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电火花技术和溶液中的电化学沉积,以及随后退火的工艺,均适用于钛、铬和不锈钢的表面合金化涂层。已发现表面合金化有效地取代了整体添加合金元素的方法。钛、铬和不锈钢表面钯合金化大大地改善了在硫酸和盐酸中的抗腐蚀性能。 相似文献
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利用激光表面合金化技术以铜粉为初始原料,在纯钛表面通过激光表面合金化原位反应成功制备了Ti-Cu纳米晶金属间化合物涂层。采用X-射线衍射仪(XRD)和高分辨透射电镜(HRTEM)分析了涂层的组成和组织结构,测试了涂层在不同载荷下的摩擦磨损性能。结果表明:通过激光表面合金化制备的涂层主要成分为Ti和金属间化合物TiCu、TiCu3、Ti3Cu相。涂层含有纳米晶Ti-Cu金属间化合物,晶粒尺寸为10~500nm。Ti-Cu金属间化合物涂层的摩擦因数随载荷增加而减小,体积磨损率在10-6~10-5 mm3/Nm数量级范围并随载荷的增加而增大,与纯钛底材相比,Ti-Cu金属间化合物涂层具有良好的耐磨性。 相似文献
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电子束表面合金化技术能够赋予材料优异的表面性能,其制备低成本和高性能的技术特点使其在民用和军工领域具有广阔的应用前景.总结了电子束表面合金化技术原理及特点,综述了国内、外涂层电子束熔覆技术的研究现状和最新进展,着重介绍了电子束熔覆工艺对改性层组织及性能的影响,并对目前存在的问题及未来发展方向作了简要的论述. 相似文献
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《机械制造文摘:焊接分册》2010,(2):43-47
电子束表面合金化技术能够赋予材料优异的表面性能,其制备低成本和高性能的技术特点使其在民用和军工领域具有广阔的应用前景。总结了电子束表面合金化技术原理及特点,综述了国内、外涂层电子柬熔覆技术的研究现状和最新进展,着重介绍了电子束熔覆工艺对改性层组织及性能的影响, 相似文献
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采用自行研发的同步送粉式直流放电压缩电弧等离子束表面冶金技术,利用不同粒度、不同密度、不同形状的混合粉末颗粒,在普通低碳钢表面获得了工程厚度的均匀致密的铁基合金涂层.利用OM、SEM、EDS、EMPA及XRD法研究了该合金化涂层的显微组织、物相组成、溶质分布及基材热影响区的凝固组织特征.结果表明,等离子表面冶金合金化涂层对基材具有良好的润湿性,基材表面熔化区的形成使得涂层与基材实现了完全的冶金结合.快速凝固合金化涂层具有分层凝固特征,从底部具有外延生长的平面晶到中部近等轴晶及表层的穗状晶.凝固组织为固溶了大量Cr及少量B、Si的极度过饱和的γ-(Fe,Ni)枝晶及枝晶间合金硼碳化物(Cr,Fe)7(C,B)3与γ-(Fe,Ni)共晶组织的复相组织. 相似文献
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Cupronickel was used as the electrode material to fabricate microstructures on polycrystalline diamond by electrical discharge machining (EDM). The electrodes were shaped into tiny rotary wheels driven by the flow of EDM fluid. Results showed that material removal rate was improved by a factor of five compared to conventional electrode materials. Raman spectroscopy and energy dispersive X-ray spectroscopy indicated that graphitization of diamond and diffusion-based chemical reactions between nickel and diamond dominated the EDM process. Effects of electrode rotation rate and discharge energy on the EDM characteristics were clarified. High form accuracy (∼0.5 μm/1 mm) and low surface roughness (∼0.1 μm Ra) were obtained. 相似文献
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目的 分析液相脉冲放电微观机理,解释放电过程中放电通道对电极的影响。 方法 以 45 钢表面液相脉冲放电沉积 TiC 陶瓷涂层放电沉积瞬间极板间形成的单脉冲等离子体为研究对象,用粒子模拟的方法描述了放电通道中电子、钛离子的运动及分布状态。 结果 放电通道中电子的运动较为活跃,在放电形成的开始阶段,电子由工件电极负极激发,迅速向工具电极移动,期间通过与液相介质中的中性粒子碰撞,迅速往工具电极积累,运动过程中遵循等离子体的集体运动特性,过程贯穿于整个等离子体的形成过程;在相同的时间步长内,放电通道中 Ti 离子的运动比电子要缓慢得多,在脉冲放电期间需要较多的时间才能迁移到极板。 结论 放电镀膜时,所用极间距应大于电火花成形加工时的极间距。 相似文献
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电火花摇动加工微细阵列轴和孔的试验研究 总被引:1,自引:0,他引:1
针对微细阵列轴和孔的电火花加工,提出了利用数控电火花加工机床摇动功能的摇动加工微细阵列轴和孔的方法.此法是基于电火花反拷贝加工的原理,先用丝电极在薄平板(中间电极)上按要加工的阵列轴和孔间距或数倍间距加工阵列小孔(直径0.1 mm以上),然后用加工的薄平板(中间电极)作电极,电火花摇动加工微细阵列轴(电极),最后用此微细阵列电极加工阵列孔.进行了电火花摇动加工微细阵列电极试验,得到了单电极直径为50 μm、长径比为16的3×3阵列电极,并用此电极在70 μm厚的不锈钢板上加工出单孔直径为70 μm的3×3微细阵列孔.试验结果表明,电火花摇动加工方法可实现微细阵列轴和孔的加工. 相似文献
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Apiwat Muttamara Yasushi Fukuzawa Naotake Mohri Takayuki Tani 《Journal of Materials Processing Technology》2003,140(1-3):243-247
Electrical discharge machining (EDM) is used as a precision machining method for the electrically conductive hard materials with a soft electrode material. But recently we succeeded to machine on insulating material by EDM. The technology is named as an assisting electrode method. The EDMed surface is covered with the electrical conductive layer during discharge. The layer holds the electrical conductivity during discharge. For micro-EDM, the wear of tool electrode becomes lager ratio than the normal machining. So the micro-machining is extremely difficult to get the precision sample.
In this paper to obtain a fine and precise ceramics sample, some trials were carried out considering the EDM conditions, tool electrodes material and assisting electrode materials. Insulating Si3N4 ceramics were used for workpiece. The machining properties were estimated by the removal rate and tool wear ratio. To confirm the change of micro-machining process, the discharge waveforms were observed. The micro-machining of the Ø0.05 mm hole could be machined with the commercial sinking electrical discharge machine. 相似文献
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This paper describes improvement of the machining characteristics of dry electrical discharge machining (dry EDM) by controlling the discharge gap distance using a piezoelectric actuator. Dry EDM is a new process characterized by small tool electrode wear, negligible damage generated on the machined surface, and significantly high material removal rate especially when oxygen gas is used. However, the narrow discharge gap length compared with conventional EDM using oil as the dielectric working fluid results in frequent occurrence of short circuiting which lowers material removal rate. A piezoelectric actuator with high frequency response was thus introduced to help control gap length of the EDM machine. To elucidate the effects of the piezoelectric actuator, an EDM performance simulator was newly developed to evaluate the machining stability and material removal rate of dry EDM. 相似文献
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Electrical discharge machining (EDM) is one of the most widely disseminated manufacturing technologies, in particular as regards the generation of accurate and complex geometrical shapes on hard metallic components. Nevertheless current EDM technologies have major limitations when dealing with fine surface finish over large process area. Indeed this is one reason that explains the need of final manual polishing of mould cavities performed by EDM. Recently EDM with powder-mixed dielectric (PMD-EDM) has been a focus of an intense research work in order to overcome these technological performance barriers. This paper presents a research work within the objective to acquire deep knowledge on EDM technology with powder mixed dielectric and to compare its performance to the conventional EDM when dealing with the generation of high-quality surfaces. In particular the analysis of the effect of the electrode area in the surface quality measured by the surface roughness and craters morphology was carried out for both technologies. The results achieved evidenced a linear relationship between the electrode area and the surface quality measures as well as a significant performance improvement when the powder mixed dielectric is used. 相似文献
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Masahiro FujikiGap-Yong Kim Jun NiAlbert J. Shih 《International Journal of Machine Tools and Manufacture》2011,51(1):77-83
A new gap control strategy for five-axis milling using near-dry electrical discharge machining (EDM) has been experimentally investigated. The conventional EDM control strategy only allows the retraction of the electrode in the direction of machining trajectory, which results in inefficient gap control when the electrode is not perpendicular to the workpiece. The new gap controller is capable of retracting the electrode in the direction of its orientation. This enables more efficient enlargement of the discharge gap leading to faster recovery of average gap voltage. Experimental results show a 30% increase in material removal rate while the tool electrode wear ratio and surface roughness are not affected. Furthermore, EDM efficiency is improved due to the change in the electrode retraction in its axial direction. The gain tuning of the proposed controller is also discussed. This study shows the direction of electrode retraction is important for five-axis near-dry EDM milling. 相似文献
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Norliana Mohd Abbas Darius G. Solomon Md. Fuad Bahari 《International Journal of Machine Tools and Manufacture》2007,47(7-8):1214-1228
Electrical discharge machining (EDM) is one of the earliest non-traditional machining processes. EDM process is based on thermoelectric energy between the work piece and an electrode. A pulse discharge occurs in a small gap between the work piece and the electrode and removes the unwanted material from the parent metal through melting and vaporising. The electrode and the work piece must have electrical conductivity in order to generate the spark. There are various types of products which can be produced using EDM such as dies and moulds. Parts of aerospace, automotive industry and surgical components can be finished by EDM. This paper reviews the research trends in EDM on ultrasonic vibration, dry EDM machining, EDM with powder additives, EDM in water and modeling technique in predicting EDM performances. 相似文献