工艺参数对连续碳纤维表面电磁搅拌化学镀镍的影响

目的解决连续碳纤维在镀覆过程中易出现黑心现象以及无法完全浸泡于镀液中的问题,制备镀层均匀的连续碳纤维镍镀层。方法引入外加电磁搅拌对连续碳纤维进行化学镀镍,研究了施镀时间、镀液温度、镀液pH值以及电磁搅拌转速对连续碳纤维表面微观形貌及镀层沉积速率的影响规律。结果当搅拌转速一定时,随着施镀时间、镀液温度、镀液pH值的不断增加,碳纤维表面镀层逐渐变得均匀完整,且镀层厚度逐渐增大。但当施镀时间超过20 min,镀液温度超过75℃,镀液pH值超过8时,镀层表面沉积了大量形状不一的胞状镍颗粒,形成粗糙的表面形貌。镀层的沉积速率随着镀液温度、镀液pH值的升高而增大。当搅拌转速由200 r/min增加到300 r/min时,镀层的沉积速率随着搅拌转速的增加而不断增大;当搅拌转速由300 r/min增加到400 r/min时,镀层的沉积速率随着搅拌转速的增加而不断减小。结论电磁搅拌辅助连续碳纤维化学镀镍的最佳施镀工艺参数为:施镀时间15~20 min,镀液温度75℃,镀液pH为8,搅拌转速200~250 r/min。采用此工艺参数能获得表面致密、均匀完整的镍镀层。     

pH值对中温化学镀镍-磷的影响

化学镀镍-磷技术作为表面强化的一种途径,已经得到越来越广泛的应用和不断的发展.为了研究pH值对镀层性能的影响,采用中温化学镀镍工艺,以醋酸钠为缓冲剂,以乳酸为络合剂,在酸性体系中化学沉积镍-磷合金.研究了溶液的pH值对化学镀镍-磷合金的沉积速度、镀层性能的影响.结果表明:pH值对镀速的影响较大,随着pH值的升高,镀速逐渐增加,镀层磷含量逐渐降低;在一定范围内硬度和腐蚀速度随pH值的升高而增加,在pH值为5.1时,镀层的综合性能达到最好.     

环氧树脂表面化学镀镍层制备及结合力评价

采用化学镀的方法在环氧树脂表面制备镍镀层。观察了镀层表面和横截面形貌,研究了温度对镀层的表面形貌、沉积速率和结合力的影响,以及镀液pH值对镀层质量和沉积速率的影响,并对镀层与基体的结合力进行了评价。结果表明,环氧树脂化学镀镍的沉积速率随温度的升高而增大,但温度不宜太高,温度太高会增大镀层内部应力,降低镀层结合力。最佳施镀温度为35℃,镀液的最佳pH值为10,制备的镀层表面平整、均匀致密,镀层沉积速率为12μm/h,镀层与基体的结合力可达22.06 N。     

一种新型的碳纤维和碳纳米管化学镀镍工艺

碳纤维是最重要的复合材料增强体之一,而碳纳米管比碳纤维具有更好的力学性能,对他们的表面改性将会对复合材料性能有很大影响。试验实现了一种对碳纤维和碳纳米管通用的化学镀镍工艺。通过对基体较好的预处理,在基体上成功地完成了化学镀镍并且较好的控制了镀层成分。同时还探讨了施镀温度、pH值和搅拌方式等对镀层的影响,试验发现pH值控制在9~10之间,温度控制在70℃附近并采用氮气搅拌可以获得较满意的施镀效果。     

黄铜基体上化学镀镍的研究

研究了在黄铜基体上化学镀镍提高零件表面硬度的可行性,结果表明,使用恰当活泼金属与黄铜接触诱发化学镀镍反应,可以在NiSO4-H2PO2^-体系中实现黄铜表面的化学镀镍过程。通过正交实验优化了黄铜表面化学镀镍的镀液配方,探讨了pH值、温度等参数对镀速的影响以及热处理对镀层硬度的影响。镀后通过300－500℃热处理使零件的表面硬度达到900－950HV,镀层表面变为柔和光亮的棕黄色。     

光纤光栅表面化学镀镍及影响镀层性能的因素

目的通过优化化学镀工艺,在光纤光栅表面获得综合性能优良的镀镍层。方法利用化学镀置换还原反应,在非金属表面沉积金属镀层。改变镀镍液温度、pH值并优化敏化活化处理,得到连续光滑的镍层。通过金相显微镜对镀层进行形貌观测,用高低温交变试验箱和万能试验机对镀层附着力和镀镍后光纤光栅的抗拉力进行测试。结果与未优化时沉积镍层对比,优化化学镀工艺沉积的镍层连续光滑,说明镀液稳定干净,镍原子沉积速率合理。优化条件为:过滤敏化液和活化液,并在敏化、活化后各进行超声清洗30 s,镀镍液温度92℃,pH值3.2。该条件下可得到稳定干净的镀液和连续光滑的镀层。经测试,镀层无开裂脱落,镀镍光纤光栅的抗拉力在5.5 N以上。而未优化时,镀液不稳定,镀层不连续或连续部分不光滑,且超声清洗时部分脱落。结论优化化学镀工艺中敏化活化处理和镀镍液温度、p H值后,镀液干净稳定,镍原子沉积速率合理,所得镀层连续致密、厚度均匀,从而力学性能得到改善。     

碳纤维化学镀镍工艺参数的优化研究

研究了镀液pH值、施镀温度及施镀时间等工艺参数对碳纤维化学镀镍层厚度的影响，并研究了施镀时间与镀镍碳纤维导电性之间的关系，最终得出了较理想的碳纤维化学镀镍工艺参数。结果表明，采用优化后的工艺参数施镀，所得镀镍碳纤维镀覆均匀、光泽性好、镀层结合力强，导电性显著提高。     

碳纤维的化学镀镍

提出一种碳纤维的化学镀镍技术,研究了镀层的形成过程和显微组织。结果表明:用化学镀技术在碳纤维表面镀镍是成功的,镀层均匀连续。当镀层厚度小于0.3μm时,在碳纤维表面呈不连续分布的镍膜,大于0.8μm时,在连续分布的镀层上镍以枝晶状沉积出现。应用镀镍碳纤维制造的铝基复合材料,没有观测到明显的界面反应。     

化学沉积 Ni-P-荧光粉复合镀层及其性能研究

目的以铜合金为基体,采用化学镀技术制备Ni-P-荧光粉复合镀层。方法在化学镀镍液中加入荧光粉微粒,在不同条件下施镀,并对不同工艺参数下获得的镀层的表面形貌、结构和荧光特性进行研究。结果化学沉积Ni-P-荧光粉复合镀层的沉积方式为颗粒堆积,镀液中荧光粉的浓度和镀液的pH值对镀层中荧光粉的含量有影响。荧光粉微粒的加入使得镀层表面色泽变暗,外观较粗糙。对复合镀层进行荧光分析发现,激发光谱在激发波长450~560 nm范围内存在荧光峰,发射光谱在发射波长420~500 nm范围内存在荧光峰。结论采用合理的工艺参数可以获得Ni-P-荧光粉复合镀层,且镀液pH=5.0时,荧光效果最佳。     

飞机结构铝合金直接化学镀Ni-P合金研究

高强度铝合金被广泛用于飞机结构中，然而，这一系列铝合金抗腐蚀和耐磨性差，限制了其应用。而Ni-P合金镀层具有高的硬度和抗腐蚀性能等优异特点，成为增强表面性能的常用手段。采用化学镀镍工艺在铝合金（6061）表面进行化学镀镍处理，研究了pH值、沉积温度和沉积时间对沉积速率的影响。分析了化学镀镍层的成分和组织形貌，同时对镀层的硬度、抗腐蚀性进行了表征。试验表明，在铝合金表面化学镀镍可以显著提高铝合金表面的硬度，并改善其在5％NaCl溶液中的耐蚀性。     

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.     

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.     

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous network.Compared with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.     

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.