Preparation and electrocatalytic properties of tungsten carbide electrocatalysts

1　ＩＮＴＲＯＤＵＣＴＩＯＮ ｉｎ 1 5 0℃ .Ｍａａｓ[1 0 ] ａｌｓｏｍａｎｕｆａｃｔｕｒｅｄｔｈｅＨ2 Ｏ2 ｆｕｅｌｃｅｌｌｓｔａｃｋｓｗｉｔｈｔｈｅｏｕｔｐｕｔｐｏｗｅｒｕｐｔｏ 1ｋＷ ,ａｎｄｔｈｅｐｒｏｐｅｒｔｉｅｓｏｆｔｈｅａｓ ｐｒｅｐａｒｅｄｆｕｅｌ     

铸态Mm(NiCoMnAl)5.1Bx贮氢合金电化学性能研究

本文研究了B含量对铸态非化学计量比贮氢使合金Mm(NiCoMnAl)5.1Bx的相结构及其电化学性能的影响。结果表明，加B合金中除了CaCu5相以外还含有一定量的第二相MmCo4B，且随着B元素含量的增加而增加；B的加入有利于提高合金的活化性能和高倍率放电性能，合金的循环寿命亦有所提高，但不利于合金的放电容量和放电电压性能。     

碳钢在流动3%氯化钠溶液中的腐蚀机理的探讨

本文利用自行设计的模拟流动状态的装置,研究了碳钢在流动3%NaCl溶液中的腐蚀规律及施加阴极电流后对腐蚀的影响。结果表明:随着相对流速的增大,碳钢的腐蚀随之加剧,并发现存在一个临界相对流速值。当相对流速小于此值时,腐蚀主要受电化学因素影响。而相对流速大于此值时,流体力学因素开始明显起主导作用,并与电化学因素间的协同效应增强,导致腐蚀速度急剧上升。施加阴极电流后,不仅抑制了电化学因素引起的腐蚀,而且大幅度地削弱了电化学因素与流体力学因素间的协同效应,从而使腐蚀速度大大降低。     

Electrochemical behavior of YAG laser-welded NiTi shape memory alloy

Electrochemical behaviors of laser-welded Ti-50.6%Ni（mole fraction） shape memory alloy and the base metal in 0.9% NaCl solution were investigated by electrochemical techniques as corrosion potential measurement, linear and potentiodynamic polarization. The results indicate that the laser-welded NiTi alloy is less susceptible to pitting and crevice corrosion than the base metal, which is demonstrated by the increase in polarization resistance（Rp） and pitting potential（φpit） and decrease in corrosion current density（Jcorr） and mean difference between φpit and φprot values. It is confirmed by scanning electron microscope micrographs that pits could be observed on the surface of base metal but not on the surface of laser-welded alloy after potentiodynamic tests. An improvement of corrosion resistance of laser-welded NiTi alloy could be attributed to almost complete dissolution of inclusions upon laser welding.     

Electrodeposition of dixanthogen（TETD） on pyrite surface

The electrochemical reaction of xanthate on the surface of pyrite was studied using cyclic voltammogrametry, chronopotentiometry and rotating-disc electrode measurements.Experimental results demonstrate that the first step in the reaction is electrochemical adsorption of xanthate ion,and then the adsorbed ion associates with a xanthate ion from the solution and forms a dixanthogen on the pyrite electrode surface.The diffusion coefficient of butyl xanthate on pyrite electrode surface can be determined to be about 1.09×10- 6cm2/s.Using the galvanostatic technique,the kinetic parameters of oxidation of the butyl xanthate ion on the pyrite surface are calculated as Ja=200μA/cm2 ,β=0.203 and J0=27.1μA/cm2.     

热处理对La0．7Mg0．3Ni2．8Co0．5贮氢合金电化学性能的影响

La0．7Mg0．3Ni2．8Co0．5贮氢电极合金经过适当热处理后(1123K)，最大放电容量、循环稳定性、高倍率放电性能(HRD)、交换电流密度(I0)以及极限电流密度(IL)都有明显改善，铸态合金电极的最大放电容量为392mAh／g，放电电流密度，Id=2000mA／g时，HRD2000=74．0％，I0=266．7mA／g，IL=3425．5mA／g；经1123K保温8h退火的合金电极的最大放电容量提高到414mAh／g，HRD2000=76．2％，I0=407．9mA／g，IL=3753．6mA／g。X射线衍射(XRD)分析表明，衍射峰宽度随着退火温度的升高而变窄，其原因是合金经退火处理相结构的变化和成分的均匀化。     

On the electrochemical nature of hot-corrosion attack in Ni-Cr alloys

Hot-corrosion attack on gas-turbine components has been a problem of practical importance for over two decades. The nature and the extent of corrosion are influenced by the type of contaminants, the alloy constituents, and temperature. The hot-corrosion process is quite complex. There is controversy regarding the role of alloying elements, and whether the process is chemical or electrochemical in nature. In this investigation, an attempt has been made to investigate the role of Al and Ti in influencing the hot-corrosion attack of Ni-20 wt. % Cr alloys in molten Na₂SO₄-NaCl mixtures. It was found that Ni-Cr-Al alloys undergo a localized, heavy-blister attack under certain experimental conditions which is electrochemical in nature. An electrochemical model has been proposed which can satisfatorily explain the nature and kinetics of the localized blister corrosion.     

Effects of pH value of reaction solution on structure and electrochemical performance of calcium-containing active material of secondary zinc electrodes

The calcium-containing active material of secondary alkaline zinc electrodes was prepared by a chemical coprecipitation method and characterized by scanning electron microscopy(SEM) and X-ray diffractometry(XRD).Their electrochemical performance was tested by the Galvanstatic charge-discharge method. The experimental results show that the sample synthesized at pH: 11. 15 has a typical calcium zincate crystal. The zinc electrode using this sample as active material shows higher discharge capacity, more negative discharge plateau potential and longer cycle lifetime.     

薄壁铸造铸态贮氢合金的电化学性能及微观分析

讨论了壁厚(1～10mm)对无钕低铈低钴LPC(NiCoMnAlCuFeSi)5和商用成分Mm(NiCoMnAl)5铸态贮氢合金电化学性能的影响。研究发现：10mm厚的两种合金活化性能均优于1～6mm厚度合金；在0.2C充放电制度下，两种合金的放电容量对铸锭厚度均不敏感，LPC(NiCoMnAlCuFeSi)。合金的最大容量约为285mAh／g，Mm(NiCoMnAl)5合金的放电容量约为300mAh／g；在1C充放电制度下，LPC(NiCoMnAlCuFeSi)5合金的最大容量约为250mAh／g，对壁厚不敏感，Mm(NiCoMnAl)5合金的放电容量为250～280mAh／g，对壁厚敏感，并且前者显示出更好的循环稳定性。造成LPC(NiCoMnAlCuFeSi)。合金电化学性能对冷却速度不敏感的主要原因是元素Cu、Fe和Si的作用；晶胞参数和内应力等因素的交互作用也对该合金的性能有一定的影响。     

电化学法制备BaMoO_4和SrMoO_4薄膜的生长特性比较研究(I):共性分析

采用恒电流电化学技术直接在金属钼片上制备了具有白钨矿结构的钼酸盐(BaMoO4、SrMoO4)薄膜,对制备时间分别为10s直到50min的BaMoO4薄膜和制备时间分别为1min直到100min的SrMoO4薄膜的生长情况进行了SEM测试,并对相应结果进行了对比分析。研究表明:用电化学法制备BaMoO4和SrMoO4晶态薄膜,其生长特性既具有共性,也具有鲜明的个性。其共性特征是:1)成膜机制相同;2)薄膜生长初期就有比较完整的晶核生成;3)晶核和晶粒优先选择在金属基体缺陷(折叠、划痕、缺陷、凹凸不平等)处堆砌和生长;4)基体上晶粒的数量随着制备时间的增加而增加,晶粒的尺寸也随着时间的延长而长大,晶粒逐渐从稀疏分布到布满整个基体;5)在具有白钨矿结构的钼酸盐晶态薄膜的生长过程中,晶体的{111}面总是显露的。其鲜明的个性特征将在另文中讨论。该研究结果对功能晶态薄膜的生长(特别是利用电化学技术制备功能晶态薄膜的生长)和了解及预测白钨矿结构的晶态薄膜的生长习性,均具有重要意义。