X射线衍射技术在材料分析中的应用

X射线衍射分析技术是一种十分有效的材料分析方法,在众多领域的研究和生产中被广泛应用。介绍了X射线衍射的基本原理,从物相鉴定、点阵参数测定、微观应力测定等几方面概述了X射线衍射技术在材料分析中的应用进展。     

半导体量子点材料在Nd:YAG激光辐照下的非线性光学效应

使用10 n,脉冲调Q Nd:YAG激光器Z-scan技术测量了化学合成的无掺杂硫化锌量子点(QDs)以及掺Mn2+硫化锌量子点(QDs)的非线性光学特性,并使用透射电镜技术(TEM)以及X射线衍射法(XRD)表征合成材料的纳米结构.在室温下,分别利用UV-VIS分光光度计和分光荧光计测量了人工合成QDs胶体溶液的线性...     

几种测量纳米粒子粒径方法的比较研究

以纳米碳酸钙粒子作为测量对象,分别采用x射线衍射法(XRD)、透射电子显微镜法(TEM)及原子力显微镜法(AFM)测量其粒径.结果表明:x射线衍射法测量的纳米粒子粒径可能小于纳米粒子实际平均粒径,透射电子显微镜法和原子力显微镜法测量的纳米粒子粒径可能大于纳米粒子实际平均粒径.分析探讨了3种方法的应用领域、测量范围、优缺点等.     

低温碱热法制备尖晶石型LiMn2O4纳米棒

以硫酸锰和氢氧化锂为原料,采用碱热法在KOH-NaOH体系中成功地合成了尖晶石型LiMn2O4纳米棒。利用X射线衍射(XRD)和扫描电子显微镜(SEM)对样品的结构与形貌进行了表征,结果表明:反应温度、反应时间和氢氧化锂的用量对产物的结构和形貌有较大影响。     

X射线衍射光学部件的制备及其光学性能表征

综述了国内外在纳米加工X射线衍射光学透镜方面的研究现状和最新进展。介绍了作者团队过去三年在这方面做的工作。针对衍射透镜关键技术,研发了具有大高宽比形貌的电子束光刻基础工艺;结合金电镀,提出了纳米尺度波带片的制造技术,并将该工艺成功扩展于分辨率板(Siemens star)和集成光栅型会聚透镜的研制。运用蒙特卡罗模拟和显影动力学,探索了电子束光刻技术所能够实现的最大高宽比以及造成这种限制的物理根源;成功研制了50~100nm的波带片透镜(其中,100nm波带片高宽比为16∶1)、50~300nm的分辨率测试板(其中,300nm测试板高宽比为10∶1)和200nm的会聚透镜(高宽比为10∶1)。对所研制的光学部件在同步辐射光源进行了实验表征。结果表明,100nm波带片聚焦斑尺寸为234nm,测试板和会聚透镜的光学特性与国外同样光学部件到达同等水平;会聚透镜辐照的均匀性为99%。最后,总结了近几年我国X射线衍射透镜的发展进度,指出了衍射光学部件光学性能发展的最大瓶颈是分辨率与衍射效率相互制约,提出了提高光学部件衍射效率的具体途径,给出了我国X射线衍射透镜技术的未来发展路线图。     

粉末衍射分析在石油化工领域中的应用

简要介绍了X射线衍射分析在石油化工领域中的应用，包括未知物物相鉴定，催化研究和聚合物结构参数测定等。     

EDXRD安检系统衍射谱数据库的仿真研究

能量色散X射线衍射(EDXRD)系统在安检领域具有重要的应用前景。基于能量色散X射线衍射原理,以ICDD-JCPDS数据作为初始能谱信息,分析了X射线光源、系统结构、探测器分辨率及物质衰减效应对衍射能谱的影响,建立了与系统特性相对应的衍射谱仿真模型。利用该模型,仿真了不同结构参数EDXRD系统的衍射谱,仿真谱和实际测量结果吻合。在此基础上,仿真了海洛因和NH_4NO_3在不同晶体结构下的衍射能谱,为EDXRD安检系统的识别数据库提供了一种有效的构建方法。     

云母矿粉中游离二氧化硅含量的快速测定

以具有复杂晶体结构、X射线衍射峰与游离二氧化硅衍射峰严重重叠及易择优取向等特点的云母矿粉为研究对象,探讨了利用具有超能探测器的X射线衍射仪在连续扫描模式下收谱以及Rietveld全谱拟合快速测定其中游离二氧化硅含量的可行性。结果表明:与步骤复杂、测试周期长等的传统X射线衍射标准曲线法相比较而言,该方法不仅操作简便、收谱快速而且结果准确性高、重现性好。重现性测定的最大标准偏差为1.39%。实际样品测试也表明此方法是一种简便易行的测定各类粉尘中游离二氧化硅含量的好方法。     

X射线多重衍射效应

本文介绍了X射线多重衍射效应的起因,多重衍射图谱的指标化,给出了用普通X射线粉末衍射仪观测多重衍射效应的方法,并简要说明了多重衍射效应的应用。     

软X射线傅里叶变换光谱仪原理及结构特性研究

软X射线傅里叶变换光谱仪是傅里叶变换光谱学最前沿的研究领域。本文采用夫琅和费衍射理论分析了新型Mach—Zehnder分波前式软X射线傅里叶变换光谱仪的工作原理,探讨了探测器接收狭缝宽度的确立条件,得出光程差反演公式,指出谱仪研制的关键环节及难点。     

纳米ZnS粒子作为润滑油添加剂摩擦学性能研究

采用均匀沉淀法制备了硬脂酸修饰的纳米ZnS粒子,用四球摩擦磨损试验机考察了其作为润滑油添加剂的摩擦学性能,并用扫描电子显微镜和X射线光电子能谱仪对磨斑进行了表面分析.结果表明:在一定添加量范围内,硬脂酸修饰的纳米ZnS粒子可明显改善基础油的摩擦学性能;在摩擦过程中,纳米ZnS粒子在摩擦表面的沉积和通过摩擦化学反应生成的化学反应膜,显著提高了基础油的抗磨减摩性能.     

Preparation and tribological properties of surface‐modified ZnS nanoparticles

Surface‐modified ZnS nanoparticles have been fabricated, and the morphologies and crystalline structures of the powder have been characterised by transmission electron microscopy, X‐ray diffraction and Fourier transformation infrared spectrum. The tribological properties of the surface‐modified ZnS (SM‐ZnS) nanoparticles as an additive in PEG400 were evaluated with a four‐ball tester. It was found that the as‐prepared SM‐ZnS nanoparticles had a very narrow size distribution, with the average diameter about 5–10 nm. The SM‐ZnS nanoparticles as the additive led to an obvious improvement in the anti‐wear and friction‐reduction properties of the synthetic PEG400. Analysis indicated that a boundary film was formed during the friction process. Copyright © 2014 John Wiley & Sons, Ltd.     

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.     

冷轧连续退火炉炉辊涂层失效分析

利用扫描电镜、能谱仪、X射线衍射仪等对某公司冷轧连续退火炉炉辊涂层失效的原因进行了分析.结果表明:炉辊涂层失效的主要原因是硫、锌、钠元素在涂层表面富集,导致在其表面生长出主要由ZnS相组成的"隆起物",随着"隆起物"的不断生长和剥落,使涂层质量受到严重影响,从而发生失效;同时,涂层与基体的结合界面处也发生了一定程度的内氧化,加速了涂层的失效.     

A grid-type semitransparent X-ray monochromator

A grid-type semitransparent X-ray monochromator is described. It can be used for splitting polychromatic beams, mixing beams of different spectral compositions, and radiation intensity monitoring. The monochromator is manufactured from a Si single crystal and contains a set of periodically spaced slit openings oriented in parallel to the diffraction plane. The data of reflectivity and transparency measurements obtained by scanning the diaphragm perpendicular to the measurement plane are presented and compared with the results of computer simulation.     

纳米二氧化铈润滑油添加剂的摩擦学特性

用适当的表面活性剂对纳米二氧化铈粒子进行表面改性处理,采用透射电镜(TEM)和X-射线衍射法(XRD)观察与测量纳米二氧化铈粒子的形貌、结构和平均直径。将改性后的纳米二氧化铈粒子作为润滑油添加剂,采用四球摩擦磨损试验机测定添加纳米二氧化铈粒子的润滑油的摩擦学性能。利用扫描电镜(SEM)观察磨斑表面形貌以及纳米二氧化铈粒子在摩擦表面的形态等,并探讨了纳米二氧化铈粒子具有优良摩擦学性能的机制。结果表明,经表面改性的纳米二氧化铈在润滑油中具有良好的分散、稳定性;纳米二氧化铈粒子的添加量为0.6%(质量分数)左右时,润滑油在室温与较高温度下均具有优良的减摩、抗磨作用。     

修饰剂对ZnS纳米粒子摩擦学性能的影响研究

合成了粒径约为3nm的二-十六烷基二硫代磷酸（DDP）修饰ZnS纳米粒子和油酸（OA）修饰ZnS纳米粒子,并分别用四球摩擦磨损试验机考察了它们作为润滑油添加剂的摩擦学行为。结果表明,二者都能起到良好的抗磨效果,油酸修饰ZnS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ZnS纳米粒子反而使摩擦因数略有升高。     

The Preparation and Tribological Investigation of Ni–P Amorphous Alloy Nanoparticles

Amorphous Ni–P alloy nanoparticles were synthesized by chemical reduction of nickel acetate in water reacted with sodium hypophosphite under stirring. The nanoparticles were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Results of XRD and TEM showed that nanoparticles have an average diameter 100 nm. And XPS analysis indicated that part of the surface of Ni–P amorphous alloy nanoparticles was oxidized. The tribological properties of the prepared Ni–P nanoparticles as an additive in lithium grease were evaluated with a four-ball friction and wear tester. The worn surfaces of the lubricated GCr15 steel were analyzed by means of XPS and scanning electron microscopy (SEM). The lubricating mechanisms were discussed on the basis of XPS and SEM analyses of the worn steel surfaces. The results show that these nanoparticles as a grease additive can effectively enhance the friction-reduction and antiwear ability of lithium grease. Tribochemical reactions were involved for steel–steel frictional pair lubricated with the lithium grease containing amorphous Ni–P alloy nanoparticles, with the formation of a boundary lubricating and protecting film composed of additives of lithium grease and tribochemical reaction products (iron phosphate, iron oxides, nickel oxide, nickel, etc.) of the lubricants. This contributes to improve the tribological properties of the lithium grease.     

复合电铸Ni-La2O3纳米复合材料的组织结构和性能

采用复合电铸工艺制备了不同La2O3纳米颗粒含量的Ni—La2O3纳米复合材料，用扫描电子显微镜和X射线衍射仪观察分析了纳米复合材料的表面形貌及组织结构，与电沉积纯镍作对比研究了纳米复合材料的显微硬度和耐磨损性能。结果表明，由于La2O3纳米颗粒的存在，导致Ni-La2O3纳米复合材料的组织结构发生了改变，它比纯镍沉积层具有更高的显微硬度及耐磨性，且La2O3纳米颗粒质量分数越大，纳米复合材料的显微硬度越高，耐磨性越好。     

光合成普鲁士蓝/聚苯乙烯微球核壳复合材料及其电催化研究

采用一步光照法合成普鲁士蓝/聚苯乙烯微球核壳结构复合材料.利用聚氯化二烷基二甲基铵阳离子吸附到聚苯乙烯微球表面,采用光沉积的方法在其表面合成一层普鲁士蓝外壳.聚电解质和光照时间对该复合材料的合成有着重要的影响.采用扫描电子显微镜、X-射线衍射和X-射线光电子能谱,对该复合材料的结构和形貌进行了分析.该复合材料对H2O2显示出良好的电催化性能,利用该复合材料制备的H2 O2传感器对H2O2的检测具有较宽的线性检测范围、高的灵敏度和稳定性.在5×10-6～3.6×10-3 mol·L-1范围内对过氧化氢的灵敏度为2.6×10-2 A·cm-2·M-1,在4.5× 10-3～1×10-2 M范围内对过氧化氢的灵敏度为8.5×10-3 A·cm-2· M-1.