无机聚合絮凝剂的结构研究

本文用广角度Ｘ射线散射（ＷＡＸＳ）和径向分布函数（ＲＤＦ）方法对聚合硅硫酸铝钾ＴＸ２０３絮凝剂的结构进行了分析。ＷＡＸＳ和ＲＤＦ分析指出：该絮凝剂是一种有序尺寸（Ｄ）约为２２～２５Ａ非晶固体。它是由有序周期（ｒ、）≌１２－１４Ａ的中程有序畴组成的,而这些有序畴又是由三种结构单元,即四面体「ＳＯ４」,「ＡｌＯ４」（０＝Ｏ,ＯＨ）和八面体「ＡｌＯ６」（Ｏ＝Ｏ,ＯＨ）组成的。Ｄ／ｒ１＝２～３,因此ＴＸ２     

镍钨磷合金电结晶机理及其镀层结构与显微硬度

应用循环伏安,恒电位阶跃和Ｘ射线衍射（ＸＲＤ）等方法了Ｎｉ－Ｗ－Ｐ合金电沉积特点和镀层结构与显微硬度,结果表明,在以柠檬酸铵为配体的溶液中,Ｎｉ－Ｗ－Ｐ合金 层较Ｎｉ－Ｗ合金有较低的电化学活性,根据电位阶跃的ｉ－ｔ曲线分析表明,在玻碳电极上Ｎｉ－Ｗ－Ｐ合金电结晶过程遵从扩散控制瞬时成核三维成长模式进行,随着过电位的增加,电极表面上晶核数增多,ＸＲＤ试验结果表明,Ｎｉ－Ｗ－Ｐ合金镀层呈现明显的非晶态特征,所获得的Ｎｉ－Ｗ－Ｐ合金电沉层的显微硬度在４５０ｋｇ．ｍｍ＾－２左右。     

Fe-W非晶镀层的磷化及在NaCl溶液中的腐蚀行为

ＦｅＷ非晶态合金镀层在酸性溶液中具有高耐蚀性能,但在中性和碱性溶液,特别是在氯化钠溶液中耐蚀性能差［１］,如在３０℃、１ｍｏｌ／ＬＨＣｌ溶液中,ＦｅＷ非晶镀层的腐蚀速率约为不锈钢ＳＵＳ３０４的１／１５;在６０℃、０５ｍｏｌ／ＬＨ２ＳＯ４溶液中约...     

p—Si上电沉积Ni—W—P薄膜的结构与热稳定性

研究了ｐ－Ｓｉ上恒电流沉积Ｎｉ－Ｗ－Ｐ合金薄膜组成与结构的关系，讨论了镀层的组成、结构随沉积时间的变化．测定了非晶合金的晶体结构随热处理温度的改变以及ＤＴＡ曲线，结果表明，非晶Ｎｉ－Ｗ－Ｐ合金在晶化过程中形成两个纳米超微晶相，非晶Ｎｉ－Ｗ－Ｐ薄膜的热稳定性远高于通常使用的非晶Ｎｉ－Ｐ薄膜．     

Al－Mn合金镀层的组成结构及其耐蚀性

研究了在低温熔盐中（低于２００℃）电沉积Ａｌ－Ｍｎ合金镀层成分的控制,镀层化学组成与结构之间的关系以及镀层的耐蚀性能．提出影响镀层锰含量的主要因素是熔盐中锰离子的浓度．镀层含锰量在２５～４０（ｗｔ）％之间可形成非晶态结构．实验表明,Ａｌ－Ｍｎ合金镀层在０．５ｍｏｌ／ＬＨ＿２ＳＯ＿４熔液及ＮａＣｌ溶液中具有优良的耐蚀性,非晶态结构的Ａｌ－Ｍｎ合金镀层的耐蚀性更为优异．     

Al—Mn合金镀层的组成结构及其耐蚀性

研究了在低温熔盐中（低于２００℃）电沉积Ａｌ－Ｍｎ合金镀层成分的控制，镀层化学组成与结构之间的关系以脑镀层的耐蚀性能，提出影响镀层锰含量的主要因素是熔盐中锰离子的浓度，镀层含锰量在２５－４０（ｗｔ）％之间可形成非晶态结构，实验表明，Ａｌ－Ｍｎ合金镀层在０．５ｍｏｌ／ＬＨ２ＳＯ４溶液及ＮａＣｌ溶液中具有耐蚀性，非晶态结构的Ａｌ－Ｍｎ合金镀层的耐蚀性更为优异。     

TiO2负载非晶态合金NiB催化剂的制备、表征及HDS动力学研究

用等体积浸渍－还原法制备了负载型的ＮｉＢ／ＴｉＯ２（Ｂ／Ｎｉ＝５：１摩尔比）非晶态合金,并在相同条件下制备了ＮｉＢ／Ａｌ２Ｏ３（Ｂ／Ｎｉ＝５：１摩尔比）与之对照。用ＸＲＤ,ＳＥＭ和ＴＥＭ等表征方法比较了样品的非晶性质,在脉冲反色谱装置上以噻吩的ＨＤＳ反应为探针测定了ＮｉＢ／ＴｉＯ２、ＮｉＢ／Ａｌ２Ｏ３的反应活性,进行了动力学研究。结果证明,ＮｉＢ／ＴｉＯ２的低温活性远高于ＮｉＢ／Ａｌ２Ｏ３,其原因     

Sm2(Fe,Al,Zr)17C1.5合金微结构与磁性能的关系

用Ｘ射线衍射仪,振动样品磁强计,扫描电镜及透射电镜对Ｓｍ２Ｆｅ１５．３Ｚｒ０．２Ａｌ１．５Ｃ１．５合金的微结构和磁性进行了研究。合金主要由２／１７相、α－Ｆｅ相和ＺｒＣ要组成。     

液态结构与Al-Fe-Ce合金短程有序的相关性

采用Ｘ射线衍射技术研究了Ａｌ＿０．９Ｆｅ＿０．１和Ａｌ＿０．９Ｆｅ＿０．０５Ｃｅ＿０．０５合金的液态结构及Ａｌ＿０．９Ｆｅ＿０．０５Ｃｅ＿０．０５合金的非晶结构,并采用ＤＳＣ热分析研究了非晶合金的晶化行为．发现液态和非晶态合金的结构因子曲线上都存在明显的预峰,所对应的化学短程有序结构随温度降低,尺寸不断增大,但其结构单元的尺寸保持不变．Ｃｅ的加入使液态合金中化学短程有序及其结构单元的尺寸增大,并有利于原子间交互作用增强,从而提高非晶形成能力．预峰所对应的化学短程有序结构单元是以Ｆｅ原子为中心的二十面体准晶结构,这种结构在液态已形成,并保留在非晶中．     

液态结构与Al-Fe-Ce合金短程有序的相关性

采用Ｘ射线衍射技术研究了Ａ１０．９Ｆe０．１和Ａ１０．９Ｆe０．０５Ｃe０．０５合 金的液态结构及Ａ１０．９Ｆe０．０５Ｃe０．０５Ｃe０．０５合金非晶结构,并采用Ｄ ＳＣ热分析研究了非晶合金的晶化行为,发现液态和非晶态合金的结构因子曲线上都存在明显的预峰,所对应的化学短程有序结构随温度降低,尺寸不断增大,但其结构单元的尺寸保持不变,Ｃe的加入使液态合金中化学短程有序及其结构单元的尺寸增大,但其结构单元的     

Mechanical and corrosion behavior of amorphous and crystalline electroless Ni–W–P coatings

Two types of electroless Ni–W–P coatings: nanocrystalline with low P and amorphous with higher P content are investigated. Scanning probe microscopy is applied to study their morphology. Textured nanocrystalline coatings consist of coarse pyramids built of nanometer thick lamellas. The surface morphology of amorphous coatings is much finer and uniform. Nanohardness of all coatings depends on W content. Microhardness is increasing during the heat treatment up to 350 °C due to nickel phosphide precipitation affected by tungsten also. The wear resistance of nanocrystalline Ni–W–P coatings is much higher than that of amorphous in spite of the similar tungsten content in both. Lower corrosion resistance of amorphous Ni–W–P coatings is found by weight loss method during long-term immersion in 5 % NaCl. Electrochemical tests by potentiodynamic polarization curves in two model corrosion media—solutions of 0.5 M H₂SO₄ and 5 % NaCl—are performed. The corrosion of bi-layered Ni–W–P/Ni–P and Ni–W–P/Ni–Cu–P deposits on mild steel is also investigated. The results prove that an electroless Ni–W–P coating on mild steel extremely improves its mechanical and corrosion behavior. It is demonstrated that in addition to deposit’s structure and composition, the distribution and chemical state of alloy ingredients are also responsible for its properties.     

p－Si上电沉积Ni－W合金薄膜

利用恒电流沉积法，在ｐ－Ｓｉ上制备出不同Ｗ含量和不同结构的Ｎｉ－Ｗ薄膜，研究了镀液温度，ｐＨ值，电流密度对镀层组成的影响，结果表明，提高温度有利于获得高Ｗ含量的合金．随着镀层中Ｗ含量的增加，Ｎｉ面心立方晶格ｆ．ｃ．ｃ发生正畸变，晶粒平均尺寸变小，当Ｗ含量达到５６％以上时，晶粒小于２ｎｍ，薄膜呈非晶态结构．     

非晶态Ni-W-B合金的电沉积及其热处理前后的性能

To strengthen the properties of Ni-W alloy, dimethylamine borane （DMAB） was added to an alloy Ni-W electrolyte solution and a ternary Ni-W-B alloy was electrodeposited. The electrodeposition, crystallographic structure, surface morphology, heat treatment and corrosion resistance, of the alloy were studied by DSC, XRD, SEM and electrochemical techniques. The results showed that the structure of the alloy was greatly affected by the cooperation of boron compound. DSC experiment combined with X-ray diffractometry indicated that the obtained Ni-W-B alloy was still in amorphous structure although W content in the alloy was decreased by the addition of DMAB. After heat treatment at 400 ℃ for 1 h, the microhardness was increased from 612 to 947 kg.mm^-2 that was com- parative to Cr coating. The appearance of the as-plated coating was in f＇me and slice grains and kept almost no change after heat treatment. In w=0.03 NaC1 solution the as-plated coating presented very good corrosion resistance. After the coating was heat-treated its corrosion resistance was enhanced.     

Effect of P codeposition on the structure and microhardness of Co–W coatings electrodeposited from gluconate bath

Effects of addition of P to Co–W coatings from gluconate bath using direct current (DC) and pulse current (PC) methods have been investigated in this study. Co–W–P coatings with different P concentrations are prepared by varying hypophosphite concentration in the bath. Current efficiency of the Co–W–P electrodeposition is lower than that for Co–W coatings. Increase in NaH₂PO₂ concentration increases the cobalt content significantly and decreases the tungsten content drastically. Co–W–P coatings display ‘cauliflower‐like’ morphology and roughness of the coatings increases with increasing P content. As‐deposited Co–W–P deposits are amorphous while heat treatment at different temperatures has rendered them crystalline with the precipitation of stable species like, Co₃W, Co₂P, etc. Unlike Co–W coatings, Co–W–P shows two‐step crystallization in differential scanning calorimetry (DSC) and on heat treatment, which is similar to the behavior of Co–P electrodeposited from gluconate baths. Moreover, inclusion of phosphorous and heat treatment have led to significant increase in microhardness of the Co–W–P coatings. X‐ray photoelectron spectroscopy (XPS) studies provide a detailed insight into the nature of Co, W and P species in as‐deposited and sputtered coatings. Microhardness of the heat‐treated coatings is higher than the as‐deposited counterparts and is comparable with that of hard chromium. Copyright © 2016 John Wiley & Sons, Ltd.     

Heat-resistant alloys based on intermetallic Co<Subscript>3</Subscript>(Al,W)

The structures and phase compositions of a series of Co–9 at % Al–x at % W alloys (where x = 4.6, 6.8, 8.5, 10.0, 12.6) have been studied. All of them are dominated by the structure γ + γ′, with the content of other phases (the μ phase and the phase D0₁₉ based on Co₃W) being insignificant. With increasing tungsten content of the alloy (to 10 at % W), the volume fraction of the γ′ phase increases, and so does its degree of long-range order. The alloy that is optimal in structure and mechanical properties has the composition Co–8.2 at % Al–8.5 at % W. The dissolution range of the γ′ phase was determined as 920–1054°C. Young’s moduli of cobalt alloys exceed E of commercial nickel-based superalloys. The samples of the studied alloys are in the ferromagnetic state with a Curie temperature of 870°C. With increasing tungsten content of the alloy, its saturation magnetization decreases and the coercive force increases. The coercive force is minimal in an as-cast sample and increases as it is subjected to deformation or heat treatment.     

One‐step electrodeposition of amorphous carbon films containing WO3 with high conductivity and good wettability

Tungsten trioxide‐incorporated hydrogenated amorphous carbon (WO₃/a‐C:H) films have been fabricated on a single‐crystal silicon wafer by liquid phase electrodeposition using methanol as carbon source and tungsten carbonyl as incorporated reagent. The morphology, composition and structure of the films have been investigated by SEM, XPS, Raman scattering spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscope (TEM), respectively. The effects of WO₃ incorporation on the electrical and wetting properties were studied in detail. The characterization results showed that tungsten trioxide nanocrystalline particles with diameters in the range of 10–20 nm were homogenously embedded in the amorphous carbon films. Also, the electrical conductivity and wetting ability of the films were strongly improved due to the contribution of the tungsten trioxide. Copyright © 2010 John Wiley & Sons, Ltd.     

Electronic structure and catalytic behavior of tungsten carbides

The electronic structure of tungsten carbide was investigated by EHMO semiempirical method. The most stable structure of the carbide was predicted on the basis of binding energy calculations. The W-C bonding is covalent in nature with some charge transfer from the W to the C atoms. The increase in the occupancy of the d shell of the W atoms and the position of the Fermi level may account for the platinum-like catalytic behavior of tungsten carbide.     

等离子体增强化学气相沉积法制备WO3-x/C复合材料及其储锂性能研究

三氧化钨(WO_3)凭借其在锂离子电池中较高的理论比容量(～700mAh·g~(-1))以及廉价易得的特性而引起了科研工作者广泛的研究兴趣,然而其相对较差的导电性以及在循环过程中所发生的较大体积变化导致其倍率性能和循环性能并不理想。为了增强其导电性,减缓体积变化所带来的负面影响,本文采用等离子体增强的化学气相沉积法成功地在所制备的WO_(3-x)纳米片上包覆含有氮元素掺杂的无定形碳。氮掺杂碳的包覆可以有效降低循环过程中发生的较大体积变化问题,而且可以提供更多的位点供锂离子进行嵌入/脱嵌。电化学测试表明,所制备的WO_(3-x)/C电极相比于WO_(3-x)电极和商业WO_3电极,展现出更好的倍率性能和循环性能。动力学模拟与计算表明,经过碳包覆的WO_(3-x)/C电极具有更小的电荷转移电阻和更快的锂离子扩散速率,从而有效提升其电化学性能。     

Quantitative Raman and ESCA characterization of titania supported tungsten catalysts

Summary The distribution of supported species in a series of W/TiO₂ catalysts (1.8 – 28 wt% WO₃) has been determined by Raman and X-ray photoelectron spectroscopy (XPS, ESCA). The results show that three tungsten species are present on oxidic W/TiO₂ catalysts. A tungsten interaction species is formed almost exclusively for catalysts with W loadings lower or equal to 6.7 wt% WO₃. WO₃ is observed above 6.7 wt% WO₃. For W loadings higher than 10 wt%, a disordered W species W_DS is also present. The amounts of W_DS and WO₃ increase with increasing W content above 10 wt% WO₃.Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday     

Tungsten allylimido complexes Cl4(RCN)W(NC3H5) as single-source CVD precursors for WNxCy thin films. Correlation of precursor fragmentation to film properties

A mixture of the tungsten allylimido complexes Cl(4)(RCN)W(NC(3)H(5)) (3a, R = CH(3) and 3b, R = Ph) was tested as a single-source precursor for growth of tungsten nitride (WN(x)) or carbonitride (WN(x)C(y)) thin films. Films deposited from 3a,b below 550 degrees C contained amorphous beta-WN(x)C(y), while those deposited at higher temperatures were polycrystalline. Film growth rates from 3a,b ranged from 5 to 10 A/min over a temperature range of 450-650 degrees C, and the apparent activation energy for film growth was 0.15 eV. A plot of the E(a) values for deposition from Cl(4)(RCN)W(NR') [R' = Ph, (i)Pr, allyl] against the N-C imido bond strengths for the analogous amines R'NH(2) is linear, implicating cleavage of the N-C bond as the rate-determining step in film growth. The correlation of mass spectral fragmentation patterns for Cl(4)(RCN)W(NR') with film properties such as nitrogen content supports the significance of facile N-C bond cleavage in film growth.