磁场约束下碳钢表面Ni-W合金电镀层的制备与性能

研究了施加稳恒磁场(0～1 T)对碳钢表面电镀Ni-W合金的影响。测定了不同方向、不同强度稳恒磁场下的电流效率、合金组成及镀层硬度,并用X射线衍射对镀层的微观结构进行了分析。对实验结果进行了分析讨论,找出了稳恒磁场对上述性能的影响规律。结果表明:与不施加磁场相比,施加磁场后镀层的含钨量上升:当磁场方向垂直于电场方向(B⊥J),B=1.0 T时,含钨量上升了约11%;当磁场方向平行于电场方向(B∥J),B=1.0 T时,含钨量上升了约13%;镀层的非晶化程度增强;镀层的硬度提高、孔隙率下降;但Ni-W合金电沉积的电流效率降低。     

一种制备纳米复合镀层的新方法

研究了一种制备纳米复合镀层的新方法--在直流电镀过程中对电镀液施加强磁场以代替机械搅拌来制备Ni/Al2O3纳米复合镀层,考察了镀层的结构,并对镀层性能进行了研究.结果表明,在强磁场下可以制得纳米复合镀层;与未加磁场的纯镍镀层相比,施加磁场后镀层的晶体结构发生了择优取向;当磁场强度为8T时,复合镀层的磨损率仅为纯镍镀层的25%,其耐蚀性与Q235钢相比提高56.3%,与纯镍镀层相比提高46.8%.强磁场对电镀液起到较好的搅拌作用,通过影响镀层中纳米微粒的含量,使镀层结构发生变化,进而影响镀层的性能.     

稳恒平行磁场对循环电镀液Fe-Si复合电沉积的影响

以不同硅含量的Fe-Si合金颗粒及纯Si颗粒为原料,在稳恒平行磁场下采用循环镀液复合电沉积法制备Fe-Si复合镀层,考察了磁场强度、颗粒硅含量、电流密度对Fe-Si复合镀层形貌及镀层中硅含量的影响。结果表明,在无磁场情况下,随着颗粒硅含量的增加,镀层中硅含量显著下降;施加平行磁场后,随着磁场强度的增加,Fe-50%Si(质量分数,下同)、Fe-70%Si和纯Si颗粒获得的镀层硅含量显著增加,而采用Fe-30%Si颗粒在磁场强度高于0.3 T后获得的镀层硅含量呈下降趋势。同时,在梯度磁场力和磁流体力学效应(MHD效应)协同作用下,Fe-Si颗粒在镀层表面呈圆丘状分布。当电流密度为2 A/dm~2、磁场强度为0.5 T时,采用Fe-50%Si颗粒电镀获得的镀层硅质量分数可达21.23%。     

电沉积钨合金镀层的研究现状与应用进展

介绍了电沉积钨合金镀层最常见的几种二元系、三元系及多元系合金类型,概述了在许多重要领域的研究和应用的现状与进展,分析了元素种类和含量对钨合金镀层硬度、耐磨性、耐蚀性和热稳定性等性能的影响,并详细探讨电镀工艺中镀液组成、温度、pH值、电流形式以及不同的热处理过程对钨合金镀层晶态与非晶态结构的影响,重点论述了钨合金镀层的耐蚀性与其晶体结构的关系,最后提出了今后钨合金镀层及其耐蚀性研究与应用的重要方向.     

ZLl01A合金化学镀Ni-P研究

为提高ZL101A合金的耐蚀性能,可直接化学镀Ni-P或电镀Cu后化学镀Ni-P在其表面施加镀层.利用恒电位仪、盐雾实验、扫描电镜和显微硬度计等,研究了两种工艺处理后镀层的性能.结果表明,两种工艺得到的镀Ni-P样品均具有优异的耐蚀性和较高的硬度,对Al合金基体都具有很好的保护作用;其中带镀Cu中间层的化学镀Ni-P层更致密,具有更好的耐蚀性和硬度.     

A356合金化学镀Ni-P工艺及其性能研究

用直接化学镀Ni-P和先电镀Ni后化学镀Ni-P两种方法在A356合金表面施加镀层.利用恒电位仪、盐雾实验、扫描电镜和显微硬度计等分析测试手段研究了两种工艺处理后镀层的性能.结果表明：两种不同工艺得到的镀Ni-P样品均具有优异的耐蚀性和较高的硬度,对Al合金基体均有很好的保护作用;其中带镀Ni中间层的化学镀Ni-P层更致密,具有更好的耐蚀性和硬度.     

合金化效应对Ni-W镀层微观组织和力学性能的影响

通过研究微量合金元素W(2.0at%)添加下,电沉积Ni-W镀层表面形貌、微观组织和力学性能的变化,探索了材料制备工艺与微合金化对改善Ni-W镀层组织、进一步提高力学性能的内在机制。结果表明,Ni-W镀层为单相fcc结构,随着W含量的增加,镀层表面从粗大的棱锥界面沟槽转变为均匀分布的微孔,同时表面粗糙度和晶粒尺寸逐渐减小,且镀层中Ni(220)衍射峰的强度也逐渐减弱;而镀层的屈服强度在1.0at%W含量左右发生突增,从约1.0 GPa增长到约2.0GPa,拉伸延伸率却没有明显变化。此外,Ni-W镀层具有比较稳定的应变硬化能力,基本不随合金元素含量而变化。本研究通过微合金化对表面缺陷和微观组织的调控,实现了低W含量Ni-W合金镀层的力学性能优化。     

电流密度对电镀铁-钨非晶合金镀层的影响

利用电镀技术在钢基体表面制备了铁一钨非晶合金镀层.采用SEM,EDS和XRD等方法分别研究了镀层表面形貌、成分和结构随电流密度的变化规律,获取了不同电流密度下的阴极电流效率、镀层厚度和显微硬度.研究表明:随着电流密度的增加,镀层颗粒和孔隙增大,且孔隙有增多的趋势,钨含量略有降低,阴极电流效率降低,镀层增厚且硬度降低.此外,还分析了电流密度的改变引起镀层形貌、钨含量、阴极电流效率、镀层厚度和硬度发生变化的原因.     

用改良静滴法测量液态Ni-W二元合金的密度

为了给研究合金在凝固过程中发生收缩、迁移现象和偏析提供科学依据,我们用改良静滴法对钨浓度为0到15%的液态Ni-W二元合金的密度进行了测量.结果表明Ni-W二元合金的液态密度随温度的增加而减少,但随合金中钨浓度的增加而增加;液态Ni-W二元合金的摩尔体积随温度和合金中钨浓度的增加而增加.金属钨在Ni-W二元合金中的偏摩尔体积约为(10.80-1.35×10-3T)×10-6m3·mol-1.     

Al—Mn非晶合金镀层

研究了在普通钢板上熔盐电解沉积ＡｌＭｎ非晶合金，通过实验确定了电解ＡｌＭｎ非晶合金的熔盐电解液，讨论了电流密度、电镀温度等参数对电流效率及ＡｌＭｎ非晶合金镀层的成分、结构、耐蚀性的影响。结果表明，当电流密度为２０～２５ｍＡ／ｃｍ２、镀液的ＭｎＣｌ２量在１．５％～３．５％、电解温度为１８０～２５０℃时，可以得到表面光亮度及耐蚀性均好的ＡｌＭｎ非晶合金镀层     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.