321不锈钢点蚀电位影响因素的研究

通过正交设计和对比实验研究了温度、pH值以及Cl-和SO2-4含量对321不锈钢点蚀电位的影响.正交设计表明,温度和Cl-(Cl-≥0.014mol/L)含量对点蚀电位Eb的影响显著,但pH值(6～9)则没有影响.对比实验表明,当Cl-≤0.014 mol/L时,Cl-对Eb没有影响,当Cl-＞0.014 mol/L,则Eb随Cl-浓度对数升高而线性下降.点蚀电位随温度升高而下降.如不含Cl-,则SO2-4对Eb没有影响,当Cl-=0.028 mol/L时,Eb随SO2-4浓度升高而升高,并趋于稳定值.     

滴定法连续快速测定冰铜中的铜铅锌

采用一次称样，一次分解试样，以H2SO4，K2SO4为沉淀剂，使Pb生产K2SO4．PbSO4复盐沉淀与干扰元素分离．该复盐沉淀的溶解度比PbS04沉淀小，少量的Cl^-，NO3^-不影响复盐沉淀，省去了H2SO4冒烟步骤，加入乙醇可加速PbSO4的沉淀，流水冷却30min即可沉淀完全．沉淀用NaAc—HAc缓冲溶液溶解．用EDTA标准液滴定铅，滤液以水定容，分取部分溶液2份，一份加入氟化钾、琉腮和盐酸羟胺溶液，消除Fe，Cu的干扰，用EDTA标准液滴定法测定锌，另一份溶液加入三氯化铁溶液，用乙酸铵溶液弼解酸度使pH=3-4，碘量法测定铜．     

在Q235钢表面原位生长的氧化铁膜对其在含Cl-溶液中腐蚀行为的影响II-原位生长的α-FeOOH膜的研究

利用动电位极化曲线和交流阻抗谱等电化学测量技术研究了Q235钢表面原位生长的α-FeOOH膜在0.25 mol/L Na2SO4+10-4 mol/L NaCl、0.25 mol/L Na2SO4+10-3 mol/L NaCl、0.25 mol/L Na2SO4+10-2 mol/L NaCl水溶液中的电化学性能.在不同浓度的Cl-溶液中α-FeOOH膜对侵蚀性离子的作用机制.结果表明,Q235钢表面原位生长的α-FeOOH膜在10-4 mol/L 到10-2 mol/LCl-浓度范围内,对基材均无保护作用;但当Cl-含量为10-2 mol/L时,α-FeOOH膜的膜电阻及转移电阻皆比低氯离子浓度的要大,此时α-FeOOH膜表现出一定的抗腐蚀能力.     

铝表面聚苯胺的电化学合成与性能研究

目的 提高铝在含氯离子介质中的耐腐蚀性能.方法 在含有0.4 mol/L苯胺的1 mol/L硫酸中,采用恒电位法和循环伏安法在铝表面电化学合成聚苯胺,用红外光谱、紫外光谱和扫描电镜对聚苯胺的结构和形貌进行表征.通过动电位极化曲线和电化学交流阻抗测试,研究聚苯胺在0.6 mol/L NaCl、0.6 mol/L HCl、0.3 mol/L H2 SO4和0.3 mol/L H2 SO4+0.6 mol/L NaCl几种腐蚀介质中对铝的防护性能.结果 红外光谱表明,合成的是硫酸掺杂态聚苯胺.紫外-可见光谱表明,不同电化学方法 合成的聚苯胺吸收峰位置相近.扫描电镜观察显示,恒电位法制备的聚苯胺为纳米短棒状结构,而循环伏安法制备的聚苯胺呈现出颗粒状结构.聚苯胺涂层铝在各种腐蚀溶液中的自腐蚀电位都比铝正移,在0.3 mol/L H2 SO4中,恒电位法和循环伏安法制备的试样自腐蚀电位分别提高了769、894 mV.相比于恒电位法,循环伏安法制备的聚苯胺涂层具有更好的防腐蚀性能,在0.3 mol/L H2 SO4+0.6 mol/L NaCl中的保护效率高达91.69%,在0.6 mol/L HCl和0.6 mol/L NaCl溶液中的保护效率分别为80.40%和6.54%.结论 聚苯胺涂层在酸性溶液中比在中性溶液中具有更明显的腐蚀防护效果,在0.3 mol/L H2 SO4+0.6 mol/L NaCl强腐蚀性溶液中能对铝基体起到良好的防腐蚀作用.     

反萃更新中空纤维液膜对四价铈的回收提取研究

研究了Ce4+在以2-(二乙基己基)磷酸(P204)为流动载体,煤油和P204的混合溶液作为膜溶液,膜溶液和解析剂H2SO4溶液组成更新相的反萃更新中空纤维液膜(SRHFLM)中的提取行为;考察了料液酸度、更新相H2SO4浓度、膜溶液与H2SO4溶液体积比、不同载体浓度对Ce4+提取的影响,得出了以下Ce4+最优提取条件:更新相H2SO4溶液浓度2.50mol/L,膜溶液与H2SO4溶液体积比2:1,载体浓度控制在0.200mol/L,料液相酸度为0.05mol/L。在最优分离条件下,当Ce4+的初始浓度为1.00?10-4mol/L时,Ce4+在45min时提取率达到92.2%。最后提出了Ce4+在SRHFLM中的学渗透系数动力学模型。     

铀在三种溶液中的动电位极化和电化学阻抗谱研究

用动电位极化和电化学阻抗谱（EIS）研究铀在0.5 mol/L H2SO4溶液、1 mol/L NaOH溶液和1 mol/L Na2SO4溶液中的腐蚀电化学行为。结果显示,铀在H2SO4溶液和Na2SO4溶液中的动电位极化曲线有类似的极化趋势,而在NaOH溶液中则有明显的钝化现象。EIS谱均有明显的容抗弧特征。利用软件对电化学阻抗谱进行拟合,得到了3种溶液中铀的电化学阻抗谱等效电路,拟合的阻抗谱与实验测得的阻抗谱拟合得比较好,拟合方差在10-3数量级。     

316L不锈钢在有机胺脱硫溶液中的耐蚀性

采用浸泡方法研究了316L不锈钢在烧结烟气有机胺脱硫溶液中的腐蚀行为,主要对pH、温度、Cl-浓度和SO42-浓度变化引起的影响进行了分析。结果表明,316L不锈钢在脱硫溶液中存在点蚀行为,随着溶液pH、温度、SO42-浓度(60~140g/L)、Cl-浓度(1~10g/L)因素的变化,均有不同程度的腐蚀;但当pH4、温度80℃、ρ(Cl-)10g/L时,对316L的腐蚀影响较为明显。     

回用水中杂质离子对锌电解过程中Pb-Ag阳极钝化的影响(英文)

采用线性扫描伏安法研究了回用水中杂质离子对锌电解过程中Pb-Ag阳极钝化的影响。结果表明:回用水中Cl-和F-的存在将会影响电极的钝化过程。当溶液中H2SO4浓度为180g/L,即酸锌比为3.6,Mn2+浓度为3～5g/L,F-浓度小于42mg/L时有利于Pb-Ag阳极钝化;而当溶液中只存在Cl-时,Cl-浓度必须低于13mg/L才不会影响电极的钝化过程;当溶液中同时存在Mn2+和Cl-且锰氯质量比为8时,电极的钝化过程不会受到Cl-的影响,此时溶液中Cl-的含量最高,可以达到625mg/L。     

超高压铝电解电容器用阳极箔腐蚀工艺研究

采用正交法和单因素实验法,研究了发孔温度、电流密度、时间、Al3+浓度,扩孔温度、电流密度、时间对超高压铝电解电容器用阳极箔比容的影响。结果表明,发孔温度对超高压阳极箔比容的影响最大,Al3+浓度的影响最小。Vfe=700 V阳极箔的腐蚀工艺优化参数:在[Cl-]、[SO2-4]和Al3+浓度依次为1 mol/L、3 mol/L和0.2 mol/L,温度为75℃,0.40 A/cm2电流密度条件下发孔120 s,之后再在1 mol/L的HNO3溶液中,75℃,0.1 A/cm2条件下扩孔500 s,所得腐蚀箔经700 V二级化成,耐压值为663.7 V,比容值达到0.48μF/cm2。     

309不锈钢纳米涂层在酸性溶液中的电化学腐蚀行为

用动电位极化、恒电位极化及交流阻抗技术研究了 309 不锈钢及其溅射纳米涂层在 0.25 mol/L Na2SO4 0.05 mol/L H2SO4 和 0.5 mol/L Nacl 0.05 mol/L H2SO4溶液中的电化学腐蚀行为.结果表明,在 0.25 mol/L Na2SO4 0.05 mol/L H2SO4 溶液中,纳米涂层和不锈钢形成的钝化膜的抗腐蚀能力差别较小;而在 0.5 mol/L NaCl 0.05mol/L H2SO4 溶液中,纳米涂层的耐点蚀性能有了很大提高,这是由于纳米化使涂层表面形成的钝化膜更加致密、更加稳定;同时,通过容抗测量研究了纳米涂层和不锈钢钝化膜的电子结构,并提出了相应的腐蚀机制.     

固体金属在液态金属中的熔化和溶解

固体金属在液态金属中的熔化和溶解存在于铸造生产的多种工艺过程之中,了解熔化和溶解规律对于优化工艺过程或选择工艺参数有重要意义;较系统介绍了固体金属在液态金属中熔化和熔解的微观机制、宏观动力学及其影响因素。     

Golden Section in the Structure of Metals

Main aspects of a new division of crystallography based on the concept of polytopes (four-dimensional polyhedrons) are considered. The possibilities of this concept for describing composite crystal structures of intermetallic compounds and the atomic mechanism of polymorphic transformations are discussed. In all the cases studied icosahedral polyhedrons containing fifth-order symmetry axes play a special role. In its turn, this is a manifestation of the role of golden section in the structure of condensed phases. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 3 – 10, August, 2005.     

Spray Drying in the Metals Industries

This article describes various aspects of spray drying in the metals industries, including process characteristics, atomization techniques, and economic considerations. The section on industrial applications covers mineral processing, cemented carbide powders, iron powders, and thermal spray powders. Included are lists of custom spray-drying companies and suppliers of spray-drying systems.     

Tapping the Memory in Archaeological Metals

Over the last twenty years, there has been a discernable increase in the number of scholars who have focused their research on metal production, working and use in antiquity, a field of study which has come to be known as archaeometallurgy. Materials scientists and. conservators have worked primarily in the laboratory while archaeologists have conducted fieldwork geared to the study of metal technology in a cultural context with laboratory analysis as one portion of the interpretive program.     

工业废料中重金属的回收

<正> 概述 产品市场的激烈竞争与人们对社会物质生活水平的追求,导致了日常用品更新换代的周期也越来越短,随之而来的是产生越来越多的工业垃圾。特别是汽车、家电和电脑等工业的新产品更是日新月异地推出,旧产品迅速淘汰。仅电脑一项,按香港目前资料,每年需淘汰旧电脑达百万台以上,全世界每年需淘汰旧电脑     

Oriented Basic Research in the Metals Industry

Oriented basic research is not a luxury, but is of immediate concern to all industry for the sake of self-preservation. This article discusses the objectives, types, reasons, and conditions for productive basic research in the metals industry.     

Metals in Passive State

A theoretical model [1–4] of the passive state of metals is discussed. This model considers hopping migration of ionic components in the passive layer (PL) lattice, which delivers reactants to take part in interphase processes at PL boundaries with metal and electrolyte, thus binding the latter kinetically and structurally, and defines the dependence of lattice point defectiveness on the potential. The defectiveness results in the transpassivity transition, i.e., the finiteness of the passivity range. A theoretical model of passivity should involve (predict) the transpassivity transition. This serves as a criterion of its consistence. Nonlinear equations of hopping migration in a strong electric field that violates the Ohm law are generalized. Their solution provides a more precise expression for PL point defectiveness and its dependences on the anodic potential, current density, and other parameters. An expression for transpassivity potential that was shown to linearly depend on the defectiveness is derived. A model describing formation of new PL elementary oxide cells at PL–metal interface, i.e., the processing of metal to give passivating oxide is generalized. This process compensates the electrochemical dissolution of PL at the solution boundary. The process of PL origination is also considered, namely, its crystallization in the prepassive range by the mechanism of two-dimensional nucleation of oxide.