共查询到20条相似文献,搜索用时 640 毫秒
1.
2.
(Pb_(0.88)Nd(0.10))(Ti_(0.92)In_(0.06)Mn_(0.2))O_3超细陶瓷粉末的制备与研究杨昆山,陈种菊,陈坚业,张惊涛(四川联合大学化学系,成都,610064)关键词超细粉,共沉淀,制备掺In2O3、Nd2O3和MnO?.. 相似文献
3.
利用固相反应合成了Eu_(0.5)RE_(0.5)Fe_(0.5)Mn_(0.5)O_3(RE=La,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Y)等化合物。测量了其XRD谱及~(57)FeMssbauer谱.实验发现,随着RE原子序数的增加,样品的晶胞体积减小,Fe在化合物中处于Fe~(3+)的高自旋状态,~(57)Fe的四极裂矩与样品的畸变参数D成线性关系。 相似文献
4.
微波辐照下(Bi_2O_3)_(0.8)(La_2O_3)_(0.2)固熔体对甲烷氧化偶联的催化行为陈长林,洪品杰,戴树珊,阚家德(云南大学化学系,昆明,650091)关键词微波,甲烷氧化偶联,(Bi_2O_3)_(0.8)(La_2O_3)_(0.2)甲烷氧化... 相似文献
5.
6.
利用固相反应合成了稀土取代的复合氧化物Eu_(0.5)RE_(0.5)Fe_(0.5)Mn_(0.5)O_3(RE=La,Pr,Nd,Sm,Gd,Tb,Dy,Ho,Er,Tm,Yb).测量了这些化合物的XRD和XPS谱。在XPS研究中发现,稀土取代而使稀土元素本身的结合能相对于其倍半氧化物中的有所降低;在取代的复合氧化物中,随着RE离子半径的减小,Fe、Mn的结合能随之增加。 相似文献
7.
La,Ce,Nd和Pr对RE(NiCoMnTi)5贮氢合金电化学性能的作用机理 总被引:3,自引:0,他引:3
系统地研究了稀土(RE=La1-x-y-zCexNdyPrz)对贮氢合金RE(NiCoMnTi)5电化学性能的影响。结果表明,La、Ce、Nd和Pr比例对合金性能有显著影响,RE=La0.4Ce0.1Nd0.2Pr0.3时,对应合金具有最高放电容量,为290mAh/g,并有较好的循环寿命。从原子结构和性质角度分析了La,Ce,Nd和Pr作用的机理。 相似文献
8.
研究了镍部分取代AB2型CeMnAl金属间化合物B侧Mn,Al形成的化学计量比合金的结构和电化学性能。XRD分析,SEM形貌观察和电化学性能测试结果表明:镍的部分取代使合金发生了相变化,形成了新相,CeMn1-x,A11-x,Ni2x(x=0.0,0.25,0.50和0.75)合金电极的电化学活性得到很大提高,298K时的放电容量从x=0时的17.93mAh·g^-1提高到x=0.75时的118.3mAh·g^-1,328K时的放电容量从x=0时的68.42mAh·g^-1提高到x=0.75时的216.1mAh·g^-1。合金的电化学P-C-T曲线表明:无Ni的CeMnAl合金几乎没有平衡氢压平台,随M取代量的增加,合金的平衡氢压平台斜率变小,宽度增大。 相似文献
9.
在22-60℃范围内研究了贮氢合金MnNi3.55Co0.75Mn0.44Al0.3(Mn为富铈混合稀土金属)在a和α+β相区恒温吸氢动力学过程。研究结果表明,合金在α相区吸氢受化学反应控速,动力学规律不受氢初压的影响,在整个α+β相区吸氢过程中,受氢在合金氢物中的扩散控速,得到相应的速率方程和表观活化能。 相似文献
10.
Syntheses,StructuresandPropertiesofSome NewCompositionPerovskiteCompounds:Sr_(0.6)Bi_(0.4)FeO_(2.7),Sr_(1-x)Bi_xFeO_(3-y) and Ba... 相似文献
11.
12.
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. 相似文献
13.
R. Ramanauskas L. Gudavičiūtė A. Kaliničenko R. Juškėnas 《Journal of Solid State Electrochemistry》2005,9(12):900-908
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 相似文献
14.
Hybrid microspheres of poly(methyl acrylate‐co‐divinylbenzene) (PMADVB) with a thin and porous nickel–phosphorus (Ni–P) alloy layer were prepared via suspension polymerization and electroless nickel plating. The characterization of pristine and nickel‐coated microspheres was carried out with a differential scanning calorimeter and a scanning electron spectroscope equipped with an energy‐dispersive system. The glass‐transition range of Ni–P‐coated PMADVB was broadened and extended in the higher temperature direction. This effect allowed the PMADVB network to embrace more diversified energy states of the segment motion, this being a desired feature for damping sound waves. The low‐frequency (100–1000‐Hz) sound absorption behavior of the microspheres was tested with a sound attenuation kit. Besides the testing of their low‐frequency damping performance, an investigation into the ultrasonic‐wave (~35 kHz) absorption feature of the microspheres was conducted through chemical means; that is, the attenuation to the ultrasonic wave with respect to the unprotective situation was assessed through the chemisorption extent of copper ions on a biomass adsorbent. The Ni–P deposition layer was found to augment the damping capacity of the polymer network. The alloy layer was determined to cause an expansion of the glass‐transition range of PMADVB and its wave‐scattering capability because this layer was made up of submicrometer metallic grains. In this work, the particulars of the metal–polymer interactions were associated with a core–shell structure. The metal outer layer was thought to create a spherical temperature field inside the PMADVB network, and concerted motions of the polymer segments resulted. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2710–2723, 2004 相似文献
15.
When Cu(110), Ni(l 10), Ag(110) surfaces are exposed to O2 at room temperature, one dimensional metal-oxygen strings grow in the < 001 > direction of the (110) surfaces. A similar phenomenon occurs in the adsorption of H2 on Ni( 110) surface at room temperature, where the one dimensional strings grow along the < 110 > direction. These phenomena are undoubtedly different from the adsorption induced reconstruction but are explained by the chemical reconstruction involving the formation of quasi-compounds and their self-ordering on the metal surfaces. The chemical reconstruction is indispensablly important to understand the structure and catalysis of alloy and bimetallic surfaces. Pt0.25Rh0.75(100) alloy surface being active for the reaction of NO with H2 is an interesting example. When the Pt-Rh(100) alloy surface is exposed to NO or O2 at arround 500 K, a p(3 × 1) ordered Rh-O over-layer is obtained on a Pt-enriched 2nd layer by the chemical reconstruction. Ordering of Rh-0 in the p(3 × 1) structure on the Pt(100) surface was reproduced by heating a Rh/Pt(100) bimetallic surface in O2, and the chemical reconstruction making the p(3 × 1) Rh-O overlayer on a Pt enriched 2nd layer was also proved by heating a Pt/Rh(100) bimetallic surface in O2 or NO. The activation mechanism of the Pt-Rh alloy and the Pt/Rh bimetallic surfaces by the chemical reconstruction was evidently shown by using a Pt deposited Rh(100), Pt/Rh(100), surface. That is, the Pt/Rh(100) is not so active for the reaction of NO with H2, but the reconstructed p(3 × 1)Rh-O/Pt-layer/Rh(100) surface is very active for the reaction. Therefore, it was concluded that the chemical reconstruction of the Pt-Rh catalyst makes the active surface which is composed of Rh-O and a Pt layer. 相似文献
16.
Coaxial metal and magnetic alloy nanotubes in polycarbonate templates by electroless deposition 总被引:1,自引:0,他引:1
James F. Rohan Declan P. Casey Bernadette M. Ahern Fernando M.F. Rhen Saibal Roy David Fleming Simon E. Lawrence 《Electrochemistry communications》2008,10(9):1419-1422
We present a novel technique for the preparation of coaxial metal and magnetic alloy nanotubes, which is demonstrated for the coaxial nanotubes of Ni/Co and Ni/CoNiFe alloys deposited in activated polycarbonate templates using electroless plating. For each metal or alloy the tube wall thickness was controlled to be less than 100 nm. The process involved two consecutive deposition steps from hypophosphite and/or borane reducing agent based electroless plating solutions. We further characterise the magnetic properties of the ternary magnetic alloy films and coaxial nanotubes. The coaxial tubes show homogenous wall thickness and composition, which is delineated from the magnetic measurements. 相似文献
17.
18.
氟化物体系三价铬镀铬工艺的研究 总被引:2,自引:0,他引:2
采用恒电位法在氟化物体系中镀铬,以铅银合金为阳极,20号不锈钢片为阴极,探讨了电流密度、温度、pH值、时间等因素对电镀效率的影响.研究表明:在氟化物体系中,镀液温度为30-40℃,pH=1.65,电流密度=30 A/dm2,反应时间在15 m in时,即能得到细致光亮结合力牢固的金属铬镀层,并且电镀效率达到29.46%. 相似文献
19.
Z. -L. Wang Y. -X. Yang J. -B. Zhang H. Zhu Y. -R. Chen 《Russian Journal of Electrochemistry》2006,42(1):22-26
The electroplating of bright Zn-Ni alloy process using HEDP as coordinating agent, ZNP as additive agent is studied. The effect
of coordinating agent, chloride content, [Zn2+]/[Ni2+], cathode current density, temperature, and supplementary coordinating agent on Ni content is investigated; composition and
physical phase of alloy plating layer, brightness of plating layer, and stability of plating solution are comprehensive considered;
and also, the optimum composition of plating solution for bright Zn-Ni alloy electroplating and technological condition is
determined; finally, deposition mechanism is discussed.
Published in Russian in Elektrokhimiya, 2006, Vol. 42, No. 1, pp. 25–30.
The text was submitted by the authors in English. 相似文献
20.
通过化学镀和电化学镀的方法制备了一种Ni(OH)2电化学活性材料修饰三聚氰胺泡沫(MF)可压缩骨架的超级电容器电极材料MF/Ni(OH)2。MF/Ni(OH)2可压缩电极材料表现出最佳的电容性能,例如循环稳定性(即使在40 mA/cm-3的电流密度下经过2000次充放电循环后,可压缩电极仍能保持90.63%的初始电容)和可压缩稳定性(即使在压缩率为50%时,仍具有97.88%的电容保持率)。层状可压缩超级电容器由MF/Ni(OH)2弹性材料作为阳极,镍/碳(Ni/C)为阴极以及实验室中常用的滤纸作隔膜材料组成。这种超级电容器装置在不同的压缩下表现出良好的电化学性能和优异的压缩稳定性。最后,使用可压缩的超级电容器来点亮LED灯,以展示其在柔性电子设备中的应用。这些优化的电化学和机械性能表明MF/Ni(OH)2可作为可压缩超级电容器的应用中的候选电极。 相似文献