Ni-W基纳米复合镀层的制备及性能研究
发布时间：2018-07-14 22:32
【摘要】：性能优异、制备工艺简单的镍-钨(Ni-W)合金镀层,常被用于机械、电子及军工等领域。目前,将具有独特性质的纳米颗粒掺杂入金属基体所制备的纳米复合镀层材料日益受到重视。不同于直流电沉积,脉冲电沉积具有降低浓差极化、增加阴极活性极化的特点。因此利用多元材料复合的协同优势和脉冲电沉积的技术优势,能制备出具有优异的耐腐蚀性能、机械性能、电催化性能的纳米复合镀层。本论文采用脉冲电沉积的方法,成功制备了镍-钨/多壁碳纳米管(Ni-W/MWCNTs)、镍-钨/氮化硅(Ni-W/Si3N4)、镍-钨/氮化硼(Ni-W/BN(h))纳米复合镀层,系统地研究了镀层的制备工艺及性能。对于Ni-W/MWCNTs纳米复合镀层,探讨了电流密度、搅拌速度以及镀液中MWCNTs的加量等工艺条件对MWCNTs复合量的影响,得到最佳制备工艺:MWCNTs 加量 3 g/L、电流密度 5 A/dm2、搅拌速度 200 rpm。Ni-W/MWCNTs 纳米复合镀层的显微硬度随着镀层中纳米粒子含量的增加而升高,而磨损率随之降低。Ni-W/MWCNTs纳米复合镀层的摩擦系数明显低于Ni-W合金镀层。镀层的耐腐蚀性能利用开路电位测试、电化学阻抗谱测试、极化曲线测试和腐蚀浸泡实验进行分析。研究发现,Ni-W/MWCNTs纳米复合镀层在中性、酸性及碱性的3.5wt%NaCl溶液中的抗腐蚀性均明显优于Ni-W合金镀层。对于Ni-W/Si3N4纳米复合镀层,研究了脉冲频率、占空比以及镀液中Si3N4纳米颗粒加量等因素对表面形貌、结构以及Si3N4纳米颗粒含量的影响。结果表明,最佳工艺条件为:Si3N4纳米颗粒加量30 g/L、脉冲频率1000 Hz、占空比60%。Ni-W/Si3N4纳米复合镀层的显微硬度最高可达到Ni-W合金镀层的两倍。与Ni-W合金镀层相比,Ni-W/Si3N4纳米复合镀层的自腐蚀电流密度更小,自腐蚀电位更高,耐腐蚀性能更好,同时表现出良好的耐摩擦磨损性能,磨损率随着Si3N4纳米颗粒加量的增加而呈现先减小后增大的趋势。对于Ni-W/BN(h)纳米复合镀层,考察了脉冲频率、镀液温度、镀液中BN(h)纳米粒子加量对显微硬度、沉积速率以及表面形貌的影响。结果表明,最佳工艺条件为:BN(h)纳米粒子加量5 g/L、脉冲频率1000 Hz、镀液温度70℃。Ni-W/BN(h)纳米复合镀层的耐腐蚀性能高于Ni-W合金镀层,且随着镀液中BN(h)纳米粒子加量的增大而增大。Ni-W/BN(h)纳米复合镀层的磨损率和摩擦系数远远低于Ni-W合金镀层。提高复合镀层中BN(h)纳米粒子的含量,镀层的摩擦系数和磨损率随之降低。
[Abstract]:Nickel-tungsten (Ni-W) alloy coatings with excellent properties and simple process are often used in mechanical, electronic and military industries. At present, nano-composite coating materials prepared by doping nano-particles into metal substrates have been paid more and more attention. Unlike DC electrodeposition, pulse electrodeposition has the characteristics of decreasing concentration polarization and increasing cathodic active polarization. Therefore, nanocomposite coatings with excellent corrosion resistance, mechanical properties and electrocatalytic properties can be prepared by using the synergistic advantages of multicomponent materials and the technical advantages of pulse electrodeposition. In this paper, Ni-W / MWCNTs, Ni-W / Si _ 3N _ 4 and Ni-W / W / BN (h) nanocomposite coatings were successfully prepared by pulse electrodeposition. For Ni-W / MWCNTs nanocomposite coating, the effects of current density, stirring speed and the amount of MWCNTs in bath on the composite amount of MWCNTs were discussed. The results show that the microhardness of the nano-composite coating increases with the increase of the content of nano-particles in the coating, the optimum preparation technology is 3 g / L, the current density is 5A / dm2and the stirring speed is 200rpm.Ni-W / MWCNTs nano-composite coating. The friction coefficient of Ni-W / MWCNTs nanocomposite coating is obviously lower than that of Ni-W alloy coating. The corrosion resistance of the coating was analyzed by open-circuit potential test, electrochemical impedance spectroscopy, polarization curve test and corrosion immersion test. It is found that the corrosion resistance of Ni-W / MWCNTs nanocomposite coating in neutral, acidic and alkaline 3.5 wtNaCl solution is obviously better than that of Ni-W alloy coating. For Ni-W / Si _ 3N _ 4 nanocomposite coating, the effects of pulse frequency, duty cycle and the amount of Si _ 3N _ 4 nanoparticles in the bath on the surface morphology, structure and content of Si _ 3N _ 4 nanoparticles were studied. The results show that the optimum conditions are as follows: 30 g / L, pulse frequency 1000 Hz, duty cycle ratio 60%. Ni-W / Si 3N 4 nanocomposite coating has the highest microhardness twice as high as Ni-W alloy coating. Compared with Ni-W alloy coating, Ni-W / Si _ 3N _ 4 nanocomposite coating has lower corrosion current density, higher corrosion potential, better corrosion resistance and better friction and wear resistance. The wear rate decreases first and then increases with the increase of the amount of Si _ 3N _ 4 nanoparticles. The effects of pulse frequency, bath temperature and amount of BN (h) nanoparticles on microhardness, deposition rate and surface morphology of Ni-W / BN (h) nanocomposite coatings were investigated. The results show that the optimum conditions are as follows: adding 5 g / L of (h) nanoparticles, pulse frequency 1000 Hz, bath temperature 70 鈩，
本文编号：2123168
[Abstract]:Nickel-tungsten (Ni-W) alloy coatings with excellent properties and simple process are often used in mechanical, electronic and military industries. At present, nano-composite coating materials prepared by doping nano-particles into metal substrates have been paid more and more attention. Unlike DC electrodeposition, pulse electrodeposition has the characteristics of decreasing concentration polarization and increasing cathodic active polarization. Therefore, nanocomposite coatings with excellent corrosion resistance, mechanical properties and electrocatalytic properties can be prepared by using the synergistic advantages of multicomponent materials and the technical advantages of pulse electrodeposition. In this paper, Ni-W / MWCNTs, Ni-W / Si _ 3N _ 4 and Ni-W / W / BN (h) nanocomposite coatings were successfully prepared by pulse electrodeposition. For Ni-W / MWCNTs nanocomposite coating, the effects of current density, stirring speed and the amount of MWCNTs in bath on the composite amount of MWCNTs were discussed. The results show that the microhardness of the nano-composite coating increases with the increase of the content of nano-particles in the coating, the optimum preparation technology is 3 g / L, the current density is 5A / dm2and the stirring speed is 200rpm.Ni-W / MWCNTs nano-composite coating. The friction coefficient of Ni-W / MWCNTs nanocomposite coating is obviously lower than that of Ni-W alloy coating. The corrosion resistance of the coating was analyzed by open-circuit potential test, electrochemical impedance spectroscopy, polarization curve test and corrosion immersion test. It is found that the corrosion resistance of Ni-W / MWCNTs nanocomposite coating in neutral, acidic and alkaline 3.5 wtNaCl solution is obviously better than that of Ni-W alloy coating. For Ni-W / Si _ 3N _ 4 nanocomposite coating, the effects of pulse frequency, duty cycle and the amount of Si _ 3N _ 4 nanoparticles in the bath on the surface morphology, structure and content of Si _ 3N _ 4 nanoparticles were studied. The results show that the optimum conditions are as follows: 30 g / L, pulse frequency 1000 Hz, duty cycle ratio 60%. Ni-W / Si 3N 4 nanocomposite coating has the highest microhardness twice as high as Ni-W alloy coating. Compared with Ni-W alloy coating, Ni-W / Si _ 3N _ 4 nanocomposite coating has lower corrosion current density, higher corrosion potential, better corrosion resistance and better friction and wear resistance. The wear rate decreases first and then increases with the increase of the amount of Si _ 3N _ 4 nanoparticles. The effects of pulse frequency, bath temperature and amount of BN (h) nanoparticles on microhardness, deposition rate and surface morphology of Ni-W / BN (h) nanocomposite coatings were investigated. The results show that the optimum conditions are as follows: adding 5 g / L of (h) nanoparticles, pulse frequency 1000 Hz, bath temperature 70 鈩，
本文编号：2123168
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