X70钢在含H2S的弱酸性溶液中的腐蚀行为的电化学研究

用动电位扫描法和电化学阻抗谱研究了X70钢在含H2S弱酸性溶液中的腐蚀行为,讨论了酸度、温度、浸泡时间、极化电位对X70钢腐蚀行为的影响。结果表明,恒温下,随着溶液酸度的增加,促进了腐蚀反应阴极过程的进行;当酸度一定时,随着温度的增加,X70钢的自腐蚀电流逐渐增大,自腐蚀电位先负移后正移;随着浸泡时间的延长,FeS保护膜变得更加稳定,抑制作用增强;FeS保护膜在一定电位范围内可对电极反应起到抑制作用,当电位增加到更高的数值时,这种保护膜就会被破坏而失去保护作用。     

钛基Ni-Co-P非晶合金镀层电极的析氢性能

通过电沉积在钛基体上制备了非晶态Ni-Co-P合金镀层.在7mol/L NaOH溶液中进行的电化学测试结果表明,Ni-Co-P合金电极的析氢过电位明显低于镀镍阴极和纯钛阴极;计算了电极析氢反应的电化学动力学参数,表明非晶态Ni-Co-P合金电极具有较好的析氢电催化活性.     

低温熔盐中Al~(3+)在钨钼电极上的阴极电化学行为研究

本文研究了Na_3AlF_6-AlF_3-Al_2O_3低温熔盐体系中Al~(3+)的阴极行为。电解质分子比为1.59,实验温度为850℃,采用Al~(3+)/Al为参比电极,钨丝、钼丝为工作电极,石墨为辅助电极。运用循环伏安法、计时电位法研究了Al~(3+)的电化学行为。分别在钨电极、钼电极上以-0.7 V进行恒电压电解,采用SEM、EDS对阴极电解产物进行了表征,采用XRD分析手段分析了电解产物的物相组成。结果表明,在工作电极为钨或钼时,Al~(3+)的电化学反应过程是由扩散控制的准可逆过程;Al~(3+)在两种电极上的扩散系数分别为0.93×10~(-5)cm~2/s和1.28×10~(-5)cm~2/s;铝在两种电极上沉积时,与两种电极材料都会发生合金化反应。     

管线钢在含H_2S的NaCl溶液中氢渗透行为的研究

通过电化学渗氢技术研究了施加不同阴极电位条件下含不同H2S浓度的3.5%NaCl溶液中X70管线钢的氢渗透行为.结果表明,稳态渗氢电流P∞随H2S浓度的增大而逐渐增大,但一定时间内,渗透过试样的氢原子摩尔数并不随之单调增加;氢原子的渗透受到阴极电位的控制,阴极电位越负,渗氢电流越大;在一定电位范围内,稳态渗氢电流P∞和一定时间内渗透过试样的氢原子摩尔数N与阴极电位呈线性关系.扩散系数与试验条件无关.     

管线钢在含H2S的NaCl溶液中氢渗透行为的研究

通过电化学渗氢技术研究了施加不同阴极电位条件下含不同H2S浓度的3.5%NaCl溶液中X70管线钢的氢渗透行为.结果表明,稳态渗氢电流P∞随H2S浓度的增大而逐渐增大,但一定时间内,渗透过试样的氢原子摩尔数并不随之单调增加;氢原子的渗透受到阴极电位的控制,阴极电位越负,渗氢电流越大;在一定电位范围内,稳态渗氢电流P∞和一定时间内渗透过试样的氢原子摩尔数N与阴极电位呈线性关系.扩散系数与试验条件无关.     

N80碳钢CO2／HAc腐蚀电化学过程

采用动电位扫描、恒电位极化和电化学交流阻抗测试技术,研究了乙酸(HAc)对N80碳钢在50℃、饱和CO2的1%NaCl溶液中的电化学腐蚀行为的影响,并讨论了阴极、阳极的反应机理.研究表明:HAc能够直接在电极表面还原,使阴极极限电流增加.HAc未改变阳极反应机理,但能够加速中间产物的形成/溶解过程,从而加速阳极溶解过程.在饱和CO2溶液体系,乙酸盐易与碳酸生成HAc,而参与电化学反应.因此,无论是HAc还是乙酸盐均能够加速N80碳钢电极的CO2腐蚀.     

表面活性剂对铝合金表面电化学沉积硅烷膜层的影响

采用交流阻抗技术研究了表面活性剂对不同条件下双-1,2-[3(三乙氧基)硅丙基]四硫化物硅烷在铝合金表面阴极电化学辅助沉积成膜的影响.研究表明:在硅烷溶液中加入表面活性剂进行改性,可降低硅烷在铝合金表面电化学沉积的阴极沉积电位,抑制硅烷沉积过程中的析H2作用,改善电极界面区域硅烷成膜环境.试验证明:硅烷溶液中表面活性剂的最佳改性浓度为0.03%,在此浓度下,铝合金表面硅烷阴极电沉积的最佳沉积电位为-1.6V.     

20号钢在HCl-H2S-H2O溶液中的腐蚀行为

利用极化曲线和电化学阻抗,结合扫描电镜和能谱分析,对20号钢在90℃HCl-H2S-H2O溶液中的腐蚀行为进行了研究.结果表明,当溶液中存在H2S时,电极表面形成的FeS膜对HCl的侵蚀具有一定的阻碍作用;随H2S浓度的增加,膜电阻、电荷转移电阻逐渐减小,说明膜的敛密性下降,腐蚀加重;当溶液中HCl较高时,FeS膜出现...     

RuO2/TiO2电极在海水电解防污中的电化学行为

研究了RuO2/TiO2电极在海水电解时的电化学行为。结果表明,在100mA/cm2电流密度下,阴、阳极间距d=5mm时可提高电流效率,减少能耗,为较理想的电解条件。同时阴极的电极电位达到-820～-1450mV(SCE),因而得到电化学保护。     

Cu表面氨基酸混合组装体系的缓蚀作用

考察了半胱氨酸自组装膜Cu电极在0.5 mol/L HCl溶液中的电化学行为,结果表明半胱氨酸自组装膜导致Cu电极的自腐蚀电位负移,能够在一定程度上抑制Cu电极的阴极电化学过程｡在此基础上,通过静电沉积技术,将十二酸接枝到Cu表面半胱氨酸分子上｡结果显示,十二酸修饰的半胱氨酸自组装膜对Cu电极的阴极电化学过程抑制作用进一步增强,提高了对Cu的保护｡     

EVOLUTION OF SULFIDE SCALES ON Fe-Mo ALLOYS DURING SULFIDATION

ＥＶＯＬＵＴＩＯＮＯＦＳＵＬＦＩＤＥＳＣＡＬＥＳＯＮＦｅＭｏＡＬＬＯＹＳＤＵＲＩＮＧＳＵＬＦＩＤＡＴＩＯＮ①ＬｉｕＨａｉｐｉｎｇ，ＱｉＨｕｉｂｉｎ，ＨｅＹｅｄｏｎｇ，ＺｈｕＲｉｚｈａｎｇＯｐｅｎＬａｂｏｒａｔｏｒｙｆｏｒＣｏｒｒｏｓｉｏｎａｎｄＥｒ...     

Effects of cathode materials on discharge characteristics of Li-B alloy/FeS2 thermal battery

１　ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｇｅｎｅｒａｌ,ＦｅＳ２ｉｓｔａｋｅｎａｓｃａｔｈｏｄｅｍａｔｅｒｉａｌｔｏｆｏｒｍｍｏｌｔｅｎｓａｌｔｂａｔｔｅｒｙｗｉｔｈｍｏｓｔａｄｖａｎｃｅｄａｎｏｄｅｍａｔｅｒｉａｌｓＬｉＢａｌｌｏｙｓ［１］．Ｅｖｉｄｅｎｔｌｙ,ｔｈｅｓｔａｔｅｏｆＦｅＳ２ｈａｓｃｏｒｒｅｓｐｏｎｄｉｎｇｅｆｆｅｃｔｓｏｎｔｈｅｄｉｓｃｈａｒｇｅｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＬｉＢ／ＦｅＳ２ｍｏｌｔｅｎｓａｌｔｂａｔｔｅｒｉｅｓ．Ｉｎｖｅｓｔｉｇａｔｉｏｎｏｎｔｈｉｓｐｒ…     

Density functional study for structure and electronic properties of FeS_2(100)

1　INTRODUCTIONThereactivityoftheFeS2 (pyrite)surfaceisofparticularimportantintheengineeringapplications ,includingsulfidemineralsflotation[1] ,bioleachingoflow gradechalcopyrite containingore[2 ] ,coal pro cessing ,hydrometallurgy ,environmentalengineer ing ,geochemistry ,andphotovoltaiccell,etc[3] .Es pecially ,anunderstandingofhow pyritesurfacesin teractwithflotationreagentmoleculeswillaidinthedesignofmoreeffectiveflotationsuppressants ,whichwouldeffectivelyseparatethedesirableoresfrom…     

Fe^2＋对碳钢的微生物腐蚀作用的影响

硫酸盐还原菌（ＳＲＢ）对碳钢的腐蚀与其腐蚀产物ＦｅＳ膜的状态有关。实验表明,当介质中的Ｆｅ＾２离子浓度低于５０ｍｇ／Ｌ时,ＳＲＢ的存在对碳钢起保护作用,其腐蚀产物膜致密,阻碍了介质与铁的作用,而且生物膜（ｂｉｏｆｉｌｍ）＾［１］中的细菌数当于介质中的菌量;当介质中Ｆｅ＾２浓度高于５０ｍｇ／Ｌ时,ＳＢＲ的腐蚀产物膜厚且疏松,ＦｅＳ成为腐蚀微电池的阴极,对碳钢的腐蚀起促进作用,生物膜的存在影响了杀菌剂     

FV（520）B不锈钢在CO2/H2S共存条件下的腐蚀行为

目的研究长输管线压缩机叶片材料FV(520)B不锈钢在高含H_2S、H_2O、CO_2条件下的腐蚀行为。方法利用高温高压反应釜模拟特定工况,在H_2S分压为0.9 MPa、CO_2分压为0.6 MPa、温度为150℃的条件下于5 g/L的氯化钠溶液中制备硫化腐蚀层,利用XPS、SEM、XRD等手段对腐蚀层的成分及结构进行分析。结果 FV(520)B不锈钢的腐蚀速率逐渐降低,试样表面粗糙度先增大后下降,腐蚀产物主要为FeCO_3、Fe_3O_4、FeS、FeS_2、S、Cr_2S_3、Cr_2O_3和Cr(OH)_3。结论在腐蚀前期,FeS的形成速率大于FeS_2、S,腐蚀产物颗粒不断长大。形成完整的Cr_2O_3、Cr(OH)_3保护膜后,腐蚀得到抑制,此时腐蚀反应主要为FeS_2、S的生成,试样表面腐蚀产物颗粒尺寸变小,试样表面粗糙度降低。     

A SIMPLIFIED SUBREGULAR SOLUTION MODEL DESCRIBING THE ACTIVITES OF MgCl 2 IN BOTH KCl MgCl 2 LiCl AND CaCl 2 MgCl 2 NaCl MOLTEN SALT SYSTEMS

１．ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅａｃｔｉｖｉｔｉｅｓｏｆＭｇＣｌ２ｉｎｔｈｅＬｉＣｌＭｇＣｌ２ＫＣｌａｎｄＣａＣｌ２ＭｇＣｌ２ＮａＣｌｍｏｌｔｅｎｓａｌｔｅｌｅｃｔｒｏｌｙｔｅｓａｒｅａｎｉｍｐｏｒｔａｎｔｐａｒａｍｅｔｅｒｔｏｔｈｅｅｌｅｃｔｒｏｌｙｔｉｃｐｒｏｄｕｃｔｉｏｎｏｆｍａｇｎｅｓｉｕｍ．ＬｉＣｌａｎｄＫＣｌｃａｎｏｂｖｉｏｕｓｌｙｉｍｐｒｏｖｅｔｈｅｐｒｏｐｅｒｔｉｅｓｏｆｔｈｅｅｌｅｃｔｒｏｌｙｔｉｃｓｏｌｕｔｉｏｎ．ＮａＣｌａｎｄＣａＣｌ２ａｒｅｔｈｅｍａｊｏｒｃｏｍ…     

Preparation of Mo nanoparticles through hydrogen reduction of commercial MoO2 with the assistance of molten salt

In the present work, the hydrogen reduction of commercial MoO₂ with the assistance of molten salt has been investigated at 720–850 °C. In the case of no salt addition, the prepared Mo particles maintained the big platelet shape of raw MoO₂ powders. However, after adding a small amount of salt (0.1% NaClKCl binary salt, MgCl₂KCl binary salt, or LiCl mono salt), Mo nanoparticles were prepared successfully. It was found that a small amount of molten salt can help Mo to nucleate dispersedly and its growth via chemical vapor transport (CVT) mechanism can be controlled by reducing temperature. At 750 °C, when the NaClKCl binary salt was used, the obtained Mo nanoparticles had both good dispersion and small average size of about 70 nm. Kinetics analyses indicated that the rate controlling step for the hydrogen reduction of MoO₂ was the interface chemical reaction, and after adding salt, the reaction rate constant decreased dramatically, relative to that without salt. The extracted activation energies for pure MoO₂, MoO₂ with 0.1% NaClKCl binary salt and MoO₂ with 0.1% LiCl mono salt were 76.13 kJ/mol, 117.45 kJ/mol and 97.23 kJ/mol, respectively.     

Current efficiency in electro-winning of lanthanum and cerium metals from molten chloride electrolytes

The objective of this study is to prepare lanthanum and cerium metals by fused salt electrolysis of their anhydrous chloride in molten media such as LiCl-KCl, NaCl-KCl, KCl, NaCl, and LiCl and to characterize the metal deposit by X-ray diffraction, energy dispersive X-ray fluorescence, and inductive coupled plasma-atomic emission spectroscopy. Deposit metal of purity more than 99 % was obtained in each of the experiments. The entire process starting from preparation of anhydrous lanthanum/cerium chloride to electrolysis yielding of metal deposits has been described. The effect of process parameters such as temperature, electrolyte composition, and current density on the current efficiency was studied. All these parameters were varied to get the highest current efficiency and metal yield. The major non-rare earth impurities with the deposit are found to be Fe, Cr, and Ni along with ～1×10-3 of total gaseous impurities.     

Corrosion of type 316L stainless steel in molten LiCl–KCl salt

Pyrochemical reprocessing in molten chloride salt medium has been considered as one of the best options for the reprocessing of spent metallic fuels. The AISI 316L stainless steel (SS) is envisaged as a candidate material for the fabrication of components for various unit operations like salt preparation vessel, electro‐refiner and cathode processor, on which ceramic coatings with metallic bond coat will be applied by the thermal plasma spraying. The unit operation like electro‐refining is carried out in the molten lithium chloride–potassium chloride (LiCl–KCl) eutectic salt at 773 K in argon atmosphere. The corrosion behaviour of the container vessel in molten chloride salts is therefore important, hence corrosion tests were carried out in a molten salt test assembly under argon gas atmosphere. The present paper discusses the corrosion behaviour of 316L SS in the molten LiCl–KCl eutectic salt at 873 K. The 316L SS samples were immersed in the molten LiCl–KCl eutectic for 25, 100 and 250 h, while 316L SS with yttria stabilized zirconia coating was exposed for 1000 h. The exposed samples were examined by optical and scanning electron microscope for corrosion attack. The X‐ray mappings of the cross‐section of the degraded layer onto the 316L SS indicated that the mechanism of corrosion corresponds to the selective diffusion of Cr to the surface with the formation of voids below, and the formation of chromium compounds at the surface. The results of the present study indicated that the yttria stabilized zirconia coating onto the 316L SS exhibits a better corrosion resistance in molten chloride salt than with uncoated 316L SS.     

Effects of Mo substituted Nb on magnetic properties of Finemet alloy

Different Mo contents have been added into traditional Finemet alloy to form Fe73.5Cu1Nb3-x MoxSil3B9.5( x = 0 - 3) alloys. The change in DC and AC magnetic properties with Mo for Nb substimtlon was investigated. The results show that, with adding Mo, although the DC relative permeability decreases and the coercive force increases slightly,the saturation flux density Bs can be increased, and the core loss of the alloy can be decreased. The AC permeability of samples contained Mo is higher than that of alloy without Mo content. Fe73.sCu1Nb1Mo2Si13B9.5 alloy has the highest saturation flux density Bs. Fe73.sCu1Nb2Mo1Si13B9.5 alloy has the best frequency dependence on the AC permeability and core loss.