子的减摩抗磨效果优于粒径为45 nm的Fe3O4粒子的减摩抗磨效果。     

纳米润滑剂的制备及特性研究

探讨了运用纳米润滑剂实现机械零件自修复的理论和途径，研究了纳米润滑剂的制备方法：利用流化床气磨法制备超细铜粒子原料，送入分级机进行一次分级，将超细铜粒子进行相转移处理，并以不同粘度的润滑油进行二次分级处理，可获取含不同粒径的铜纳米润滑剂，并研究了纳米润滑剂的特殊摩擦学性能以及不同粒径的纳米粒子对摩擦学性能的影响，结果表明：用流化床气磨法制备出超细铜粒子原料并进行相转移处理，可获取含不同粒径的铜纳米润滑剂，纳米粒子大部分为4～50nm的颗粒闭，少量呈绒球状，少量占片状，本法制备的纳米润滑剂其铜粒子粒径满足纳米尺寸要求；4种纳米润滑油的摩擦系数分别比基础油的降低1.28倍、2.18倍，3.46倍和4.61倍，在特定的摩擦学系统条件下，纳米粒子粒径有一较佳的尺寸范围，在该范围内，其润滑效果极明显，有着普通润滑剂所不具备的优异性能，在该范围以外，则效果不甚明显。     

油酸修饰纳米镍粒子对润滑油摩擦学性能的影响

采用化学法制备纳米镍粒子,用油酸对其进行表面改性,利用XRD和SEM对其进行表征。将不同质量分数的纳米镍粒子加入F4008船用系统油中,在摩擦磨损试验机上研究其减摩抗磨性能。结果表明,所制备的纳米镍粒子为面心立方结构,其平均粒径分别为40nm,在润滑油中具有良好的分散性能;纳米镍粒子在较高载荷下减摩抗磨效果明显,具有较好的填充修复犁沟的作用。     

W/O微乳液法制备表面修饰纳米氟化镧润滑油添加剂

采用聚异丁烯丁二酰亚胺T152/S-80复合表面活性剂(w(Span80)∶w(Tween20)=2∶3(质量比))/异丁醇/500SN基础油/氟化铵水溶液W/O微乳液体系构建微反应器,通过原位表面修饰制备了含纳米LaF3粒子的液体润滑油添加剂,同时,采用洗涤法制备了干粉纳米LaF3。采用X-射线衍射仪(XRD)和透射电镜(TEM)分析了纳米LaF3粒子的结构和形貌。分别将液体添加剂和干粉加入基础油中,采用离心沉降法考察了不同后续分离方法得到的纳米粒子在基础油中的分散稳定性,用四球机考察了它们的摩擦学性能,最后采用扫描电子显微镜(SEM)观察了磨斑表面形貌。结果表明:所构建的微反应器制备的颗粒状纳米LaF3平均粒径在10~15 nm之间;纳米粒子在基础油中的分散稳定性对其摩擦学性能影响很大,液体添加剂中的纳米粒子在基础油中的分散稳定性和摩擦学性能大大高于干粉粒子;液体添加剂中的表面活性剂不仅有利于纳米粒子在基础油中的稳定分散而且有减摩作用。     

修饰ZnS纳米粒子的减摩抗磨性能研究

利用SRV摩擦磨损试验机考察了粒径约为4nm的二烷基二硫代磷酸（DDP）修饰ZnS纳米粒子作为润滑油添加剂的磨擦学性能，并采用XPS对其摩擦表面进行了研究。结果表明：添加修饰ZnS纳米粒子在摩擦过程中会发生摩擦化学反应，形成一层边界润滑膜，该膜可有效提高十四烷的减摩抗磨和承载能力。     

Fe3O4纳米粒子添加量对润滑油润滑特性的影响

主要研究了润滑油中纳米粒子添加剂的含量对冷挤压过程中润滑特性的影响规律。采用粒径为20～30nm的Fe3O4纳米粒子分散于52#汽缸油中配置成具有不同质量分数的纳米粒子改性润滑油,并将该润滑油应用于钛合金（TA2）棒材的冷挤压实验,论文系统研究了润滑油中Fe3O4纳米粒子的添加量对钛合全冷挤压成形的最大成形力、成形功、表面质量（Ra）及HV的影响规律并对其润滑机理进行了分析,结果表明：当润滑油中Fe3O4纳米粒子质量分数为8％时。纳米改性润滑油的润滑效果最佳,挤压成形力和成形功最小,成形件表面质量最好。纳米粒子的填充与滚动作用及其对52#汽缸油膜的支承作用是改善润滑油润滑性能的主要原因。     

激光刻蚀金银合金胶体的制备及其SERS应用

金属胶体是一种新兴的表面增强拉曼散射(SERS)活性衬底,利用激光液相刻蚀技术制备了金银合金胶体,并通过透射电镜、吸收光谱、表面增强拉曼散射光谱等手段对其特性进行表征。结果表明,合金粒子多数为球形颗粒,颗粒大小在5nm左右,并且有很好的分散性,等离子体共振吸收峰位于428nm。此外,该胶体表现出很好的表面增强拉曼散射活性,且性能稳定可在室温下长时间保存。     

Spectroscopic Studies of the Interaction of Silver Nanoparticles with Methylene Blue

The interaction between silver nanoparticles and Methylene Blue(MB)is studied by UV-Vis spectroscopy and fluorescence spectrometry.The UN-Vis absorption of the silver nanoparticles dramatically with the addition of MB.However,no obvious changes of absorption spectra of MB are observed when silver colloids ate added into the MB solution.In the presence of surfactant SDS,the catalysis of the silver nanoparticles in the reducton of MB by sodium borohydride is exhibited by UV-Vis and fluorescence spectroscopy of MB displaying faster response compared with the absence of the silver nanoparticles.The results show that the activity of surfactant SDS modified silver nanoparticles is great and a strong physical adsorption to MB exists.     

Electron Beam Induced Growth of Silver Nanoparticles

An electron beam inducing method for sprouting large quantities of silver nanoparticles on the surface of silver chloride particles is reported. The electron beam driven process was characterized by time‐dependent scanning electron microscope (SEM) and energy dispersive spectrum (EDS), allowing for observing several key intermediates in and characteristics of the growth process. Theoretical calculation coupled with experimental observation demonstrated that the growth of silver nanoparticles was mostly related to the current density of electron beam. Decomposition of the silver chloride on the surface of sample was under electron beam irradiation resulted in silver nanoparticles and chlorine. This phenomenon could be useful in developing a novel mechanism for preparation of nanostructures and proposing a reference to avoid image distortion during the characterization of silver compounds under SEM. SCANNING 35: 69‐74, 2013. © 2012 Wiley Periodicals, Inc.     

Tribological Performance of Silver Nanoparticle–Enhanced Polyethylene Glycol Lubricants

This article introduces a new type of nanoparticle additive for tribological purposes. A nanolubricant was synthesized and studied that consists of metallic silver nanoparticles suspended in polyethylene glycol (PEG). Silver nanoparticles were prepared directly in liquid PEG by introducing aqueous silver nitrate and subsequent reduction by PEG. The nanolubricant exhibits excellent stability due to poly(vinyl pyrollidone) used as the coating agent. Thorough tribological analysis was performed on the nanolubricant, including rheology, friction, wear, and Stribeck curve analysis. Results show that the nanoparticle additives are capable of reducing both friction and wear at low concentrations. Stribeck curve analysis also revealed that the particles are effective in reducing friction in both the boundary and mixed lubrication regimes. The possible friction and wear reduction mechanism of silver nanoparticles is also discussed in the current work.     

表面修饰氟化镧纳米粒子的制备及摩擦学性能研究

采用化学沉淀法以氟化物(NaF)和稀土氯化盐(LaCl3)为原料制备LaF3纳米粒子;采用透射显微镜(TEM)和X射线衍射仪(XRD)对纳米粒子的结构和形貌进行表征及分析;用硅烷偶联剂KH550对其表面改性,在高速高温摩擦磨损试验机上研究改性后的LaF3纳米粒子添加到纯基础油中的摩擦学性能,分析其抗磨减摩机制。结果表明,LaF3纳米粒子添加到润滑油中能提高其摩擦学性能,起到减摩耐磨效果;摩擦过程中LaF3纳米粒子渗透到试件中,起到修复作用。     

修饰剂对PbO纳米粒子摩擦学性能的影响

用化学方法分别合成了表面为二-十六烷基二硫代磷酸（DDP）单分子层修饰的PbO纳米粒子和油酸（OA）单分子层修饰的PbO纳米粒子,用透射电子显微镜（TEM）表征了它们的形貌,并用四球摩擦磨损试验机比较了它们作为润滑油添加剂的摩擦学行为.结果表明,两种PbO纳米粒子的平均粒径都约为5 nm,且都能起到良好的抗磨效果,由于修饰剂的影响,油酸修饰PbO纳米粒子作为润滑油添加剂能够明显降低摩擦因数,而DDP修饰PbO纳米粒子却不能降低基础油的摩擦因数.     

Fungal mediated synthesis of silver nanoparticles and evaluation of antibacterial activity

Nanoparticles as biomedicine has made a crucial role in health biotechnology. Different transition metals in various forms playing role in nanotechnological advances and biological applications. Silver as one of the nontoxic, safe inorganic antibacterial agents and can serve as replacement of antibiotics. Present research is based on biogenic synthesis of silver nanoparticles (Ag‐NPs) as potential antibiotics from fungal metabolites of Penicillium oxalicum. We used different analytical techniques X‐ray diffraction (XRD) and scanning electron microscopy (SEM) for characterization of biosynthesized silver nanoparticles. Furthermore, the antibacterial activity of biosynthesized silver nanoparticles was checked against Staphylococcus aureus, S. dysenteriae, and Salmonella typhi by using well diffusion method and UV visible spectrophotometer. Maximum zone of inhibition recorded against S. aureus, Shigella dysenteriae was 17.5 ± 0.5 mm (mm) for both species and 18.3 ± 0.60 mm for Salmonella typhi. The biosynthesized silver nanoparticles of P. oxalicum showed excellent antibacterial activity. It was concluded from our results that biosynthesized silver nanoparticles have significant potential and might be useful for a wide range of biological applications such as bactericidal agent against resistant bacteria, preventing infections, healing wounds, and anti‐inflammation.     

MoS2的表面修饰与摩擦学性能研究

分别用油酸（OA）、司班-60（Span-60）、十六烷基三甲基溴化铵（CTAB）-二烷基二硫代磷酸吡啶盐（Py-DDP）对MoS2纳米微粒进行表面修饰，考察了修饰后微粒的形貌、在液体石蜡中的分散稳定性和润滑性能，并采用四球摩擦磨损机测试了其摩擦学性能。结果表明，选用不同修饰剂所得到的修饰MoS2纳米微粒的稳定性和摩擦学性能均有不同程度的提高，其中以CTAB—PyDDP修饰MoS2纳米微粒的分散稳定性更佳，摩擦学性能最好。     

Tribological behavior of ZnS-filled polyelectrolyte multilayers

The pristine polyelectrolyte multilayers (PEMs) were prepared by layer-by-layer deposition technique. The ZnS nanoparticles were in situ-synthesized in the pristine PEMs, and the composite was denoted as ZnS-filled PEMs. The friction and wear properties of ZnS-filled PEMs were investigated on a UMT-2 against stainless steel ball. The morphologies of the wear traces were observed by scanning electron microscope. It was found that ZnS-filled PEMs exhibit higher antiwear life than unfilled ones. This should be attributed to the ZnS nanoparticles formed in the PEMs enhancing the load-carrying capacity. Moreover, the PEMs with three reaction cycles have considerably lower friction coefficient and higher antiwear life than the PEMs with six reaction cycles, that is to say, an optimum amount of ZnS nanoparticles within PEMs can improve the tribological performance greatly.