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1.
无电解镀镍磷非晶态合金的近边结构研究   总被引:2,自引:1,他引:2  
用DTA,XRD和EXAFS方法研究无电解镀镍磷合金层结构,其中含P10%(重量百分比)左右的Ni-P合金层是非晶态合金固溶体,Ni,P之间存在共价键作用,Ni-Ni键长0.25nm,Ni-P键长0.28nm经400℃热处理1后的含P10%的Ni-P镀层是Ni3P晶态与Ni-P非晶态的混合物,EXAFS方法给出了镍磷合金层的结构,键长和配位原子情况,体现出EXAFS方法在研究金属结构尤其是非晶态金  相似文献   

2.
掺硅MlNi5系稀土贮氢合金电化学性能   总被引:6,自引:0,他引:6  
对MlNi3.5Co0.75-xSixAl0.2Mn0.55的显微组织结构及电化学性能进行了系统的研究。当x=0.1,0.2时,合金的放电容量较大、活化速度快、大电流放电容量较高、放电电压稳定。X射线分析和扫描电镜观察表明该系合金由LaNi3与La2Ni7两相组成,且随Si含量的提高,非贮氢相LaNi7相增加。  相似文献   

3.
p—Si上电沉积Ni—W—P薄膜的结构与热稳定性   总被引:3,自引:0,他引:3  
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.  相似文献   

4.
研究了富镧混合稀土贮氢合金MINi5及加Sn后对合金的结构、活化性能、吸氢容量和平衡氢压等性能的影响。通过X射线衍射分析进行物相分析,测试了298,313,333K温度下合金的吸、放氢P-C-T曲线。结果表明,MINi5-xSnx合金(x=0~0.4)为六言晶体结构的单相组织。以Sn部分取代Ni改善了MINi5的活化特性,并使平台压力降低、吸、放氢滞后减小。随着Sn含量增加,晶胞体积增大,平衡氢压  相似文献   

5.
活性炭为载体加氢脱氮催化剂的研究   总被引:1,自引:0,他引:1  
Mo/C、Ni/C和Ni-Mo/C催化剂吡啶加氢脱氮研究表明,Mo/C催化剂在Mo含量小于3.65%时,随着Mo含量的增加,脱氮活性增加,其后趋于稳定。Ni/C催化剂也具有加氢脱氮活性,在Ni含量为5%左右达到最大值。Ni-Mo/C催化剂只有在Ni和Mo相互匹配时才具有较高的活性。XPS的研究表明,硫化后Ni-Mo/C催化剂的Mo主要是以MoS2的模型存在的;Ni是以NiS和Ni3S2的混合生存在  相似文献   

6.
在贮氢合金MmNi3.8Co0.5Mn0.4Al0.3(Mm为混合希土)粉末表面分别进行化学镀Cu,Co,Ni,Ni-Co,Ni-Sn,Ni-W。结果表明不同化学镀对合金贮氢性能有很大影响。  相似文献   

7.
Ni—Mo合金复合镀层上的析氢反应   总被引:6,自引:1,他引:6  
马洁  初一鸣 《应用化学》1997,14(1):16-20
用稳态极化曲线及交流阻抗等电化学技术研究了不同沉积条件(沉积温度、沉积时间、沉积电流、镀液组成)所得纳米晶Ni-Mo合金复合镀层上的析氢反应,并用扫描电镜及X光能谱监测了电极表面的形貌及镀层组成,实验结果表明:沉积温度30℃、沉积7200s,较大的沉积电流及含钼镀液对析氢更为有利  相似文献   

8.
改变聚(甲基丙烯酸甲酯-苯乙烯(P(MMA-co-St)中 甲基丙烯酸甲酯的含量(WMMA),通过一步法合成出聚环氧氯丙烷聚氨酯(PU(PECH)/P(MMA-co-St)IPN.DSC、TEM和动态粘弹谱研究结果表明:当P(MMA_co-St)中WMMA大于0.6时,IBN仅有一个Tg;当WMMA小于0.4时,IPN有2个Tg,TEM上出现相区,P(MMA-co-St)深度参数(δ)及δ的氢键作  相似文献   

9.
Ni—Mo—PTFE复合电极的制备及其对甲醇电氧化的催化性能   总被引:4,自引:0,他引:4  
黄令  许书楷 《应用化学》1997,14(4):21-24
在0.22mol/L硫酸镍,0.06mol/L钼酸钠,0.3mol/L柠檬酸钠,30g/LPTFE乳液,0.1g/LFC-400表面活性剂的电解液(pH=9)中,于温度45℃,通以10mA/cm2的电流,在纯Cu片上沉积出Ni-Mo-PTFE复合沉积层,XRD、XPS表征结果表明,该复合沉积层属立方晶系,其点阵型式为面心点阵F,晶胞参数a为0.3573nm,镍钼合金为固溶体结构,其(111)织构度TC(111)为68%,表明该沉积层呈(111)择优取向.沉积层表面的氟以(CF2)n的形式存在,SEM观察结果表明沉积层含有PTFE时表面的粗糙度增大.镍-钼-PTFE复合电沉积过程经历吸附态物种氢氧化镍和钼的氧化物,它们继续捕获电子被还原为镍钼合金,PTFE粒子以包埋的形式沉积于镀层中.循环伏安结果表明该复合电极在NaOH溶液中对甲醇的电氧化具有催化活性.  相似文献   

10.
Ni-Mo合金电沉积层织构及形成机理   总被引:2,自引:0,他引:2  
在组成为:0.22mol/L硫酸镍、0.06mol/L钼酸钠和0.3mol/L柠檬酸钠的溶液,于纯铜片上采用恒电流沉积,所得Ni-Mo合金沉积层经X射线衍射测定,结果表明在温度为25℃~50℃,电流密度为10mA·cm-2~30mA·cm-2范围,Ni-Mo合金沉积层表现为(111)择优取向.循环伏安和电位阶跃实验表明镍钼合金电结晶过程按照连续成核和三维生长方式进行.Ni-Mo合金电沉积过程的电化学交流阻抗谱表明Ni-Mo共沉积过程经历了吸附中间产物步骤,由于吸附态物种氢氧化镍和钼的氧化物将阻化晶粒(111)晶面的生长,从而使镍钼沉积层表现为(111)择优取向.  相似文献   

11.
非晶态Ni-Ce-P合金的共沉积与耐蚀性能   总被引:8,自引:0,他引:8  
刘江  蒋雄  江琳才  朱则善 《电化学》2001,7(3):294-301
采用恒电位沉积、循环状安等方法研究了在水溶液中电沉积稀土合金的可能性 ,首次在含有CeCl3的弱酸性NaH2 PO2 镀液中获得了不同铈含量的Ni Ce P合金镀层 ,XPS、AES、XRD和SEM等实验技术表征了镀层的组成和结构 ,极化电阻和腐蚀电位的测试数据表明此镀层与Ni P无定形合金相比 ,具有更强的耐腐蚀能力 ,同时 ,讨论了沉积条件与镀层耐蚀性能的关系 ,结论是 :镀层中铈含量越高 ,其耐腐蚀性能越好 ,此外还对Ni Ce P的共沉积机理进行了初步探讨 ,指出在所研究的电沉积条件下 ,Ni Ce P合金共沉积可以用“诱导共沉积理论”合理解释  相似文献   

12.
电沉积条件对非晶态Fe-Mo合金结构及表面性质的影响   总被引:3,自引:0,他引:3  
利用XRD、SEM和XPS等手段研究了电解液中x(Mo)(Mo在Mo+Fe中的摩尔分数)、电流密度及温度变化对电沉积非晶态Fe-Mo合金的结构和表面性质的影响.溶液中主要含有FeSO4、Na2MoO4、H3Cit和NaCl,pH值3~5.当x(Mo)大于50%,电流密度高于25mA/cm2,温度低于40℃时有利于形成非晶态结构.合金沉积层的表面呈颗粒状且有微裂纹,表面的化学性质很活泼,容易形成含低价Mo的有色氧化物表面膜.非晶Fe-Mo合金沉积层在3%NaCl溶液中的耐蚀性优于纯铁.  相似文献   

13.
Electroless Zn–Ni–P thin films were deposited on low carbon steel from an alkaline non‐cyanide aqueous electrolyte. The newly developed ternary alloys structure and microstructure investigations were carried out via X‐ray diffraction and SEM. Chemical composition of the coatings was investigated via energy dispersive spectroscopy. Polarization tests were used to study the corrosion properties of the coatings in a 3.5 wt.% NaCl solution. The results confirmed the high corrosion resistance of Zn–Ni–P alloy plated steel sheet. The surface analysis of the thin film samples before and after corrosion was performed by XPS. The incorporation of Zn in Ni–P thin film is proven for all initial samples to be as a mixture of zinc and zinc oxide, while nickel exists in +2 and +3 oxidized states. A passive film of a mixture of oxide and hydroxide of zinc and nickel forms on the surface and prevents the Zn–Ni–P thin films from corrosion. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

14.
Ni–W alloys were electrodeposited onto copper foil from citrate solution. Coatings containing from 11 to 21 at.% W and having 7–52 μm in thickness were obtained. The structure of these alloys was analyzed by X-ray diffraction and by using electron and light microscopy techniques. Alloys with 11 and 15% W are composed of two phases: solid solution of W in fcc Ni and solid solution of Ni in bcc W. An increase in W content in the Ni–W alloys to ca. 18–19% of W resulted in the grain refinement and the transition to amorphous structure. The corrosion behavior of obtained Ni–W and unalloyed Ni coatings was studied in 0.5 M NaCl solution by means of electrochemical impedance spectroscopy, potentiodynamic polarization and light microscopy. Comparing to pure Ni, the obtained Ni–W coatings exhibited a clearly decreased corrosion resistance (in terms of corrosion current density and polarization or charge transfer resistance at the open circuit potential). Despite of the quite wide range of composition of the alloys under test, the related grain refinement, and the transition to the amorphous structure, no clear relation between the corrosion rate and W content was detected. This behavior can be a result of the interplay of the activating effect of grain refinement or preferential dissolution of W from one side and diffusion barrier action or inhibition provided by the surface film of W oxidation products from the other side. The differences observed in the corrosion resistance of Ni–W coatings are more related to their morphological imperfections arising from various deposition conditions than to the W content. Some samples showed a rather non-uniform nature of corrosion (pronounced attack along cracks). An inversion in the dissolution behavior of Ni–W and unalloyed Ni was observed with increasing anodic potential. Contrary to pure Ni, Ni–W coatings were resistant to pitting corrosion in NaCl solution. Contribution to the Fall Meeting of the European Materials Research Society, Symposium D: 9th International Symposium on Electrochemical/Chemical Reactivity of Metastable Materials, Warsaw, 17th–21st September, 2007.  相似文献   

15.
Ternary Ni–Mo–P thin films have been electrodeposited from citrate‐based electrolyte onto graphite substrates for application as anode catalysts for ethanol electrooxidation. The operating deposition parameters were optimized to produce Ni–Mo–P alloy films of outstanding catalytic activity. The phase structure of the deposits was evaluated employing X‐ray diffraction technique. Morphology and chemical composition of the deposited alloy films were studied using scanning electron microscopy and energy‐dispersive X‐ray analysis, respectively. The results demonstrated that the rate of Ni–Mo–P deposition increases with increasing the ammonium molybdate concentration in the plating electrolyte up to 10 g l?1. Also, the amount of Mo in the deposits increases with increasing the ammonium molybdate concentration up to 7.5 g l?1, and the maximum Mo content in the film was 9.1 at.%. The catalytic activity of Ni–Mo–P/C alloy films has been evaluated towards electrooxidation of ethanol in 1.0 M NaOH solution by using cyclic voltammetry and chronoamperometry. The catalytic performance of the prepared anodes as a function of the amount of Mo was studied. The results showed an increase in the oxidation peak current density of ethanol with increasing the Mo at.% in the deposited alloy films. Additionally, Ni–Mo–P/C electrodes displayed significantly improved catalytic activity and stability towards electrooxidation of ethanol compared with that of Ni–P/C electrode. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

16.
Cu以其优异的导电性、导热性和易加工性广泛用于工农业生产中.自然Cu的腐蚀和防腐成为人们很关注的问题.人们已经注意到,Cl-对Cu的腐蚀有影响,并进行过一些研究.但目前使用光电化学方法研究这一问题的文章尚不多见,特别是利用测量开路光电压及其瞬态波形这一现场的、无损的、灵敏的监测方法研究户对Cu电极腐蚀全过程的文章尚未见到.本文正是利用如上方法及XPS,AES方法,研究了Cl-对Cu电极腐蚀的全过程,取得了一些有意义的结果.1实验方法Cu电极用99.99%(质量分数)的Cu制成,面积约为39mm2;电极底部由Cu导线焊接引出,…  相似文献   

17.
用阴极电沉积法从钼酸盐和磷酸盐温和溶液中获得了黑色的不锈钢转化膜,该膜具有良好的热稳定性。电子能谱(XPS和AES)分析表明,膜厚约为820nm,膜的表面铝以Mo(Ⅵ)存在,而在膜内则以Mo(Ⅵ)与Mo(Ⅳ)共存。从AES深度剥蚀曲线的组成恒定区求得膜的组成为:O50.9%,Mo29.4%,P12.6%和Fe7.1%。循环伏安的氧化峰也证明膜内存在Mo(Ⅳ)。  相似文献   

18.
研究了Pd部分替代Mg对Mg0.9-xTi0.1PdxNi(x=0.04~0.1)贮氢合金腐蚀性能的影响. 利用机械合金化方法制备了Mg0.9-xTi0.1PdxNi(x=0.04~0.1)贮氢合金. XRD和TEM分析表明经120 h球磨后该合金完全非晶化. 循环充放电测试结果表明, Pd的替代有效地延长了Mg0.9-xTi0.1PdxNi(x=0.04~0.1)合金的循环寿命. 采用开路电位测量, 阳极极化, 电化学阻抗和X射线光电子能谱研究了该合金的腐蚀行为. 结果表明, 随着Pd含量增加, 合金腐蚀电位正移, 初始腐蚀电流下降, 腐蚀电流增加的速度变缓. 采用本文提出的等效电路模型较好地拟合了合金的电化学阻抗谱. 分析表明, 随着Pd含量的增加, 合金表面钝化膜厚度和电阻逐渐增大. X射线光电子能谱分析表明, Pd的加入减弱了合金在充放电过程中的氧化程度. 当Pd含量达到0.1时, Mg0.9-xTi0.1PdxNi(x=0.04~0.1)合金的耐腐蚀性能最好, 其放电容量保持率最高.  相似文献   

19.
Summary The alloys Fe17.8Cr, Fe16Cr2.4Mo and Fe18Cr14Ni2.5Mo (at%) were polarized in 0.5 mol/l H2SO4 or in 0.1 mol/l HC1 + 0.4 mol/l NaCl. The composition of the oxide layer and of the metallic layer beneath the oxide and the kinetics of the passive layer formation were determined by AES and XPS. In the active region, selective dissolution of Fe leads to an enrichment of Cr, Ni and Mo at the metal/electrolyte interface. In the passive region, the thickness of the rapidly formed passive layer is determined by the potential. The chromium content of the passive layer approaches a stationary, high value. The passive layer essentially consists of the anions O2- and OH and of the cations of Cr, Fe, Mo, whereas Ni — and less pronounced Mo — are enriched below the layer.  相似文献   

20.
Corrosion behavior and resistance of plasma electrolyte oxidation (PEO)-treated AZ31 Mg alloy were investigated by immersion and potentiodynamic polarization tests in 0.5 M NaCl solution in view of the PEO film thickness and sealing treatment of the PEO films in boiling water. The PEO films were formed using pulse current for various durations in 1 M NaOH?+?0.5 M NaF solution. Filiform corrosion was observed during the immersion test while pitting corrosion occurred during the potentiodynamic polarization test, irrespective of sealing treatment of the PEO films. Corrosion resistance of AZ31 Mg alloy was improved remarkably by the formation of thicker PEO films and their sealing treatments.  相似文献   

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