铝合金基电沉积Ni-SiC复合镀层的结构及耐蚀性研究

利用SEM观察了Ni-SiC复合镀层的表面形貌结构 ,同时利用电化学方法对铝合金表面电沉积Ni-SiC复合镀层的耐蚀性能进行了研究。结果表明 ,Ni-SiC复合镀层的表面形貌与纯Ni镀层截然不同 ,耐蚀性能优于纯Ni镀层 ,经过 3 0 0℃× 2h热处理后 ,耐蚀性能进一步得到提高     

占空比对Ni-SiC纳米复合镀层性能的影响

采用单脉冲电镀技术,在瓦特型镀液中,制备了Ni-SiC纳米复合镀层。采用X射线衍射仪(XRD)扫描电镜(SEM)分别表征了Ni-SiC纳米复合镀层相结构和表面形貌,通过静态浸泡腐蚀实验、磨损实验和高温氧化性能研究了复合镀层的性能。结果表明,在不同占空比下,Ni-SiC复合镀层的组织主要为Ni晶体;当占空比为70%时,复合镀层的显微硬度最大,为376 HV,摩擦系数最小;900℃、100 h高温氧化增重最小,为7.453 mg·cm-2为0.37。在3.5%Na Cl溶液中静态浸泡30 d后,占空比为70%时的复合镀层的失重最小,失重为3.063 mg·cm-2。     

Ni-SiC纳米复合镀层腐蚀行为的研究

通过电化学阻抗谱测试技术初步确定制备具有较好耐腐蚀性能镀层的工艺参数。利用扫描电子显微镜观察镀层的表面形貌;借助浸泡实验、电化学阻抗谱、极化曲线等方法对比分析了Ni-SiC纳米复合镀层和纯Ni镀层在0.5 mol/L NaCl溶液和1 mol/L HNO_3溶液中的耐腐蚀性能。结果表明,SiC纳米颗粒的加入提高了镀层的耐腐蚀性能,且镀层耐腐蚀性能随镀层中SiC纳米颗粒含量的增加而提高。     

两种镍镀层耐蚀性能的研究

本试验着重研究了瓦特和半光亮两种镍镀层在400、600、800℃的高温氧化行为,并对其在常温5%NaCl+O.5%H2O2溶液中的腐蚀进行了比较:研究表明:两种镍镀层的高温氧化规律基本一致:在盐水溶液中,半光亮镀层表现出较好的耐蚀性能:能谱分析则证实:在高温氧化过程中,明显存在铜向镍镀层中的扩散,这可能有利于增强镀层与基底之间的结合.     

Cr—Mo合金镀层性能研究

用电沉积法在不同镀液温度下制取了Cr-Mo合金镀层。於60℃5％H_2SO_4、40℃10％FcCl_3·6H_2O、30℃3％NaCl水溶液中,对在不同的镀液温度下所制得的镀层进行了腐蚀浸泡试验,测定了点蚀电位、镀层内应力、表面显微硬度以及耐磨性。结果表明,在30℃镀液温度下所获得的Cr-Mo合金镀层,其耐蚀性和耐磨性均优,具有实用性,这同此种镀层的内应力较小、钼元素含量较高等因素有关     

双脉冲Ni-Al2 O3复合镀层在氯化物盐膜下的腐蚀

采用扫描电镜、X射线衍射仪和能谱仪(EDX)对双脉冲法制备的几种Ni-Al2O3复合镀层经高温氧化后的形貌和物相进行分析.结果表明,复合镀层在NaCl的盐膜下均发生了加速腐蚀,表面腐蚀膜疏松且与基体的粘附性较差;Al2O3微粒能细化镀层晶粒,提高镀层的高温抗腐蚀能力,在试验范围内,镀层中的Al2O3微粒含量越高,镀层腐蚀速度越低,并对复合镀层在NaCl的盐膜下的腐蚀机制进行了探讨.     

双脉冲Ni-Al2 O3复合镀层在氯化物盐膜下的腐蚀

采用扫描电镜、X射线衍射仪和能谱仪（EDX）对双脉冲法制备的几种Ni-Al2O3复合镀层经高温氧化后的形貌和物相进行分析。结果表明，复合镀层在NaCl的盐膜下均发生了加速腐蚀，表面腐膜疏松且与基体的粘附性较差；Al2O3微粒能细化镀层晶粒，提高镀层的高温抗腐蚀能力，在试验范围内，镀层中的Al2O3微粒含量越高，镀层腐蚀速度越低，并对复合镀层在NaCl的盐膜下的腐蚀机制进行了探讨。     

Ni-P-纳米TiO2复合镀层的耐蚀性研究

采用全浸泡腐蚀试验，系统研究了Ni—P-纳米TiO2复合镀层在HCl、H2SO4、HNO3、NaOH和NaCl溶液中的耐腐蚀性能。结果表明，Ni—P-纳米TiO2复合镀层比Ni—P化学镀层具有更优异的耐酸、耐碱、耐盐腐蚀的性能；复合镀层在盐和碱性腐蚀液中的耐蚀性优于酸性腐蚀液；Ni—P一纳米TiO2复合镀层在不同腐蚀液中的腐蚀形态明显不同，复合镀层在NaOH、NaCl和HCl溶液中的腐蚀形态为均匀腐蚀型，而在H2SO4和HNO3强氧化性介质中的腐蚀形态则为点蚀穿透型；保持镀层在腐蚀液中的完整性对提高镀层的耐腐蚀性能至关重要。     

07X16H6沉淀硬化不锈钢耐蚀性的研究

通过高温抗氧化、盐雾腐蚀和应力腐蚀试验研究了07X16H6沉淀硬化不锈钢在使用状态(回火态)时的耐蚀性能。结果表明：该不锈钢材料在试验温度500℃、600℃、700℃和800℃下均为完全抗氧化,500℃、600℃和70℃下的氧化动力学曲线符合对数规律,800℃下的氧化动力学曲线则符合抛物线规律;在3．5%NaCl中性盐雾介质中的抗腐蚀性能优良;初步实验表明,该钢在3．5％NaCl溶液中对应力腐蚀断裂很可能不敏感。     

电化学沉积法制备Ni-SiC复合镀层（英文）

采用电化学沉积法通过在电解槽中添加SiC颗粒制备Ni-SiC复合镀层。由于第二相颗粒SiC的加入改善了镀层的性能,使之具有高硬度、耐磨性和耐腐蚀性能等。Ni-SiC复合电镀改善镀层的组织结构并显著提高镀层的质量。采用NiSO_4·6H_2O(35 g/100 mL),NiCl_2·6H_2O(4 g/100 mL),H_3BO_3(3.5 g/100 mL),十二烷基硫酸钠(0.5 g/100 mL),SiC颗粒(0.4~1.0 g/100 m L)体系,在pH值为4,温度35~50℃时,通过电化学沉积法制备Ni-SiC复合镀层。实验探究了温度、电流密度、镀液中碳化硅颗粒含量以及超声波分散时间对镀层中SiC复合量的影响。通过扫描电镜和XRD对镀层进行分析,结果表明:在温度为35~50℃之间复合镀层中SiC的量随温度的增加呈现先增加后减少的趋势;在电流密度为0.026~0.06 A/cm2之间,复合镀层中SiC的含量随电流密度的增加呈现先增加后减小的趋势;镀液中SiC量在0.4~1.0 g/100 m L之间时,镀层中SiC含量随着镀液中SiC含量的增加而增加,超过一定值(0.6 g/100 mL)增加幅度变小;超声波分散时间在10~50 min之间,镀层中SiC的含量随时间的增加而先增加后减少。镀层中碳化硅颗粒均匀分布有利于晶粒的细化。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

FORMULAS OF TENSION OF CONTINUOUS ROLLING PROCESS

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.     

RHEOLOGY FEATURE OF SIMPLE METAL MELT

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.