Fe-B非晶态合金中电子转移问题的DFT研究

利用一系列原子簇模型 Fen B2 (n=1～ 4)对 Fe- B非晶态合金的电子结构 ,用 DFT方法进行高水平的量子化学计算 ,结果表明 ,模型体系 Fen B2 (n=1～ 4)中 ,B原子供给 Fe原子电子 ,这与非晶态合金的实验结果一致 ;模型体系不存在类似于 Ni- B非晶态合金中 B- B近距离接触 ,为了比较 ,也选择了单硼原子簇 Fen B(n=1～ 4)模型 ,计算结果与实验不符 ,说明双硼原子簇模型 Fen B2 能在一定程度上反映 Fe- B非晶态合金的局域结构特征。     

Fe-P非晶态合金局域结构和电子性质的理论研究

根据Fe-P非晶态合金结构的短程有序、Fe和P之间具较强化学作用和结构中可能存在P-P相互作用的实验事实,选择了单磷原子簇模型FenP(n=1～6,8)和双磷原子簇模型FenP2(n=1～4),用密度泛函理论方法对其进行计算。结果表明,在单磷模型体系中,Fe原子供给P原子电子;而在双磷模型体系中,电子转移方向发生变化,P原子供给Fe原子电子,这与Fe-P非晶态合金的实验结果一致,说明单磷和双磷原子簇模型能较全面反映Fe-P非晶态合金的结构特点。     

非晶态合金Ni-Fe-B体系成键及电子性质的理论研究

结合文献报道,Ni／Fe=1：1时非晶态合金Ni-Fe-B体系对某些加氢反应的催化活性和选择性较好,设计一系列Ni、Fe等比例的双硼原子簇Ni2Fe2B2的各种可能构型,利用DFT方法在B3LYP／Lanl2dz水平下进行全参数优化和频率验证。分析优化结果中知：原子簇Ni2Fe2B2单重态有四个稳定构型、三重态有三个稳定构型,三重态能量均低于单重态能量;Ni-B、Fe-B键间有强烈相互作用;Ni、Fe原子带负电荷,B原子带正电荷,电子从类金属向金属转移,类似于非晶态合金Ni-B、Fe-B、Co-B体系的电子行为。     

组织结构对Co-Ni-P薄膜形貌和磁性的影响

化学镀 Co- Ni- P薄膜镀态下为非晶态结构 ,表面较为平整 ;经 30 0℃× 1 h热处理 ,发生了晶化转变 ,表面由“圆锥峰“所构成 ;随加热温度的提高 ,镀层析出了 Co2 P相 ,并发生了由密排六方结构的α- Co向面心立方结构的β- Co的同素异构转变。非晶态 Co- Ni- P薄膜的矫顽力较低 ,矩形比较高 ;薄膜向晶态转变时 ,矫顽力和矩形比皆呈上升趋势 ;50 0℃× 1 h热处理 ,薄膜由α- Co和 Co2 P相构成时 ,且在晶界上偏聚较多磷的影响下 ,矫顽力和矩形比的值达到最高 ;温度继续升高 ,晶粒长大 ,第二相粗化时 ,薄膜的矫顽力和矩形比都减小。化学镀 Co- Ni- P薄膜具有优秀的高密度垂直记录特性。     

非晶态合金Co-Mn-B的电荷转移及其催化性质的DFT研究

为深入了解非晶态合金Co-Mn-B的电子及其催化性能,利用密度泛函理论(DFT)方法,在B3LYP/Lan12dz水平下,将原子簇Co2MnB2的十余种可能构型分别在二、四重态下进行全参数优化计算和频率验证,最后获得两种类型的稳定构型(三角双锥型和变形四方锥型),其中三角双锥构型均是以金属原子为两锥、一金属原子和双B原子位于三角平面。对这些稳定构型的电荷转移及其催化活性进行研究分析,结果表明:原子簇Co2MnB2稳定构型中电子主要由Mn原子向B原子转移,Mn原子的引入起到调变B原子的电子流向作用。金属Co、Mn原子在二、四重态下对HOMO、LUMO轨道的贡献大小不一样;Mn原子的饱和轨道比Co原子更富电子。原子簇Co2MnB2因空轨道易于接受反应物的电子而具有良好的催化性能;构型4(2)具有较好的催化加氢、固氮活性。     

团簇Co4P的自旋布居数及磁学性质研究

以团簇Co4P作为非晶态合金Co-P体系的局域结构,对其进行全参数优化计算,最终得到6种优化构型.通过对团簇Co4P 6种优化构型的Mulliken自旋布居数(包括团簇原子各轨道自旋布居数、团簇轨道自旋布居数及团簇原子自旋布居数)进行分析,对团簇Co4P各优化构型的成单电子进行研究,发现Co原子的d轨道成单电子数最多;...     

代铬镀层--Ni-W、Ni-W-B非晶态合金镀层性能研究

通过在浓硝酸、ω=5％NaCl溶液c=1mol/L H2SO4溶液中的浸渍试验,研究了不同基体上的Ni-W非晶态合金镀层的耐蚀性;通过测定在ω=5％ NaCl溶液及c=1mol／1．的HNO3溶液、H2SO4溶液、HCl溶液中的阳极极化曲线,研究了Ni-W非晶态合金镀层薄膜本身的耐蚀性;采用线性极化方法对Ni—W—B非晶态合金镀层在u=5％ Na—Cl溶液、c=1mol／L H2SO4溶液及HNO3溶液中的腐蚀速度进行了测定,并测定了以上2种非晶态合金镀层的硬度与耐磨性.结果表明．非晶态的Ni—W、Ni-W-B镀层比晶态镀层的耐腐蚀性能要好．而Ni—W—B非晶态合金镀层比Ni—W非晶态合金镀层的耐蚀性能又明显提高;经热处理后,Ni—W—B非晶态镀层的硬度值明显高于Ni—W非晶态镀层,耐磨性能都提高了1倍以上Ni—W、Ni—W—B非晶态镀层极有望成为一种比较好的代铬镀层。     

甲醛在Fe、Co、Ni单掺杂高岭土(001)面的吸附研究

采用基于密度泛函理论(DFT)的第一性原理平面波赝势方法,对Fe、Co、Ni单原子取代Al的高岭土体系(001)面和吸附方式下的体系进行了结构优化,计算并分析了最佳吸附方式下的能量、电荷密度及各原子不同轨道态密度的变化性质。结果表明,Fe、Co、Ni单掺杂高岭土体系对甲醛的吸附均为物理吸附,在吸附过程中HK1801的吸附最为稳定吸附方式,且通过高岭土的-OH作用,使得甲醛的C=O键得到了活化,且吸附体系的稳定性依次为Ni-高岭土体系Fe-高岭土体系Co-高岭土体系。     

玻璃纤维化学镀Ni-Co-Fe-P合金工艺的研究

在玻璃纤维表面化学镀Ni-Co-Fe-P合金,用扫描电镜、能谱仪和X射线衍射仪对其进行了表征.研究了Ni-Co-Fe-P化学镀液中Fe2 /(Ni2 Co2 Fe2 )摩尔比和镀液pH值对化学沉积镀速、镀层成分以及镀层电阻率等影响.镀层在镀态时为非晶结构,镀层Ni61.3Co19.2Fe9.1P10.4的晶化过程为:非晶态→Ni→Ni Ni5P2→Ni Ni3P FeNi3.     

《化学世界》2003年(第44卷)1～12期索引

题　目期　页无机化学新型纳米固载杂多酸盐催化剂的制备与应用 13以硫铁矿烧渣为原料氯酸钠氧化法制备 PFS的研究15煤矸石合成 Na X分子筛的研究 18硫酸软骨素 A对草酸钙晶体生长和聚集的影响2 5 9电化学法制备金属 Co- P纳米粒子 2 6 3碱石灰法从铌钽矿富锆尾矿制备氧氯化锆 2 6 6水基液压介质多功能添加剂的研制 2 6 9从硫铁矿矿渣中制备聚合硫酸铁 2 72七水硫酸锌 (湿法 )生产中 p H值的控制 2 75Ni- Co- B非晶态合金电子性质的理论研究 3115气相燃烧合成纳米 Si O2 颗粒的工艺条件研究 3119DMSO对 CTAB胶束形成影响的实验研究…     

化学镀Co-Ni-P合金薄膜化学成分的考察

考察了影响化学镀Ｃｏ－Ｎｉ－Ｐ合金薄膜化学成分的因素,镀液中ｃｃｏ＾２＋／（ｃｏ＾２＋ｃＮｉ＾２＋）的比值越高和总金属离子浓度越低,薄膜的钴含量越高,镍和磷的含量越低。较高的ｐＨ值和较厚的薄膜会提高薄膜的钴含量,降低镍含量,磷元素倾向于偏聚在晶界上。     

Catalytic behavior of carbon supported Ni-B, Co-B and Co-Ni-B in hydrogen generation by hydrolysis of KBH4

Activated carbon (AC) supported Ni-B, Co-B, and Co-Ni-B catalysts with different Co/Ni mass ratios were synthesized by impregnation of commercial activated carbon with the solution of cobalt and/or nickel salt, and then reduction of metal salts with sodium borohydride at room temperature. Structural properties and morphology of the catalysts were studied using inductively coupled plasma (ICP), XRD and SEM techniques. The B content of the catalyst is less than that required for stoichiometric alloy formation, which indicates the simultaneous presence of the Co and/or Ni metal along with Co-B and/or Ni-B alloy on the surface of activated carbon. The catalytic activity of the catalysts has been tested by measuring the hydrogen generation rate during the hydrolysis of potassium borohydride in basic medium. The results show that Co-B/AC exhibits the highest activity among Ni-B/AC, Co-B/AC and Co-Ni-B/AC catalysts investigated. For supported bimetallic boride catalysts, the catalytic activity increases with Co/Ni mass ratio. The effects of reaction parameters, such as KBH₄ concentration, NaOH concentration, and reaction temperature, on the reaction were also surveyed.     

Catalytic properties of Ni–B and Ni–P ultrafine materials

The ultrafine Ni–B and Ni–P amorphous alloy catalysts were prepared by the chemical reduction method. The catalysts were characterized with respect to ICP‐AES, XRD, nitrogen sorption, DSC, SEM, TEM and XPS. Nitrobenzene hydrogenation was used to compare their hydrogenation abilities. The different metalloids of boron and phosphorus bound to the nickel metal for the Ni–B and Ni–P catalysts result in the distinct different surface area, amorphous structure and hydrogenation activity of the catalysts. Ni–B had a larger surface area than Ni–P. The specific activity per surface area of Ni–P was greater than that of Ni–B. The different activities between the Ni–P and Ni–B can be attributed to the difference of the electron density on the nickel metal; boron donates electrons to the nickel metal and phosphorus accepts electrons from the nickel metal. The catalysts were easier to oxidize when they were exposed to air. This would result in the lower activity. However, the activity could be recovered in the reaction process due to the presence of hydrogen in the reaction system. © 2000 Society of Chemical Industry     

Electroseparation of cobalt and nickel from a simulated wastewater

A study of the electrodeposition at sheet electrodes was carried out under potentiostatic control for solutions containing either 0.1 m Co(ii) or 0.1 m Ni(ii) and a 1:1 mixture of both 0.1 m Co(ii) and 0.1 m Ni(ii). From the linear sweep voltammetry of solutions containing only either Co(ii) or Ni(ii), a potential region in which cobalt would be expected to be electrodeposited without the simultaneous electrodeposition of nickel was identified and a theoretical deposit composition against potential plot was constructed. Deposition from a 1:1 Ni(ii): Co(ii) mixture at the optimum potential for separation produced a 90% cobalt /10% Ni alloy. Long term, potentio-selective extraction from a 1:1 Ni(ii): Co(ii) mixture showed that when the stainless steel cathode was predeposited with pure cobalt, the cobalt level in the solution could be reduced to less than 5% of its original value whilst leaving the Ni(ii) at 85% of its original value.     

Electrolytic oxygen evolution on Ni-Co-P alloys

Electrolytically obtained Ni–Co–P alloys exhibit amorphous structure. On heating these alloys to 773 K crystalline nickel and cobalt phosphide phases, and also nickel crystallites, are formed. After cathode-anode polarization of the amorphous and crystalline Ni–Co–P alloys in 5m KOH for 18 h, oxygen-cobalt compounds together with crystalline or amorphous nickel phosphides appear on the electrode surface. The evolution of oxygen from 5m KOH was studied on Ni–Co–P alloys prepared in this way. The Tafel parameters were determined and it was ascertained that the values of directional coefficients of the Tafel lines are comparable with those obtained for spinel NiCo₂O₄ oxides, while calculated values of the exchange currents for the oxygen evolution reaction are dependent on the chemical composition of the alloy. The rate of electrolytic oxygen evolution is virtually identical for amorphous and crystalline Ni–Co–P alloys of the same chemical composition. The highest rate of oxygen evolution was found for the alloy containing 15–20% Ni, 66–73% Co and 12–14% P.     

Ni-Co-C代硬铬镀层的制备及性能研究(Ⅱ):镀层性能研究

对比所开发的Ni-Co-C代硬铬镀层与商业镍、钴基代硬铬镀层的性能,探究其实际应用价值。由能谱分析及光电子能谱仪测试结果得知,镀层为镍、钴、碳三元合金,且三种元素在镀层中的存在价态均为零价,镍在镀层中主要以Ni和NiCo的形式存在,钴在镀层中主要以Co Ni的形式存在,碳在镀层中主要以C和C/Ni的形式存在,结合X-射线衍射仪测试结果知镀层为部分非晶态、部分金属间化合物的结构。在优化的Ni-Co-C基础镀液及工艺条件下得到的Ni-Co-C代硬铬镀层的硬度较大,在650~750 HV50之间,且Ni-Co-C代硬铬镀层的沉积速度要明显大于商用代硬铬镀层。     

Glucose hydrogenation on Co–B amorphous alloy catalysts and the promoting effect of metal additives

Two kinds of ultrafine Co–B amorphous alloy catalysts, denoted as P‐1 Co–B and P‐2W Co–B, were prepared by chemical reduction with borohydride in aqueous or 50% (v/v) ethanol/water solution, respectively. In comparison with the corresponding Co‐based crystalline catalysts and Ni‐based catalysts, these catalysts exhibited higher activity during the liquid phase glucose hydrogenation, possibly due to the unique amorphous characteristics and the lower d‐band electron density, which was favorable for hydrogen dissociative chemisorption. Addition of Cr‐, Mo‐ or W‐promoters could further increase the conversion of Co–B amorphous catalyst, which was mainly attributed to the dispersion effect of promoters and the adsorption and polarization of carbonyl groups by these promoters. The different effects of W‐ from Cr‐ and Mo‐promoters on the conversion were observed and are discussed. © 2001 Society of Chemical Industry     

从钴镍切削废料中回收有价金属的方法

研究了以钴、镍合金切削废料为原料，通过酸溶、除铁、除铬、钴镍分离等过程，回收有价金属氧化钴、氢氧化镍的工艺条件，通过生产实践，确定了最佳工艺条件及生产工艺，得到的产品质量分别达到国家标准和企业标准。     

Nanocrystalline Ni–Co alloy coatings: electrodeposition using horizontal electrodes and corrosion resistance

Nanocrystalline Ni–Co alloy coatings containing 0–45 wt% Co were electrodeposited using horizontal electrodes in a modified Watts bath. Different techniques including scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, microindentation, and potentiodynamic polarization were used to characterize the alloy coatings. Properties of the alloy coatings were investigated as a function of the cobalt ion concentration (Co²⁺) in the bath. It was observed that the alloy codeposition exhibits anomalous behavior. Co content in the alloy coatings increases with increasing Co²⁺ in the bath and with electrolyte agitation. Morphology and grain size of alloy coatings are greatly affected by Co content. By increasing Co content, surface morphology of the alloy coatings changes from pyramidal to spherical. Microhardness of the alloy coatings increases with increasing Co content mainly due to decreasing grain size that follows the Hall–Petch relation. In addition, Ni–17 wt% Co alloy exhibits better corrosion resistance compared to pure Ni and other Ni–Co alloy coatings. The higher corrosion resistance of Ni–17 wt% Co coating is discussed based on its phase structure, grain size, and preferred orientation.     

Electropolishing of metals in alcoholic solution of sulphuric acid

The potentiodynamic polarization curves of iron, nickel, cobalt, molybdenum, copper and iron-nickel and cobalt-nickel alloys were measured in the polishing solution of 1M H₂SO₄ in CH₃OH. The above mentioned metals and alloys may be divided into three groups: metals and alloys with high dissolution rate in the active state in which the polishing follows immediately behind the active dissolution region (Fe, Co and Ni-Fe and NiCo alloys with a low nickel content), metals and alloys with low passivating current density that become passive at first and the polishing takes place behind the region of localized corrosion (nickel and NiFe and NiCo alloys with a high nickel content) are metals that are polished in the transpassive region (molybdenum).