阴极平动式摩擦辅助精密电铸的研究

为了实现非回转体类零件的精密电铸成形,提高电铸层的质量和电铸速度,文章提出了阴极平动式摩擦辅助精密电铸,在电铸液中充满陶瓷微珠等一类硬质粒子,阴极在平动机构的驱动下做平动,使硬质粒子不断摩擦和撞击阴极表面.通过对金属镍的电铸实验表明:阴极平动式摩擦辅助精密电铸能很好地去除沉积层表面的针孔、麻点等缺陷,获得的电铸层外表面Ra值达到0.016 μm.阴极平动式摩擦辅助精密电铸能有效地改变电铸层的组织结构,细化晶粒,提高电铸层的机械性能.     

精密微成型双缸电铸装备的研制

随着MEMS(微机电制造系统)技术的发展和各种异型、复杂精密微细零件制造的需要,作为精密加工制造技术的精密电铸技术越来越受到人们的关注。由于电铸技术存在表面质量缺陷多、加工效率低的缺点,使得电铸技术的发展受到严重阻碍。设计了机电一体的电铸成型装备,采用双缸结构,能够成倍地提高电铸加工效率;两工作阴极分别采用旋转和双轴联动的多路径移动方式对铸液进行搅拌;采用PLC和A/D转换模块,可实时在线控制温度和检测pH值,能更好地改善电铸成型质量。     

微模具电铸成型工艺研究

针对微细电铸成型技术中微流道模具的铸层均匀性、铸层气孔和表面粗糙度等工艺问题,提出了控制成型过程中阴极电流密度、增加辅助阴极和阴极平动的方法。通过正交实验对基底蚀刻深度、光刻掩膜厚度、电铸槽温度和阴极电流密度等因素进行工艺优化研究。结果表明,得到最佳工艺参数为阴极电流密度4 A/dm~2、二次辅助阴极电流密度1.5 A/dm~2,阴极平动速率0.01 m/s,温度50℃、掩膜厚度50μm、刻蚀深度20μm。获得了尺寸均匀性好、铸层气孔少,表面粗糙度为Ra 0.5μm的微模具。     

选择性电铸扫描轨迹的研究

选择性电铸是将快速成形技术与电铸结合在一起而形成的一种新的快速成形方法,在讨论快速成形制造技术切片算法的基础上,介绍如何将三维实体的STL文件变成选择性电铸中的喷嘴分区连续扫描轨迹,以满足选择性电铸的特殊工艺要求。     

辅助磨擦对镍电铸层力学性能的影响

在磨擦辅助电铸镍过程中,通过改变游离微珠对电铸层表面的磨擦强弱,制备不同力学性能的镍电铸层。对所制备镍电铸层的表面形貌、织构等微观结构和显微硬度、抗拉强度及伸长率等性能进行测试和分析。结果表明:采用卧式放置的阴极能制得材料组织结构均匀的电铸层。且随着阴极表面线速度的提高,游离微珠对电铸层的整平作用和晶粒细化作用增强。在不同线速度下采用旋转阴极可以制备大范围力学性能的镍电铸层,其表面粗糙度为0.15~0.03μm、硬度为185~410HV、抗拉强度为525~1 020 MPa、伸长率为24%~4%。     

基于增材制造的旋印电解加工工具阴极制备

工具阴极的制备直接影响旋印电解加工的成形质量,尤其对于阵列凸台回转体工件的倍转速旋印电解加工,采用传统机械加工难度大,且难以解决窗口侧壁绝缘问题.针对这一难题,综合运用增材制造及电铸技术,提出一种基于增材制造的工具阴极制备方法,通过仿真和试验对电铸生长过程开展研究.结果表明:在侧壁绝缘条件下铸层均匀性良好,工具阴极能满...     

高精度矩形弯铜波导管加工研究

高精度矩形弯铜波导管一直采用制造周期长的电铸加工而成,为了寻求快速的制造方法,进行了系列的模具压制成形实验,改变了凸模结构,改进了成形工艺,快速地制造出合格的产品。     

高速电铸工具制造技术的开发

为了利用电铸层作为微型磨具，开发出两种可制备厚电铸层的电铸工艺。立式低速搅拌法是以低速连续搅拌，在阴极沉降磨粒，以提高阴极附近的镍离子密度。卧式低速旋转法则是试图在被覆圆柱形阴极的丙烯盖上设置3mm见方、长15mm的槽，通过低速旋转阴极让电铸层沿着槽生长。使用立式低速搅拌法时，由于电力线集中在阴极外周，电铸层厚度欠均匀。卧式低速旋转法可在18．3小时内制备出3mm见方、长15mm的电铸层。     

发展中的电铸技术

简述了电铸的原理及方法，介绍了在传统应用场合电铸技术进一步的研究成果，以及电铸技术在微器械、快速成形等高新技术领域内的研究和应用成果。     

复杂型面电铸不溶性组合阳极优化设计

提出了一种电铸阳极优化设计方法,采用多个不溶性阳极单元组合成阳极轮廓,通过调整各阳极单元与阴极表面上各对应点的间距,以及对特殊部位进行局部修正,使阴极表面电场分布的均匀性得到改善。利用该方法对喷管模拟件的电铸阳极进行设计,结果表明,阴极各点电场强度最大与最小比值从2.19减小到1.15。     

精密铸造与电解铸造在首饰制作工艺中的比较分析

对首饰制作中精密铸造和电解铸造工艺的特点进行了分析和探讨。与精密铸造相比,电解铸造所制作出的首饰具有金属层薄、质量轻、成本低等优点,但由于通过阴极和阳极的电流强度不同,造成电解铸造的金属厚度不同。精密铸造工艺是目前国内外首饰生产企业,进行批量化生产所采用的成熟工艺方式。     

Production of Polymer Matrix Composite Coatings by Thermal Spraying

The production of ceramic-polymer and metal-polymer matrix composite coatings by plasma spray deposition has been studied. The work involves the co-deposition of alumina, magnesium hydroxide, silica and stainless steel with nylon by simultaneous powder injection into the plasma jet. The results show that dense deposits with sound bonding between the filler particles and the matrix can be produced. The deposition efficiency of the filler decreases with increasing particle size and density due to particle rebound from the underlying coating layers and substrate during spraying. No significant deterioration in coating-substrate adhesion of the composite coatings relative to the equivalent pure nylon was found owing to the formation of a denuded interfacial layer and the enhanced integrity of the deposit. The composite coatings showed major improvements in abrasive and adhesive wear resistance due to particle-strengthening and reduced contact between nylon and the counterface at the sliding interface.     

Development of a micro diamond grinding tool by compound process

This study presents a novel micro-diamond tool which is 100 μm in diameter and that allows precise and micro-grinding during miniature die machining. A novel integrated process technology is proposed that combines “micro-EDM” with “precision composite electroforming” for fabricating micro-diamond tools. First, the metal substrate is cut down to 50 μm in diameter using WEDG, then, the micro-diamonds with 0–2 μm grain is “plated” on the surface of the substrate by composite electroforming, thereby becoming a multilayer micro-grinding tool. The thickness of the electroformed layer is controlled to within 25 μm. The nickel and diamond form the bonder and cutter, respectively. To generate good convection for the electroforming solution, a partition designed with an array of drilled holes is recommended and verified. Besides effectively decreasing the impact energy of the circulatory electroforming solution, the dispersion of the diamond grains and displacement of the nickel ions are noticeably improved. Experimental results indicate that good circularity of the diamond tool can be obtained by arranging the nickel spherules array on the anode. To allow the diamond grains to converge toward the cathode, so as to increase the opportunity of reposing on the substrate, a miniature funnel mold is designed. Then the distribution of the diamond grains on the substrate surface is improved. A micro-ZrO₂ ceramic ferrule is grinded to verify the proposed approach. The surface roughness of R_a = 0.085 μm is obtained. It is demonstrated that the micro-diamond grinding tool with various outer diameters is successfully developed in this study. The suggested approach, which depends on machining applications, can be applied during the final machining. Applications include dental drilling tools, precision optic dies, molds and tools, and biomedical instruments.     

游离粒子对摩擦辅助电铸技术的影响

摩擦辅助电铸技术是采用不添加任何添加剂的标准电铸液,在阴阳极之间添加不导电的游离粒子,在电铸过程中运动的阴极带动游离粒子不断摩擦、挤压电铸层,可得到外观表面平整、光亮、无任何麻点、针眼、结瘤等缺陷的电铸层,其机械性能也非常优异.游离粒子在电铸过程中起到了至关重要的作用.选用不同直径的硅酸锆球,作为新工艺的摩擦介质,通过对比试验方法来研究游离粒子的直径对电铸层表面形貌、微观组织和机械性能的影响规律.试验结果表明,在摩擦辅助电铸过程中,游离粒子的直径对电铸层外表面质量影响非常明显.粒子直径过小,电铸工艺处于亚复合电铸状态,易造成电铸层起皮;直径太大,易导致电铸层摩擦不均匀;当粒子直径在0.4～2.0 mm之间时,能获得表面光亮、平整和强度较高的电铸层.     

复合电铸制备Cu/SiCp复合材料

采用复合电铸工艺制备碳化硅颗粒(SiCp)增强铜基复合材料,研究了镀液中颗粒浓度、镀液温度、电流密度对Cu/SiCp复合材料中SiCp含量的影响.通过优化各工艺参数可有效促进SiCp与铜的共沉积,提高复合材料中增强固体颗粒的含量.结果表明:随着SiCp含量增加,Cu/SiCp复合材料的热膨胀系数和导热系数减小,抗弯强度和硬度提高.此外,复合电铸工艺制备的复合材料具有较大内应力,对Cu/SiCp复合材料的热膨胀性能和硬度有一定影响.     

多功能数控电铸机床的研制

针对现有电铸机床存在的不足,开发出一种电极布局方式多变、电极自动运动模式多样、电铸工艺参数实时在线监控、应用场合广泛的多功能数控电铸机床。重点介绍了该机床的电沉积模块、循环过滤模块、数控模块等主要功能模块的组成、功用及结构特点。     

Corrosion Studies on Electrodeposited Nickel-Manganese Coatings

The effects of several plating variables, current density (CD), bath composition and additives on the corrosion properties of electrodeposited Ni-Mn coatings on mild steel have been investigated in 3% NaCl. Results indicate that the plating variables have marked effects. With different additives, the crystal growth pattern is altered resulting in different corrosion characteristics. γFe₂O₃.H₂O,γ FeOOH and ferrihydrate form the major phases in the corrosion products. Five plating conditions are identified giving suitable Ni-Mn deposits to function as sacrificial coatings for mild steel. Benzene, as additive, is helpful in increasing the Mn content in the deposit.     

镍-氧化锆纳米复合电铸层微观形貌影响因素的分析

用SEM分析了诸如电铸时间、电流密度、镀液中纳米ZrO2颗粒悬浮量、电流形式和阴极表面粗糙度等因素对Ni-ZrO2纳米复合电铸层微观形貌的影响.结果表明,电铸时间、阴极电流密度以及镀液中纳米ZrO2悬浮量对纳米复合电铸层微观形貌有一定程度的影响,采用脉冲电沉积工艺有助于获得表面光滑平整、显微组织均匀致密的纳米复合电铸层.