Senlin WANG
材料科学技术（英文）
Electroless Ni-Fe-P alloys in an alkaline bath were plated. The effects of deposition parameters on the plating rate and the coating composition were examined. The weight loss test and the anodic polarization measurement of the deposits in 3.5 wt pct NaCl solution (pH7.0) showed that the deposits with the mole ratio of NiSO¬4/FeSO¬4 being 0.07:0.03, pH8.0 and 7.5 possess better corrosion resistance than that of the other deposits and the Ni-Fe-P deposits did not form passive films in this environment. In 5.0 wt pct NaOH solution, the Ni-Fe-P deposits have better corrosion resistance and formed passive films.
关键词:
Nickel
,
null
,
null
,
null
Supawan Vichaphund Duangduen Atong
材料科学技术（英文）
This work reports two preparation methods of Ni-Al2O3 composite to be used as a hydrogen separation membrane. The first method was powder impregnation while the second method was soaking-drying-firing or bulk impregnation. In the first method, the 10 wt pct Nickel (II) nitrate hexahydrate solution was mixed with Al2O3 powder. The mixed powders were dried at 100°C and uniaxially pressed into a disk shape at 7 MPa. The densification of composite membranes was accomplished by pressureless sintered at 900-1300°C. For the second preparation method, the Al2O3 disk support was prepared firstly by uniaxially pressing Al2O3 powder at 7 MPa and then sintered at 1000-1200°C for 2 h. After that, the Al2O3 support was soaked into 10 wt pct Ni solution, dried at 100°C and calcined at 900°C for 2 h. The soaking-drying-firing sequence was repeated ten times to finally obtain the Ni-Al2O3 membranes. After preparation process, the membranes fabricated from these two methods were reduced at 910°C for 2 h in hydrogen atmosphere. The effect of the preparation method on properties of membranes in terms of density, porosity, phase and microstructure are discussed.
关键词:
Composite membrane
,
hydrogen separation
,
Nickel
,
Alumina
Feng XIAO
,
Liang FANG
,
Kiyoshi NOGI
材料科学技术（英文）
Surface tension of molten Ni and Ni-Co (5 and 10 mass fraction) alloys was measured at the temperature range of 1773~1873 K using an improved sessile drop method with an alumina substrate in an Ar+3%H2 atmosphere. The error of the data obtained was analyzed. The surface tension of molten Ni and Ni-Co (5 and 10 mass fraction) alloys decreases with increasing temperature. The influence of Co on the surface tension of Ni-Co alloys is little in the studied Co concentration range.
关键词:
Nickel
,
null
,
null
,
null
Ximiao PAN
,
Zhanpeng JIN
材料科学技术（英文）
The phase equilibrium relations of the ternary Ni-Cr-Zr system at 900°C have been investigated by means of diffusion triple and electron probe microanalysis (EMPA) techniques. A series of tie lines and triangles have been determined, and the corresponding tentative isothermal section is presented based on the current information.
关键词:
Nickel
,
null
,
null
,
null
S.M.Rashwan
,
A.Emam
,
S.M.Abd El-Wahab
,
M.M.Mohamed
材料科学技术（英文）
Anodic dissolution behaviour of Ni in mono-, di- and trichloroacetic acids has been investigated by measuring current densities of Ni electrode (versus SCE) at different potentials. Effects of acid concentration, pH, scan rate and additive inhibitor on the potential were studied and they revealed that there is a considerable shift of potential. Potentiodynamic polarization measurements show that the corrosion rate of Ni in chloroacetic acid solutions increases by increasing the previous factors. However, by adding inhibitor, it decreases.
关键词:
Corrosion
,
null
,
null
,
null
Feng Yang
,
Wenhuai Tian
,
Chuanchao Feng
,
Baosheng Wang
金属学报(英文版)
doi:10.1016/S1006-7191(08)60112-X
Two types of electroformed nickel liners of shaped charges were prepared by electroforming technique. X-ray diffraction (XRD), transmission electron microscopy (TEM), electron backscattering diffraction (EBSD) technique and high resolution electron microscopy (HREM) have been employed to investigate the crystal defects formed in electroformed nickel liners of shaped charges. The result shows that (100) fiber texture which is parallel to the grown direction exists in the electroformed nickel prepared by using direct current electroforming without any additives, and (111) fiber texture exists in the electroformed nickel prepared by using direct current electroforming with additives. The deposits prepared by using direct current electroforming possess columnar grain with an average grain size of 30 μm in width and 170 μm in length. The deposits prepared with additives are composed of a colony structures with grain size of about 29 nm, and a lot of crystal defects such as twins, antiphase boundaries and stacking faults have been observed in the electroformed nickel.
关键词:
Electroformation
,
null
,
null
,
null
,
null
Květa Jirátová
,
Alla Spojakina
,
Luděk Kalu?a
,
Radostina Palcheva
,
Jana Balabánová
,
Georgi Tyuliev
催化学报
doi:10.1016/S1872-2067(15)61016-6
将Al和/或Ce的硝酸盐与NH4HCO3球磨混合，采用机械化学法制备了Al2O3-CeO2载体(其中Ce含量为1–10 wt%)，再以杂多钼酸盐(NH4)4NiMo6O24为活性金属Ni和Mo的前驱体，通过浸渍法制备NiMo6/Al2O3-CeO2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、N2吸附-脱附法、H2程序升温还原、NH3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Al2O3载体表面的NiS/MoS原子比下降了2倍. NiMo6/Al2O3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MoOxSy物种的浓度(Mo5+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.
关键词:
镍
,
钼
,
氧化铝
,
氧化铈
,
Anderson型杂多钼酸盐
,
1-苯并噻吩
,
加氢脱硫
,
机械化学法
张兴华
,
张琦
,
陈伦刚
,
徐莹
,
王铁军
,
马隆龙
催化学报
doi:10.1016/S1872-2067(12)60733-5
采用化学沉淀法合成了SiO2-ZrO2复合氧化物载体，并以浸渍法制备了Ni/SiO2-ZrO2双功能催化剂，考察了焙烧温度对催化剂结构及其催化愈创木酚加氢脱氧制环己烷性能的影响.结果表明，经500°C焙烧催化剂的加氢脱氧活性最高，在Ni金属中心和SiO2-ZrO2载体材料的协同作用下，愈创木酚转化率为100%，环己烷选择性为96.8%.对催化剂进行N2物理吸附、H2化学吸附、X射线衍射分析、H2程序升温还原、NH3程序升温脱附与Raman光谱等表征后发现，合成的SiO2-ZrO2为无定形的酸碱两性氧化物；经500°C焙烧的催化剂样品的有效比表面积和孔体积均明显增大，表面酸量最多，硝酸镍分解成小颗粒的NiO较易被H2还原，这些特性是该催化剂样品具有高效加氢脱氧活性的原因.
关键词:
镍
,
氧化硅
,
氧化锆
,
焙烧温度
,
愈创木酚
,
加氢脱氧
,
环己烷
谭鹏甲
,
高志华
,
沈朝峰
,
杜亚丽
,
李晓东
,
黄伟
催化学报
doi:10.1016/S1872-2067(14)60171-6
采用表面活性剂辅助共沉淀法制备了Ni-Mg-Al固体碱催化剂并用于CH4-CO2重整反应，探讨了表面活性剂对Ni(111)， Ni(200)晶面的择优取向作用，在800°C下比较了不同表面活性剂制备的催化剂的催化性能，详细考察了CTAB制备的催化剂CB-LDO在不同反应温度下的催化活性和稳定性。采用红外光谱、X射线衍射、程序升温还原、X射线光电子能谱、高分辨透射电镜和程序升温氧化等表征手段分析了催化剂的活性、稳定性和失活原因。结果表明，四丙基氢氧化铵(TPAOH)促进Ni(200)的生长，而聚氧乙烯-聚氧丙烯-聚氧乙烯(P123)、聚乙烯吡咯烷酮(PVP)和十六烷基三甲基溴化铵(CTAB)抑制Ni(200)晶面的生长；Ni(200)的结晶程度对CH4的活化起到关键的作用，催化剂CB-LDO在高温下反应会发生晶型的转化， Ni(200)晶面由于反应过程中生成NiAl2O4尖晶石而得到缓慢释放，使催化剂的活性得以维持较高的水平。
关键词:
表面活性剂
,
共沉淀法
,
镍
,
镁铝氧化物
,
甲烷
,
二氧化碳
,
重整
简思平
,
李映伟
催化学报
doi:10.1016/S1872-2067(15)60940-8
金属有机骨架(MOFs)材料是一种新型的沸石类多孔材料,是由金属离子和有机配体通过配位键键合而成的拓扑结构.相比其他多孔材料,MOFs拥有更高的比表面积、孔隙率以及结构可调控性.在催化方面,MOFs复合材料在多相催化领域已经引起了广泛的研究兴趣.贵金属纳米颗粒是一种在化学、化工、生物和医学等许多领域有着广泛应用的高性能材料.但是,催化反应往往都是发生在纳米颗粒的表面,而位于颗粒内部的金属没能得到利用;从原子经济性的角度来看,以廉价金属作核、贵金属作壳的双金属纳米粒子能有效解决这个问题,而且还能利用双金属之间的协调作用.目前文献中也已经报道了多种非贵金属和贵金属组成的核壳双金属纳米粒子,都展现出了比单纯贵金属更好的催化活性.芳香胺类化合物是一种在工业上非常重要的有机中间体,广泛应用于农药、药物、染料和色素等等.目前,商业化生产的芳香胺化合物都是通过计量的还原剂,如连二硫酸钠、硼氢化钠、水合肼和氨水中的铁、锡、锌等非催化还原相应的芳硝基化合物得到,这样往往会带来严重的环境污染问题.而通过多相催化加氢还原方法来制备芳香胺化合物,不仅能高效催化芳硝基化合物加氢,而且催化剂可以回收利用,大大降低反应对环境的污染.本文综合贵金属原子经济观点和芳硝基类化合物加氢反应催化剂设计,在油胺和三正辛基膦中通过热还原二价的镍和钯,制备出以Ni为核Pd为壳的双金属纳米粒子.通过透射电镜观察,镍钯核壳纳米粒子的粒径约为8-9 nm.选用具有高比表面积和高稳定性的金属有机骨架材料MIL-101作为载体,通过浸渍法首次将镍钯核壳纳米粒子负载在MIL-101上制备出不同Ni:Pd比的Ni@Pd/MIL-101复合材料.利用X射线粉末衍射(XRD)、N2吸附-脱附、红外光谱、透射电子显微镜和X射线能谱对复合材料结构进行了表征.从XRD谱图能看出负载纳米粒子后的MIL-101材料结构依然保持完整,表明催化剂制备过程不会破坏载体结构.红外光谱测试结果表明,负载了镍钯纳米粒子的Ni@Pd/MIL-101复合材料中含有两种C-H键伸缩振动2852和2926 cm-1处两个特征峰,分别对应于-CH2-和-CH3中C-H键的特征吸收峰,可能是残留的油胺,也可能是三正辛基膦在与镍和钯形成配合物时的残留.X射线能谱测试发现,N元素在负载后已不存在,而P元素依旧存在,结合红外光谱可以确认,纳米粒子在负载前后三正辛基膦依然与纳米粒子稳定络合,进而可被MIL-101上未饱和的Cr固定.通过透射电镜可以观察到镍钯核壳纳米粒子高度分散在载体上.将Ni@Pd/MIL-101材料应用于硝基苯催化加氢反应.在30℃,0.1 MPa H2条件下,0.26％ Ni@0.46％Pd/MIL-101催化剂具有最高的加氢活性,其转换频率(TOF)值最高可达375 h-1,是单金属负载钯催化剂的近2倍,展示出非贵金属替代部分贵金属的可行性.在循环使用方面,重复使用5次后的Ni@Pd/MIL-101催化剂依然保持较高的催化活性和选择性.同时考察了底物的兼容性,该催化体系对多种不同基团(包括不饱和基团)取代的硝基苯化合物的催化加氢,大都表现出很高的催化活性和选择性,TOF值最高可达495 h-1.
关键词:
镍
,
钯
,
核壳纳米粒子
,
金属有机骨架
,
芳香硝基类化合物
,
加氢
,
多相催化
