金刚石表面镀钛层的X射线衍射测量

对表面有镀钛层的金刚石晶体进行了射线衍射测量,得到了金刚石晶体表面有金属化合物形成的结果.同时,得到了一个较有疑问的X射线衍射峰,文章尝试进行一些分析.     

X射线物相分析在火炸药鉴定中的应用

1895年发现X射线以后,1912年德国物理学家劳瓦(Laue)等人发现了晶体对X射线的衍射,从而建立了用X射线衍射研究晶体结构的方法。人们通过晶体的衍射现象,认识到晶体中原子(离子或分子)的周期排列,进一步了解物质的本质。由于先进科学技术的应用,X射线衍射法不断的发展,应用面愈来愈广。X射线单晶结构测定和多晶物相分析是研究物质结构的重要手段,尤其是物相分析应用更为广泛和普及。目     

X射线物相分析在火炸药鉴定中的应用

1895年发现X射线以后,1912年德国物理学家劳瓦(Laue)等人发现了晶体对X射线的衍射,从而建立了用X射线衍射研究晶体结构的方法。人们通过晶体的衍射现象,认识到晶体中原子(离子或分子)的周期排列,进一步了解物质的本质。由于先进科学技术的应用,X射线衍射法不断的发展,应用面愈来愈广。X射线单晶结     

谈微晶玻璃残余应力的测量方法

分析了微晶玻璃中残余应力的形成机理及表现特点,并对几种常用测定残余应力的方法进行了比较。提出 了用X射线衍射法和中子衍射方法组合运用并结合其他非破坏性测量方法来测定微晶玻璃残余应力。     

硒化锌晶体光学加工中的宏观应力

采用化学-机械加工工艺加工ZnSe晶体器件.用X射线衍射分析技术测定晶体器件在加工过程中宏观应力的变化.结果表明:加工后器件的损伤层厚度接近为零.抛光后的器件和加工前的器件的宏观应力相近,表明用该工艺加工对器件的宏观应力影响小,这对器件的应用非常有利.加工实验表明:选用的工艺参数和抛光液对加工ZnSe晶体器件是成功的.     

X射线粉末衍射仪的测试及使用

X射线粉末衍射技术（XRD）是最重要的材料分析测试技术之一。本文结合作者的实际操作,简单的介绍了操作X射线粉末衍射仪的一些经验及其应用。     

铌酸钾晶体X射线衍射数据的测定

用衍射仪收集了KNbO_3晶体的粉末衍射数据,给出了d值大于0.8(?)的59条衍射数据和指标,对JCPDSX射线粉末衍射标准数据卡(9-156)进行了补充和修正。     

X-射线全谱拟合法测量钛白粉的晶粒度

采用X射线粉末衍射(XRD)全谱拟合的方法测量了钛白粉样品的晶粒度。选择步进式扫描采谱、结合全谱拟合法程序Topas中的基本参数法(FPA)软件全谱拟合,计算得到晶粒度参数,并与X射线粉末衍射线宽法、扫描电镜(SEM)分析结果进行对比。综合分析认为,X射线全谱拟合法计算钛白粉晶粒度无需标样、操作简便、分析快速准确,可以作为钛白粉的质量控制方法。     

用X射线衍射精确表征硅酸三钙多晶型

在1 500℃条件下,通过掺杂质量分数为0、0.6%及1.5%的MgO制备了T1、T3及M3型硅酸三钙(C3S)。使用不同分辨率的X射线衍射仪对样品进行分析。结果表明:不同晶型的C3S指纹区X射线粉末衍射特征峰存在明显差异,衍射峰的不同可以用于判定C3S晶型;当X射线衍射仪分辨率较低(仪器半高宽≥0.129°)且存在Ka2时,得到的C3S衍射峰特征不明显,存在重叠现象,无法判定C3S晶型;使用高分辨率衍射仪(仪器半高宽≤0.072°),无Ka2影响下,得到的衍射峰清晰,可以对C3S晶型进行精确判定。     

衍射端悬挂滤波片对硅X射线衍射图谱的影响

在衍射端分别悬挂镍、锰、铁、钨、锆、铑滤波片时,用Y-4Q衍射仪测量并分析了硅的X射线衍射图谱,结果表明锰作为滤波片除了对铜靶的"白色"X射线产生的深背景和衍射峰宽化有显著的积极影响外,对铜靶的Kβ线没有过滤功能;铁作为滤波片除了对铜靶的"白色"X射线产生的深背景和衍射峰宽化有微弱的积极影响外,对铜靶的Kβ线没有过滤功能;钨和锰作为滤波片对硅的衍射谱的影响几乎相同;锆和铑虽然原子序数差异大,但错和铑作为滤波片把铜靶的特征线几乎淹没了,把对衍射分析有用的射线全部被过滤掉了,显然不能作为铜靶的滤波片.     

焦化加热炉炉管失效分析

应用扫描电子显微镜、能谱分析以及X射线衍射仪对焦化加热炉炉管的高温腐蚀形貌,腐蚀物成分以及物相进行了分析,结果表明,尽管加热炉管用材是抗腐蚀性能和高温机械性能均良好的Cr5Mo钢,但由于炉膛操作温度过高,且燃料中含硫,炉管不但发生高温氧化腐蚀,还发生硫化腐蚀,使破坏加速,最终导致炉管失效。提出了预防措施。     

Manufacturing of silicon – Bioactive glass scaffolds by selective laser melting for bone tissue engineering

The irruption of additive manufacturing techniques opens the possibility to develop three-dimensional structures with complex geometries and high precision. In the current investigation a newly designed composite combining silicon (30, 40 and 50 wt%) with a bioactive glass and printed into scaffolds was obtained, using a direct selective laser melting (SLM) approach for the first time. Samples were computer-aided designed (CAD) to have cylindrical pores of 400 μm in diameter in order to be used as biomaterials for bone replacement. X – Ray diffraction was used to characterize the appearance of a new phase of pseudowollastonite precipitated by the partial devitrification of the glassy phase after the incidence of laser radiation. The mechanical behaviour of each composition was studied trough stress-strain curves, obtaining higher values of compressive strength as the silicon content increases. Scanning electron microscopy coupled to energy dispersive X – Ray spectroscopy (SEM-EDS) and Raman spectroscopy were used to study the bioactivity of each composite after soaking in the simulated body fluid (SBF) for 7 days, confirming this behaviour.     

Analysis of the structure and mass transport properties of nanocomposite polyurethane

In this work, nanocomposite adhesives obtained using an organically modified montmorillonite (OMM) in a polyurethane matrix were studied. The basal distance of OMM before and after mixing with the polyol and after curing was characterized by X‐Ray diffraction. The viscosity of polyols‐OMM systems was studied as function of shear rate in a cone‐plate rheometer in order to correlate the viscosity with the aggregation state of OMM. A simple model accounting for an apparent increase of rheological units size associated with the intercalation of macromolecules into OMM galleries is proposed. Curing was performed at room temperature for 1 week. The basal distances of crosslinked PU nanocomposites were obtained by X‐ray diffraction. The glass transition temperature, T_g, of PU nanocomposites, as measured using differential scanning calorimetry, increases with increasing volume fraction of OMM. Finally, the permeability to oxygen and water vapor of polyurethane clay‐nanocomposites was measured. The gas permeation through the composites was correlated to the volume fraction of the impermeable inorganic part of the OMM. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Evaluation of Using LaNi0.6Fe0.4O3–δ Contact Layer Between La0.6Sr0.4FeO3 Cathode and Crofer22APU Interconnect for Solid Oxide Fuel Cells

Interconnect‐cathode interfacial adhesion is important for the durability of solid oxide fuel cell (SOFC). Thus, the use of a conductive contact layer between interconnect and cathode could reduce the cell area specific resistance (ASR). The use of La_0.6Sr_0.4FeO₃ (LSF) cathode, LaNi_0.6Fe_0.4O_3–δ (LNF) contact layer and Crofer22APU interconnect was proposed as an alternative cathode side. LNF‐LSF powder mixtures were heated at 800 °C for 1,000 h and at 1,050 °C for 2 h and analyzed by X‐Ray power diffraction (XRD). The results indicated a low reactivity between the materials. The degradation occurring between the components of the half‐cell (LSF/LNF/Crofer22APU) was studied. XRD results indicated the formation of secondary phases, mainly: SrCrO₄, A(B, Cr)O₃ (A = La, Sr; B = Ni, Fe) and SrFe₁₂O₁₉. Scanning electron microscopy with energy dispersive X‐Ray spectroscopy (SEM‐EDX) and the X‐Ray photoelectron spectroscopy (XPS) analyzes confirmed the interaction between LSF/LNF and the metallic interconnect due to the Cr vaporization/migration. An increment of the resistance of ∼0.007 Ω cm² in 1,000 h is observed for (LSF/LNF/Crofer22APU) sample. However, the ASR values of the cell without contact coating, (LSF/Crofer22APU), were higher (0.31(1) Ω cm²) than those of the system with LNF coated interconnect (0.054(7) Ω cm²), which makes the proposed materials combination interesting for SOFC.     

微波合成掺锶羟基磷灰石

以SrCl2、Ca(NO3)2和(NH4)2HPO4为原料,采用微波法合成了掺锶羟基磷灰石。对制备的SrHAP进行元素含量分析,采用XRD对其结构进行了表征,并测定粉体产物的粒度。研究结果表明:采用微波法可以制备出元素组成接近原料计算化学计量比的掺锶羟基磷灰石;采用微波法可以快速得到结晶性好的SrHAP;掺锶量对微波合成的SrHAP的结构有显著影响;微波法比常规方法制备出的SrHAP粉体的粒度小。     

Structural changes of starch/polyvinyl alcohol biocomposite films reinforced with microcrystalline cellulose due to biodegradation in simulated aerobic compost environment

Starch/Polyvinyl alcohol (PVA) based biocomposite films reinforced with micro crystalline cellulose (MCC) (10 wt %) particles were prepared by solution casting method, incorporating glycerol as plasticizer. These biocomposite films were subjected to biodegradation at ambient temperature in a simulated aerobic compost pit. The extent of biodegradation of these films was studied in terms of weight loss. The corresponding changes in the structure of the films were observed using scanning electron microscopy, X‐Ray diffraction study, and differential scanning calorimetry. The melting point of PVA component of the biocomposite film shifted from 204 to 223°C with increase in biodegradation time and a remarkable difference was observed in their melt crystallization behavior. The unreinforced films also showed a similar trend, but the increase in the crystallinity of PVA was more pronounced in MCC reinforced films than that observed in the unreinforced ones. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Poly (diallyldimethylammoniumchloride)/sodium‐montmorillonite composite; structure,and adsorption properties

A cationic polyelectrolyte, poly (diallyldimethylammoniumchloride) (PDADMAC) and a smectite‐type layered silicate (sodium activated montmorillonite clay (Sodium‐Montmorillonite, NaMt)), intercalated composites (PDADMAC/NaMt) were prepared. Basal spacings (d001) of NaMt in composites were measured by X‐Ray diffraction analysis (XRD). Ultrasonic addition of low molecular weight PDADMAC into the NaMt structure (at very low concentration and very low PDADMAC(g)/NaMt(g) ratios) resulted in good adsorbing properties both for positively and negatively charged dyes. The adsorption kinetics of the prepared composites both for negatively charged [remazol black (RB)] and positively charged [methylene blue (MB)] reactive dyes were investigated. The RB adsorption efficiency of the positively charged composite is approximately three times that of the pure NaMt while its MB adsorption efficiency is as good as that of pure NaMt. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of Eri silk fibre on the physical characteristics and dyeing properties of Eri silk/cotton blended yarn

Different blending ratios of Eri silk and cotton fibres were prepared. The optimum bleaching condition chosen for the blends containing 0–25% silk content was the oxidative bleaching method, whereas the blends at 50–100% should be bleached using the two‐stage bleaching method (oxidative bleaching followed by reductive bleaching). These conditions did affect the force–displacement characteristics of the fibres with no yield point. X‐Ray diffraction results showed that the percentage of crystallinity of the cotton yarn tended to increase after bleaching, whereas the percentage of crystallinity of the Eri yarn decreased marginally. Dyeing properties of the blended yarns were investigated using warm‐dyeing reactive dyes. Percentage exhaustion and the colour yield of the blends tended to decrease with the increasing silk content. Shade variation was observed on the yarns at different blend ratios. This was expected to be caused by the different physical nature of Eri silk and cotton fibres. Consequently, the dye uptake and visual shade of each dye on the two fibres were different.     

The penetration of chlorides into hardened cement pastes

The penetration of chloride ions into hardened cement pastes (hcp) has been measured by chemical analysis, X Ray diffraction and thermal analysis. The penetration of chloride depends on the permeability; thus the greater the w/c ratio the greater is the penetration.The concentration of chloride in the hcp is dependent on the concentration of the sorrounding solution.The chloride ions react with the anhydrous tricalcium aluminate in the unhydrated cement left in the hcp but not with the complex hydrated calcium aluminate salts including ettringite.Calcium mono-chloroaluminate hydrate is formed, but not all the chloride which penetrates reacts to form this mineral. The quantity of chloroaluminate formed is independent of the chloride concentration in the hcp.From a study of the pore size distribution of the hcp by mercury intrusion porosimetry it is deduced that the penetrating chloride reduces the sizes of the small pores thus reducing the permeability.     

Processing and properties of PLA/thermoplastic starch/montmorillonite nanocomposites

Thermoplastic starch (TPS) and polylactic acid (PLA) were compounded with natural montmorillonite (MMT) using a twin‐screw extrusion process to investigate the structure and properties of these nanocomposites and to examine the use of water to enhance clay exfoliation. Tensile and essential work of fracture measurements were performed on standard dumbbell shape samples and on double notched samples to determine the effect of MMT and PLA/TPS interfacial modification on the mechanical and fracture properties of the materials. The nanocomposite structure was investigated using X‐Ray diffraction, transmission electron microscopy, and atomic force microscopy. Differential scanning calorimetric analysis was performed on the materials to determine the effect of TPS and MMT on PLA crystallization and physical aging. It was found that the TPS can intercalate the clay structure and that the clay was preferentially located in the TPS phase or at the blend interface. This led to an improvement in tensile modulus and strength and to a reduction in fracture toughness. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers