应力对低合金钢焊接接头相电化学行为的影响

采用微区相电化学测试技术,测量和研究了１６Ｍｎ钢焊接接头上不同热经历区在硝酸盐溶液中的微区相电化学行为（包括自腐蚀电位、自腐蚀电流密度和极化曲线）以及外加载荷（应力）的影响。此外,还分别测量了各区中铁素体和珠光体的电化学行为,尤其是加载状态下的行为。结果表明,加载后各热经历区以及各区中铁素体和珠光体的自腐蚀电位均比未加载前负移,相应的自腐蚀电流密度增大,铁素体和珠光体之间电位差明显减小。加载后各热     

La2O3对Ni-Mo/γ-Al2O3催化剂CO和CO2甲烷化的影响

采用浸渍法制备了一系列Ｎｉ－Ｍｏ－Ｌａ／γ－Ａｌ２Ｏ３催化剂并测定了催化剂的ＣＯ和ＣＯ２甲 化活性采用ＴＥＭ,ＸＰＳ和ＣＯ化学吸附等手段研究了表面性质。结果表明,Ｌａ２Ｏ３的咖入提高了Ｎｉ－Ｍｏ／γ／Ａｌ２Ｏ３催化剂的ＣＯ和ＣＯ２甲烷化活性,增加了催化剂中Ｎｉ的分散度,活性表面积及催化剂表面Ｎｉ原子的浓度,降低了电子结合能。     

ZnO与骨架NiMo物理混合用于丙三醇催化重整-氢解制1,2-丙二醇

以骨架NiMo以及与氧化物物理混合, 考察了其在连续固定床反应器中无外加氢气条件下的丙三醇一锅法重整-氢解制1,2-丙二醇(1,2-PDO)的性能.研究发现, 骨架NiMo自身催化活性高, 但对1,2-PDO的选择性一般.当将其与MgO, SiO₂, Al₂O₃, HZSM-5, TiO₂, ZrO₂或CeO₂机械混合时, 丙三醇转化率和1,2-PDO选择性均发生下降.但当与ZnO物理混合时, 催化活性和选择性均有所提高, 1,2-PDO得率可达52.0%, 优于贵金属催化剂在该一锅法反应中得到的结果.物理混合的ZnO与骨架NiMo之间这种独特的协同作用, 归因于重整过程中产生的CO₂在ZnO上发生化学吸附, 原位增强了ZnO的路易斯酸性.这不仅促进了丙三醇在ZnO上脱水生成中间产物丙酮醇, 也促进了丙酮醇在骨架NiMo上加氢生成1,2-PDO.     

NiMo 催化剂上MoS2 形貌与其DBT 加氢脱硫选择性的关系

制备了两个系列不同镍钼负载量的NiMo 催化剂,并用X 衍射、N2 物理吸附和透射电镜进行了表征。以二苯并噻吩
为模型硫化物,在高压固定床微型反应器上对该NiMo 催化剂的加氢脱硫性能进行了评价,研究了MoS2 形貌与催化剂加氢脱
硫选择性之间的关系。结果表明,镍钼负载量对MoS2 形貌有明显的影响。Mo18Ni4 催化剂(含18% MoO3 和4% NiO)上
MoS2 呈多级层状结构,具有较高的加氢脱硫活性和优异的加氢脱硫选择性。加氢选择性与催化剂上活性组分MoS2 的堆积层
数相关联呈很好的线性关系;堆积层数越多,其加氢选择性也越高。     

植物固体纤维丝在NiMo柴油加氢脱硫催化剂中的应用

通过在氧化铝载体加入微米级植物固体纤维丝扩孔，制备出NiMo柴油加氢脱硫催化剂。采用BET、XRD、SEM、Raman与TEM对制备的载体及催化剂进行表征研究。结果表明，植物固体纤维丝能够在催化剂中构建出部分直筒大孔，NiMo活性组分在催化剂载体上实现了高度分散，活性相MoS₂堆叠层数集中在3-5层，平均MoS₂条长度为4.49 nm。研究了催化剂载体中植物固体纤维丝含量对催化剂活性的影响，并与常规氧化铝载体催化剂进行了对比，高压微反评价结果表明，开发的含有3%（质量分数）植物固体纤维丝NiMo柴油加氢脱硫催化剂比常规NiMo催化剂活性更高，其加氢脱硫活性提高了5%-15%。     

Sn修饰的猝冷骨架NiMo催化剂上的乙二醇液相重整制氢

以猝冷法制备了三元Ni47.8Mo2.2Al50合金,经碱处理活化抽Al及SnCl2修饰,得到了Sn修饰的猝冷骨架Ni-Mo催化剂(RQ SnxNiMo).结果表明,Sn的修饰对催化剂的组成、织构、结构及表面活性位均有显著的影响.将该催化剂应用于乙二醇液相重整反应中,发现Sn的加入使H2选择性大幅度提高.在RQ Sn10NiMo催化剂上,在乙二醇高转化率下,H2选择性达到98.7%,且有效抑制了烷烃的生成.结合催化剂的表征及反应动力学结果,讨论了Sn对猝冷骨架NiMo催化剂的修饰作用.     

CO adsorption on CoMo and NiMo sulfide catalysts: a combined IR and DFT study

Experimental IR spectra of carbon monoxide adsorbed on a series of Mo/Al2O3, CoMo/Al2O3, and NiMo/Al2O3 sulfided catalysts have been compared to ab initio DFT calculations of CO adsorption on CoMo and NiMo model surfaces. This approach allows the main IR features of CO adsorbed on the sulfide phase to be assigned with an uncertainty of 15 cm(-1). On the CoMo system, the band at 2070 cm(-1) is specific of the promotion by Co and is assigned to CO interacting either with a Co atom or with a Mo atom adjacent to a Co atom. On the NiMo system, CO adsorption on Ni centers of the promoted phase leads to a high-wavenumber band at approximately 2120 cm(-1) that strongly overlaps the band at 2110 cm(-1) characteristic of nonpromoted Mo sites. For NiMo and CoMo catalysts, broad shoulders at low wave numbers (below 2060 cm(-1)) are characteristic of Mo centers adjacent to promoter atoms, indicating a partial decoration of the MoS2 edges by the promoter.     

助剂Ni与载体的相互作用及其对NiMo/γ-Al_2O_3催化剂加氢脱硫性能的影响

以γ-Al_2O_3为载体,制备了一系列不同NiO负载量的NiMo/γ-Al_2O_3催化剂,利用XRD、~(27)Al-MAS NMR、Py-FTIR和HRTEM等技术对其进行了表征;在高压微反装置对该系列催化剂的加氢脱硫性能进行了评价,研究了助剂Ni与载体γ-Al_2O_3中不饱和铝间的相互作用及其对催化剂活性相结构形貌和催化活性的影响。结果表明,助剂Ni优先作用于γ-Al_2O_3表面的四配位不饱和铝原子位置;随着NiO负载量的增加,硫化态NiMo/γ-Al_2O_3催化剂中MoS_2活性相的长度变短、堆垛层数增加。Ni的引入能明显提高NiMo/γ-Al_2O_3催化剂的加氢脱硫活性,但其加氢选择性则有所降低。     

磷对预硫化型NiMo/Al2O3催化剂加氢脱硫脱氮性能的影响

利用等体积浸渍法制备了不同磷含量的预硫化型NiMo/Al2O3催化剂,并利用XRD、BET、TPR和HRTEM等分析方法对其进行了表征,研究了磷对其加氢脱硫脱氮性能的影响.结果表明,由于预硫化型NiMo加氢催化剂上活性组分和载体的相互作用较弱,MoS2或Ni-Mo-S相主要以TypeⅡ形式存在,磷通过增加MoS2的堆积...     

Pulse plating effect on microstructure and corrosion properties of Zn–Ni alloy coatings

The influence of pulse plating parameters on the surface morphology, grain size, lattice imperfection and corrosion properties of Zn–Ni alloy has been studied. The coatings were electrodeposited in an alkaline cyanide-free solution. AFM was applied for surface morphology examination, XRD measurements were carried out for phase composition and texture analysis, electron probe microanalysis was used for alloy chemical composition studies, while electrochemical techniques were applied for corrosion performance evaluation. The pulse plated Zn–Ni coatings appeared to consist of the γ-Zn₂₁Ni₅ phase and the composition of the alloy depended on the plating parameters. The grain size, lattice imperfection and homogeneity of grain distribution were established to be the main factors determining corrosion behaviour of the coating. Presented at the 4th Baltic Conference on Electrochemistry, Greifswald, March 13–16, 2005     

纳米晶镍—钼合金电沉积层的结构与性能

通过控电流沉积制备出纳米晶镍钼合金沉积层,沉积层的ＸＲＤ、ＸＰＳ结果表明,纳米晶镍钼合金沉积层存在较大的晶格畸变,其微晶尺寸为１７ｎｍ,纳米合金各元素的结合能发生了不同程度的位移．在３０％的ＫＯＨ溶液中纳米晶镍钼合金电极对析氢反应表现出较高的电催化活性．电化学交流阻抗谱表明,析氢过程按ＶｏｌｍｅｒＨｅｙｒｏｖｓｋｙ机理进行．     

Evaluation of corrosion behaviour of selected metallic samples by electrochemical noise measurements

Electrochemical noise (EN) denotes spontaneous fluctuations in potential and current originating from the corrosion processes. In this work, EN was measured for three model metallic materials of known corrosion properties: Al, Fe and Fe30Al. Corrosion behaviour was assessed in neutral, acidic or alkaline solutions containing 4 wt% NaCl. Correlation between the electrochemical noise and corrosion intensity was established on the basis of appropriate treatment of the recorded numerical data and ex situ examination of the specimen surface. The parameter, referred to as EN resistance, allowed relatively simple and rapid evaluation of the corrosion behaviour of the investigated metallic materials.     

Corrosion behaviour of soldered joints of magnesium alloys and dissimilar materials

In the last decade magnesium based materials have been used in many industrial applications. Problems arise from joining technologies and the corrosion behaviour of joined parts. The present study shows results of a new flux free soldering technology and the study of the corrosion properties of these soldered samples. Joints have been obtained by soldering of magnesium alloy AZ31 samples among each other or to aluminum alloy AlMgSi1 as well as to unalloyed, low-carbon steel. Different corrosion protection layers have been applied by thermal spraying. The corrosive potential of different soldered samples has been examined using current density-potential measurements. The corrosion behaviour of coated samples has been studied by salt spray testing in comparison to uncoated samples.     

机械化学法制备的Al/Ce复合氧化物负载NiMo催化剂的加氢脱硫活性(英文)

将Al和/或Ce的硝酸盐与NH_4HCO_3球磨混合,采用机械化学法制备了Al_2O_3-CeO_2载体(其中Ce含量为1-10 wt%),再以杂多钼酸盐(NH_4)_4NiMo_6O_(24)为活性金属Ni和Mo的前驱体,通过浸渍法制备NiMo_6/Al_2O_3-CeO_2催化剂,并将其用于1-苯并噻吩(BT)的加氢脱硫(HDS)反应中.运用化学分析、X射线衍射、N_2吸附-脱附法、H_2程序升温还原、NH_3程序升温脱附和X射线光电子能谱对催化剂的物化性质进行了表征.结果表明,催化剂的酸性随着载体中Ce含量的增加而下降.Ce修饰的Al_2O_3载体表面的NiS/MoS原子比下降了2倍.NiMo_6/Al_2O_3催化剂表现出最高的HDS活性(以单位重量催化剂计),其酸性和表面MoO_xS_y物种的浓度(Mo~(5+)浓度)也最高;当催化剂中Ce含量逐渐增加到10 wt%以上时,其活性逐渐将为0.与浸渍法制得的参比催化剂相比,前驱体和催化剂组成相同的情况下,采用机械化学法制得的所有催化剂活性明显提高.     

On the surface coverage of alumina by molybdenum-oxide in nickel - and cobalt-promoted MoOx/Al2O3 catalysts

The chemisorption of CO₂ has been studied on alumina-supported Co-and Ni-promoted molybdenum-oxide (CoMo, NiMo) and, besides those, on monometallic Co and Ni. Chemisorbed amounts on the monometallic samples were equal to that on the alumina support. XPS measurements were performed with the NiMo and Ni samples. The amounts of surface Mo-and Al-ions were calculated. It could be established that molybdenum oxide forms a near to monomolecular layer on the Co-and Ni-promoted molybdena-alumina samples.     

多级孔NiMo负载TS-1分子筛催化剂的制备及其加氢脱硫性能

钛硅(TS-1)分子筛的微孔孔道严重限制了其在复杂分子催化转化中的应用,为了克服这一问题,通过酸洗脱、碱刻蚀及二者相结合的方法制备了多级孔 TS-1 分子筛,并采用等体积共浸渍法制备了相应的 NiMo 负载型催化剂;使用 X 射线衍射(XRD)、N₂吸附-脱附、吡啶吸附红外光谱(Py-FTIR)、氢气程序升温还原(H₂-TPR)、X射线光电子能谱(XPS)和高分辨透射电子显微镜(HR-TEM)等方法对多级孔TS-1分子筛的理化性质进行了表征;以二苯并噻吩(DBT)为探针对催化剂的加氢脱硫(HDS)性能进行了评价。结果表明,和常规TS-1分子筛相比,多级孔TS-1分子筛保持了MFI拓扑结构,比表面积增大且具有介孔结构,分子筛表面形成了适量的Brønsted酸中心;相应催化剂上活性金属与载体间相互作用得以改善,MoS₂片晶长度和堆垛层数适宜,形成了更多的 NiMoS活性相;催化剂活性和选择性均有所提升,尤其是酸洗脱获得的 NiMo/AT-TS-1催化剂的活性相较未经处理的NiMo/TS-1催化剂提升了1.2倍,直接脱硫(DDS)路径选择性提升了22%。     

Relationships between microstructure and pitting corrosion of ADI in sodium chloride solution

Austempered ductile iron (ADI) has complex microstructure containing a multiphase matrix (called ‘ausferrite’), graphite spheres and oxide inclusions. The corrosion resistance of ADI is related to its microstructure which is determined by heat treatment parameters (like austempering temperature, austempering time, austenitising temperature and austenitising time). In the present paper, the electrochemical behaviour and corrosion resistance of ADI have been investigated by means of the electrochemical microcell technique and classical electrochemical measurements in sodium chloride solution. Particular attention has been paid to the influence of austempering temperature on the microstructure and pitting corrosion. It has been shown that ADI austempered at 430 °C has upper ausferritic microstructure and reveals a better corrosion resistance in sodium chloride solution than ADI austempered at 280 °C. Moreover, the corrosion resistance increases as the volume fracture of ferrite increases and the carbon content of austenite decreases. The good corrosion behaviour of ADI austempered at 430 °C was also related to the good coarsening of the austenite grains and broad ferrite needles (less ferrite/austenite interfaces). It has been demonstrated that silicon is the alloying element hindering the anodic dissolution of the alloy.     

含钨杂多酸对钢铁腐蚀行为的影响(英)

采用失重法研究了含钨杂多酸在ＮａＣｌ 溶液中对钢铁腐蚀行为的影响．实验结果表明所研究的杂多化合物对钢铁均具有一定的缓蚀作用．但杂多酸盐特别是缺位型杂多酸盐的缓蚀效果较好．     

NiMo/Al_2O_3-USY催化剂上中低温煤焦油加氢裂化性能研究

采用等体积浸渍法制得一系列NiMo/Al_2O_3-USY催化剂,在200 mL固定床上考察了不同金属负载量对其中低煤焦油加氢裂化催化性能的影响,进一步用NH_4F溶液改性USY以提高催化剂的脱硫性能,并结合XRD、氮气吸附-脱附、XPS、HR-TEM、H_2-TPR和NH_3-TPD等手段对催化剂进行了表征分析。结果表明,NiM o/Al_2O_3-USY催化剂适宜的M oO_3负载量为15%(质量分数);当MoO_3含量超过15%后,MoS_2活性相在载体上团聚,硫化程度趋于稳定,强酸酸量和孔径减少,增加金属负载量对煤焦油加氢裂化转化率影响较小。NH_4F改性USY可增大NiM o/Al_2O_3-USY催化剂的孔径,有利于提高煤焦油加氢裂化转化率。表面强酸酸量减少后,产品中的硫含量明显增加,说明强酸酸量是影响产物硫含量的关键因素。当NH_4F浓度为0.6 mol/L时,NH_4F改性USY制得的NM 0.6催化剂上煤焦油加氢裂化的转化率为87.65%,产品汽油馏分(≤180℃)硫含量为5.96 mg/kg,柴油馏分(180-320℃)硫含量为34.98 mg/kg。     

Synthesis of Holey Graphitic Carbon Nitride with Highly Enhanced Photocatalytic Reduction Activity via Melamine-cyanuric Acid Precursor Route

In this work, holey graphitic carbon nitride(HCN) was prepared by one-step thermal polymerization of hydrothermal product of melamine and then loaded with Ni/MoO₂(NiMo) cocatalyst obtained by NaBH₄ reduction process. The obtained material was used for photocatalytic production of H₂ from water reduction and H₂O₂ production from O₂ reduction. The best photocatalyst(1% NiMo/HCN) exhibited a H₂ evolution rate of 8.08 μmol/h while no H₂ was detected over 1% NiMo-modifed bulk g-C₃N₄(BCN) under visible light illumination. Moreover, this rate is 1.7 times higher than that of 1% Pt-modified HCN. The 1% NiMo/HCN catalyst also exhibited the highest H₂O₂ production activity with a value of 6.13 μmol/h. Such enhancement was ascribed to the efficient charge carrier separation and migration, which were promoted by the large specific surface area and pore volume of HCN and the synergy between MoO₂ and Ni. The proposed method to obtain HCN is expected to open up new ways in development of highly-active HCN-based photocatalysts for photocatalytic reduction reactions.