共查询到20条相似文献,搜索用时 171 毫秒
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铬镀层的硬度高,耐磨性好,而且可以在高温下工作,可以广泛地用于需要耐磨的零件和工具、量具、模具,以及修复零件的尺寸.针对硬铬镀层厚度不均匀的问题,通过对电镀铬层电导率、电流密度、槽液温度、槽液循环、电流效率等因素的研究,分析各要素对零件电镀铬层均匀性的影响,指出合理的电流密度为-3000~-6000 A/m2,电镀温度... 相似文献
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采用电泳-电沉积技术制备了纳米Al2O3增强镍基复合镀层,并采用扫描电镜及其附带能谱仪分析了镀层中纳米颗粒的分布状态,运用正交试验法研究了电泳液中纳米颗粒含量、电泳沉积电压、电泳沉积时间以及电沉积阴极电流密度等工艺参数对复合镀层中纳米颗粒分布均匀性的影响.结果表明:电泳液中纳米颗粒含量及电沉积阴极电流密度是影响镀层中纳米颗粒分布均匀性的主要因素,而电泳沉积电压和电泳沉积时间的影响相对较小;在电泳液中A12O3纳米颗粒含量为8 g·L-1、电沉积阴极电流密度为0.5 A·dm-2时,可制得纳米颗粒均匀分布的纳米复合镀层. 相似文献
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铝合金表面电沉积Ni-SiC复合镀层的研究 总被引:6,自引:0,他引:6
针对铝合金表面的电镀特点,采用化学侵锌、预镀镍等预处理方法,在铝合金表面得到了表面光洁平整,内部质量优良,与铝合金基体结合紧密的Ni-SiC复合镀层。研究了镀液中SiC浓度、电流密度、搅拌速度、镀液pH值和镀液温度等电镀参数对复合镀层厚度、镀层中的SiC体积分数及镀层显微硬度的影响。结果表明,电镀工艺条件的改变影响Ni-SiC复合镀层的共沉积速度与SiC粒子在镀层中的体积分数。当镀液SiC浓度为120g/L时,镀层中的SiC体积分数为8.5%,硬度为504.6HV,较纯铝(82.5HV)提高5倍,较纯镍(242.5.HV)提高l倍。 相似文献
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张菊生 《机械工业标准化与质量》2002,(7):32-33
为了防止黑色金属零件的锈蚀,经常采用电镀一层金属或发蓝来进行表面处理。常用的电镀方法有镀锌、镀镉和镀铬。表面处理后,可以提高零件的使用寿命并使外形美观。 图1是我厂生产的耳片的产品图样,它的2×φ6H11(07500.+)mm是要求镀后达到的尺寸。该零件的表面处理为镀锌,镀层厚度为5~12μm。要达到镀后φ6H11 mm的要求,就必须预留出镀层厚度,这样在镀后才可达到图样的尺寸要求。按照图样的最大极限尺寸镀最薄的镀层厚度、最小极限尺寸镀最厚的镀层厚度的原则,这个零件两孔的镀前尺寸应为: 最大极限尺寸=6.075+0.005×2=6.085 mm… 相似文献
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罗来康 《机械工人(热加工)》1984,(2)
镍铁合金电镀工艺近年来有较大发展,并得到了广泛的实际应用。实践证明,镀层为含铁20~45%的光亮镍铁合金,其性能与亮镍镀层相同,甚至更好;尤其是用铜或黄铜打底,含铁量为20~45%的合金镀层,厚度小于12.7微米(如2.54微米)时,其效果比用同样厚度的亮镍镀层更好。为了节约更多的金属镍,目前各国都在努力研究把镍铁合金镀层中的铁含量提高到最大值。国内最近的研究成果表明,在以镍铁合金电镀液为基的复合电镀工艺中 相似文献
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Nanocomposite coatings can endow a plated surface with various properties such as wear resistance, high-temperature corrosion protection, oxidation resistance, and self-lubrication. This work studies the corrosion and corrosive wear resistance of electroplated nickel nanocomposite coatings on Ti-6Al-4V alloy in a Hank's solution, adding various concentrations of an Al2O3 powder in plating solution, with particle diameters of 20–30 nm and 1 μm for comparisons. The experimental results showed that the content of Al2O3 incorporated into the electroplated nickel composite coating increased with the concentration of Al2O3 powder in the electroplating solution, and increasing the surface hardness, corrosion, and corrosive wear resistance of electroplated nickel micro- and nanocomposite coatings caused smearing of the nodule boundary and elimination of voids in the deposits. The Al2O3 nanoparticulates were embedded and distributed more uniformly than the Al2O3 microparticulates in the nickel matrix after a heat treatment of 400°C, producing a more continuous and dense coated composite layer on the Ti-6Al-4V substrate. This phenomenon is responsible for the Ni/Al2O3 composite coating with superior surface hardness, providing high corrosion resistance and corrosive wear protection to the Ti-6Al-4V alloy substrate in Hank's solution. 相似文献
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用表面活化技术提高金刚石与镀层的结合性能 总被引:1,自引:0,他引:1
分别用活化处理和未活化处理的金刚石磨粒制备了电镀金刚石工具,通过扫描电子显微镜观察金刚石与镀层的结合状况。对氧化铝陶瓷材料进行钻削加工,对比电镀金刚石钻头在耐用度期间的陶瓷材料去除体积。结果表明,经活化处理的金刚石表面沉积分散的钯质点,工具电镀过程中,在金刚石与镀层间的结合面上形成分散的连接点。应用表面活化技术制作电镀金刚石工具,可使金刚石与镀层形成牢固连接,改善镀层与金刚石的结合性能,其氧化铝陶瓷材料去除体积是未经活化处理金刚石电镀钻头的1.5倍,明显提高了电镀金刚石工具的磨削性能和使用寿命。 相似文献
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Mild steel specimens electroplated with nickel and with Ni-Co alloys were tested under conditions of fretting fatigue. A nickel electrodeposit 25 μm thick with an internal compressive stress of 61.8 MN m?2 and with a hardness of 355 HV30 produced the best result; an improvement of 58.5% was observed in the fretting fatigue limit. All the electrodeposits were prepared from a concentrated nickel or Ni-Co sulphamate electrolyte. 相似文献
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In this paper, we report the detailed investigation into the effects of plating temperature and applied current density upon
the mechanical properties of plated nickel film such as Young’s modulus and residual stresses. This method uses the resonance
method of atomic force microscope, which does not require specially microfabricated cantilevers and additional experimental
set-up. Thin layers of nickel are electroplated onto the tip surface of AFM cantilevers and plating thicknesses were measured
at the end of each plating step. The self-deformation of the released AFM cantilever is also measured as a function of the
plated nickel thickness, which is converted into the quantitative residual stress by appropriate mechanics. The measured Young’s
modulus is as high as that of bulk nickel at low plating temperature and at low applied current density, but drastically drops
at high temperature or current density. The dependence of Young’s modulus on the plating thickness is negligible in thin film
less than few microns. The residual stress is also a strong function of the process conditions, and decreased with the elevation
of the current density and plating temperature. And the intrinsic and extrinsic stresses of plated nickel are separated from
the measured residual stress, and correlated with plating conditions. Dependence of the plated thickness on Young’s modulus
and residual stress is also considered. 相似文献
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Soft steel and aluminium substrates with load-carrying layers of electroplated nickel were coated with commercially available low friction vapour deposited coatings. The mechanical and tribological properties of the coating and substrate composites were evaluated with special emphasis on the influence of the nickel layer. Two different thicknesses of the intermediate load-carrying nickel layer were tested. The samples were evaluated regarding friction and sliding wear, abrasive wear, hardness and elastic modulus, morphology and coating thickness and adhesion between substrate and coating. It was found that all the evaluated low friction coatings were possible to be successfully deposited on the intermediate nickel layer. A relatively thick intermediate nickel layer is a promising candidate for improvement of the load-carrying capacity. 相似文献
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Hongxiu Zhou Shuo Qiu Yanxia Huo Nianmin Zhang 《The International Journal of Advanced Manufacturing Technology》2013,66(5-8):947-953
High-speed dicing tests were conducted for silicon wafers using developed ultrathin electroplated diamond blades with metal bond. Chipping and kerf widths of 1.5 and 28 μm, respectively, are achieved by the developed ultrathin diamond blades. The calculated maximum undeformed chip thickness varied from 9.6 to 25.5 nm for various high-speed dicing conditions. The variation tendency between experimental chip width induced by three diamond blades and corresponding calculated maximum undeformed chip thickness is consistent. Scanning electron microscopy showed that the microstructure of diamond dicing blades significantly affected the chip width. 相似文献
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采用脉冲电沉积工艺制备了厚度为0.1mm的纳米镍薄板,在不同的温度和应变速率下对该薄板进行单向拉伸试验,确定了其超塑性变形的最佳工艺条件,在此基础上进行了纳米镍薄板的微拉深性能实验。实验结果表明:纳米镍薄板的微拉深性能随成形温度的升高而提高;在温度为723K、半球形拉深凸模直径为1mm、拉深速度为1~5mm/min的条件下,均可成功拉深出半球件。采用透射电镜和扫描电镜对拉深变形前的沉积态组织和拉深变形后的微观组织进行了观察比较,结果表明,微拉深后大部分镍晶粒长大到微米量级。根据实验结果,初步探讨了超塑微拉深的主要变形机制。 相似文献
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