应用选择性磁罩盖法磁选分离镍黄铁矿与蛇纹石

针对镍黄铁矿和蛇纹石浮选难分离,提出采用磁罩盖法进行磁分离.结果表明,控制一定的矿浆物化条件,随着磁种磁铁矿的添加,镍黄铁矿的磁选回收率随之升高,而蛇纹石的回收率基本保持很低,可实现两者的良好分离.人工混合矿分离结果表明,磁种质量分数为5%时,获得的精矿Ni品位为19.89%,回收率为92.46%,MgO质量分数为4.72%;X射线衍射和扫描电镜分析结果显示磁铁矿在镍黄铁矿表面产生了罩盖,在蛇纹石表面未产生明显的罩盖;Zeta电位测试和DLVO理论计算结果表明,添加六偏磷酸钠后,蛇纹石表面电性由正变负,而对镍黄铁矿和磁铁矿表面电性未产生显著影响,从而使磁铁矿与蛇纹石间的相互作用变为排斥,而与镍黄铁矿之间仍为吸引,因而磁铁矿选择性罩盖在镍黄铁矿表面,增强其磁性,实现与蛇纹石的磁分离.      

X射线Φ扫描及其在高温超导薄膜分析中的应用

Ｘ射线φ扫描及其在高温超导薄膜分析中的应用常世安，陈岗峰，马平，杨坚，古宏伟，袁冠森（北京有色金属研究总院１０００８８）关键词：Ｘ射线衍射，高温超导薄膜Ｘ射线衍射仪的常规θ－２θ扫描只能对平行于试样表面特定晶面进行检测￣［１］．而无法区别是单晶、外延...     

锑化镓材料表面氧化机理的研究

利用扫描透射电子显微镜、Ｘ射线衍射和Ｘ射线光电子能谱检测了锑化镓晶片表面氧化层的成分和结构，研究了锑化镓材料表面氧化物的形成过程。     

理化之窗

理化之窗用于簿膜及表面分析的Ｘ射线分析仪器１．Ｘ射线超晶格结构测定装置ＳＬＸ采用双晶法（包括晶体限束管）测定回摆曲线，从而可进行完整性评价、外延层膜厚的估算及晶格失配度的计算。还可进行超晶格结构参数的分析计算、错向角和晶格畸变的计算及晶格常数的精密测...     

钐对Ni-B/SiO_2非晶态合金催化剂的催化性能及表面性质的影响

本文采用脉冲技术以己二腈气固相常压加氢为探针反应，研究了化学还原法制备的非晶态合金催化剂Ｎｉ－Ｂ、Ｎｉ－Ｂ－Ｓｍ的加氢活性及抗硫性能。并用Ｘ射线衍射（ＸＲＤ）、差示扫描量热分析（ＤＳＣ）、电感耦合等离子发射光谱（ＩＣＰ）、Ｘ射线光电子能谱（ＸＰＳ）、程序升温还原（ＴＰＲ）和程序升温脱附（ＴＰＤ）等手段对催化剂的结构、组成与表面性质进行了表征。实验结果表明，在此催化剂上该反应符合Ｌａｎｇｍｕｉｒ－Ｈｉｎｓｈｗｏｏｄ机理，活性中心座数为２。钐的加入可提高Ｎｉ－Ｂ非晶态合晶的热稳定性、催化活性和抗硫性。其原因可能是钐的给电子效应使合金的组成及表面性质发生了变化。     

某高钙粉煤灰理化性质研究

本文通过X-射线荧光、X-射线衍射、扫描电子显微镜、燃烧前原煤煤粉与未燃炭红外光谱对比分析、粒度分析等得出:此某高钙粉煤灰中主要物质为Ca SO4、Al2O3、Si O2及残炭;残炭表面被无机矿物质罩盖严重;燃烧促使煤粉中大量疏水官能团消失;试样中-20μm粒级的含量约占47%,微细粒含量大;通过接触角的测量,发现其精选精炭的接触角只有36.2°,定量得出此高钙粉煤灰天然可浮性差。     

强搅拌调浆在金川硫化铜镍矿浮选中的作用机制研究

通过浮选试验、粒度分析测试和扫描电镜(SEM)分析,研究强搅拌调浆在金川硫化铜镍矿浮选中的作用,并考察其作用机制。浮选试验结果表明:强搅拌调浆能够提高金川硫化铜镍矿的浮选指标,强搅拌的时间越长,强度越强,金川硫化铜镍矿的浮选指标越好。固定调浆时间为20 min,当调浆强度从1950增加到2800 r·min-1时,镍的浮选回收率从81%增加到87%。金川硫化铜镍矿中的蛇纹石矿泥与硫化矿物颗粒表面电性相反,容易通过静电吸引作用吸附在硫化矿物表面形成矿泥罩盖层,细颗粒矿泥的罩盖阻碍了硫化矿物颗粒和气泡的粘附,降低了硫化矿物的浮选回收率。粒度测试和扫描电镜分析结果证实了金川硫化铜镍矿中的粗颗粒硫化矿物表面罩盖有细颗粒矿泥,矿泥的主要成分为蛇纹石等含镁硅酸盐矿物。对矿浆进行强搅拌调浆能够脱附硫化矿物表面罩盖的蛇纹石矿泥,蛇纹石矿泥粒度越粗,越容易从硫化矿物表面脱附,而粒度极细的蛇纹石矿泥较难脱附。强搅拌的强度越强,时间越长,硫化矿物表面罩盖的蛇纹石矿泥数目越少,越容易与浮选气泡粘附,浮选回收率越高。     

含Sn高磁感(Hi-B)取向硅钢脱碳退火板面氧化层研究

应用Ｘ射线荧光能谱、红外线吸收光谱、Ｘ射线衍射和Ｘ射光子能谱、俄歇电子能谱等手段，研究了含Ｓｎ－Ｈｉ－Ｂ硅钢脱碳退火板面“膜”的成分及其分布。证实了“膜”即氧化层，分析了在受上力时“膜”即剥离的原因。文中还给了了Ｓｎ－Ｈｉ－Ｂ硅钢板脱碳退火后表面氧化量的宏观度量方法和几种工艺条件下所形成的诸氧化物的含量。     

金刚石表面镀复金属处理的研究

对金刚石表面采用真空蒸镀方法，镀复铬与钛，达到表面金属化后，并进行热护散处理生成碳化物型的中介层。利用Ｘ射线衍射和扫描电镜等进行结构分析，并检验其在金属烧结复合体中的机械性能与使用效果。     

X射线法观察材料成形过程

Ｘ射线法观察材料成形过程据（ＴｈｅｊｏｕｒｎａｌｏｆＳｃｉｅｎｃｅ）报导，一个科学家小组开发成功一种Ｘ射线分析新方法，使他们能逐步观察陶瓷复合材料成形过程中的三维尺寸和显微结构，这种新方法称为层析Ｘ射线摄影显微术，比医学Ｘ射线方法具有更高的分辨率，在...     

X-PEEM Study on Surface Orientation of Stylized and Rubbed Polyimides

X-ray photoelectron emission microscopy (X-PEEM) was used to study the surface orientation of stylized and rubbed polyimide thin films. Using soft X-rays produced by a synchrotron light source, this technique combines high spatial resolution imaging with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to yield information on the surface orientation of the films. Stylizing is an ideal model of the rubbing process since the local stress acting on the polyimide to orient the molecules can be calculated. The minimum normal stress necessary to orient the surface of BPDA-PDA films was found to be 45 MPa much lower than the bulk yield stress of 200-300 MPa. Studies of the polyimide films oriented by the conventional rubbing method showed lateral inhomogeneities in the orientation of the polymer at the surface.     

Electrochemistry ofthiobacillus ferrooxidans interactions with pyrite

A cyclic voltammetry technique was used to study the interactions of mineral-pyrite during bioleaching with the bacteriumThiobacillus (T.) ferrooxidans over its entire growth cycle. Invariably, the pyrite surface drastically changed its properties on the second day of bacterial rowth (bioleaching). After 2 days, the cyclic voltammograms (CVs) were insensitive to convective diffusion produced by stirring. The product layer was examined by scanning electron microscopy (SEM), X-ray diffraction, and chemical analysis. The SEM study revealed an extremely high density of bacteria on the pyrite surface. The high density of bacteria, along with the solid reaction products formed on the pyrite surface, created conditions for crack/pore diffusion, explaining why the CVs became insensitive to convective diffusion (stirring) in solution. X-ray diffraction study confirmed jarosite as a product layer. A mechanism is proposed by whichT. ferrooxidans cells serve as nucleation sites for jarosite formation. Formerly Graduate Student, College of Mines and Earth Resources, University of Idaho.     

Fabricating Buffer Layers for YBa2Cu3Oy Coated Conductor by Surface Oxidation Epitaxy

Coated conductor of YBa2Cu3Oy(YBCO) withhighsuperconducting critical current (IC)is promisingfor many applications . To decrease weak link andlarge grain boundary angle it is i mportant to achievebiaxial textured YBCO.Sofar ,a fewtechniques havebeen appli…     

Promotional effect of CO pretreatment on CuO/CeO2 catalyst for catalytic reduction of NO by CO

The CuO/CeO2 catalysts were investigated by means of X-ray diffraction(XRD),laser Raman spectroscopy(LRS),X-ray photoelectronic spectroscopy(XPS),temperature-programmed reduction(TPR),in situ Fourier transform infrared spectroscopy(FTIR) and NO+CO reaction.The results revealed that the low temperature(150 °C) catalytic performances were enhanced for CO pretreated samples.During CO pretreatment,the surface Cu+/Cu0 and oxygen vacancies on ceria surface were present.The low valence copper species activated the adsorbed CO and surface oxygen vacancies facilitated the NO dissociation.These effects in turn led to higher activities of CuO/CeO2 for NO reduction.The current study provided helpful understandings of active sites and reaction mechanism in NO+CO reaction.     

Surface Integrity Assessment Upon Electric Discharge Machining of Die Steel Using Non-Destructive Magnetic Barkhausen Noise Technique

Surface integrity characterization of manufactured component is very important as it significantly affects the in-service performance of the component. Till now, surface integrity was evaluated using conventional measurement technique like microhardness tester, X-ray diffraction, optical microscopy and surface roughness tester. But, this technique being laboratory based cannot be used for in-service monitoring of the surface integrity. The present study focuses on the characterization of surface integrity upon electric discharge machined sample using non-destructive magnetic Barkhausen noise technique. Electric discharge machining was performed in die-sinking mode on die steel using copper–tungsten electrode (negative polarity). Experiment was performed by selecting different levels of peak current, gap voltage and pulse on time. Surface integrity characteristics like microhardness change, residual stress, microstructural alteration and surface roughness were analysed using microhardness tester, X-ray diffraction, optical microscopy and surface roughness tester, respectively, and were then correlated with magnetic parameter like root mean square value and peak value obtained from Barkhausen noise signal. The results show a good correlation between magnetic parameter (RMS and Peak value) of Barkhausen noise with the microhardness and surface roughness of the machined sample.

     

渗氮烧结的YT15梯度硬质合金微观组织

采用渗氮烧结工艺制备YT15梯度硬质合金,利用扫描电镜、能谱仪、X射线衍射等手段,研究该合金的表面微观组织,并对其表面梯度层的形成进行热力学分析.结果表明Ti元素与N元素之间较强的结合力驱动Ti元素向外和Co元素向内定向迁移,在合金表面形成厚度为10 μm的富含Ti(C,N)相的梯度层.实验结果与热力学分析均表明氮气氛...     

Persistence of superficial contamination of rolled steel during successive treatments up to the formation of a galvanneal coating

With the assistance of X-ray photoelectron spectroscopy (XPS) the outer surface (approx. 3 nm) of IF steels that have to react with zinc in order to produce the galvanneal coating has been characterized. In particular, attention has been focused on the nature and content of carbon-rich impurities on the surface of these steels, which have been cold rolled and annealed. The study has found a type of superficial contamination in which the elements C and Ca are associated and which persists throughout the annealing and galvannealing processes. In this case, the contamination surprisingly seemed to shift from the surface of the steel substrate to the otuer surface of the galvanneal coating. The present communication is intended to report this unexpected fact.     

粉末冶金Ti-Al合金表面多孔氧化膜的制备

以含CrO3的氢氟酸水溶液为电解液,采用阳极氧化法于粉末冶金Ti-Al合金表面制备多孔氧化膜。采用场发射扫描电镜(SEM)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)对多孔氧化膜的形貌和结构进行分析,研究电解液各组份及浓度、阳极氧化电压对多孔氧化膜的影响规律,并利用电化学测试技术探讨多孔氧化膜的成膜机理。结果表明:合金在不含CrO3的HF电解液中阳极氧化不能获得多孔氧化膜,而是发生严重的腐蚀溶解。电解液中HF浓度和电压均影响氧化膜的形貌,在HF含量为0.2%时可获得规则的多孔氧化膜,孔径在50nm左右;当氧化电压为10V时形成的多孔氧化膜规则性较好,电压增大时多孔氧化膜结构遭到破坏。氧化膜中主要含有无定型的TiO2、Al2O3以及少量晶态的Ti2O、单质Al。多孔氧化膜的生长过程包括阻挡层的形成、多孔氧化膜的初始形成和多孔氧化膜的稳定生长3个阶段。     

Defects studies of semiconductor materials

The nature and cause of defects in bulk and epitaxial semiconductor material are determined by combining the information obtained from several different techniques. Etch pit count, X-ray diffraction for measurement of precise cell parameter, X-ray topography, scanning electron microscopy (SEM), and electron microprobe analysis (EMA) are used to supplement each other. It is shown that more than one technique is necessary for a complete understanding of the defects. The approach is illustrated by three example: 1) The homogeneity study of GaAs wafers with equivalent doping but prepared under different conditions shows an excellent agreement between the amount of dislocations per sq cm obtained by the etch pit count, X-ray topography, and the degree of inhomogeneity as determined by variation ina ₀ measurements. 2) The defects studies of the GaAsP epitaxial layer by X-ray topography, precise cell parameter measurements, SEM, and EMA indicate that the crystallographic defects are induced by misorientation during the growth process and by surface contamination of the substrate. 3) The examination of the surface defects of an etched silicon wafer by optical microscopy and X-ray topography indicates the presence of precipitates. Upon further studies using SEM and EMA it is shown that the defects are not precipitates but hillocks produced by surface contamination prior to the etching process.     

Microstructural Mechanisms of Early Age Cracking Behavior of Concrete: Fracture Energy Approach

This paper presents findings from a study directed at identifying key properties of ingredient materials that are influential on the early age cracking behavior of concrete, with an emphasis on the effects of aggregate size, aggregate morphologies, and water-cement ratio (w/c). Fracture energy (GF) was determined using a wedge-split test configuration for concrete samples at the age of 12?h. Based on image analysis, three signature morphologies of aggregate particles, i.e., the angularity, surface texture, and surface area, were quantitatively determined in terms of developed angularity index (AI), surface texture (ST) index, and surface area (SA) measurement, respectively. The high consistency between GF and aggregate SA of the concrete samples suggests that the interfacial transition zone (ITZ) at the cement paste-aggregate interface is the critical location that primarily accommodates the 12?h cracking of concrete. The critical role of ITZ in the early age cracking of concrete was further confirmed by its microstructural and chemical features under scanning electron microscopy/energy dispersive X-ray spectroscopy.