电沉积镍-碳钠米管复合镀层的工艺研究

利用电沉积方法制备了镍-碳纳米管复合镀层.分析了镀液中碳纳米管的悬浮量、镀液温度、pH值、阴极电流密度及搅拌速度对镀层中碳纳米管含量的影响.扫描电镜结果表明,碳纳米管能均匀地嵌镶于基体中,并且端头露出,覆盖于基体表面.     

含纳米金刚石粉镍钴基复合镀层的研究

通过对爆轰制备的纳米金刚石粉进行去除杂质,亲水处理,制备出分散稳定的含纳米金刚石粉的镀液。利用这个镀液制备出含纳米金刚石粉的Ni—Co复合电镀层,并研究了镀液中分散不同含量纳米金刚石粉对制备镀层的表面形貌,晶粒尺寸的影响,镀液中纳米金刚石粉含量从2g／L增加到6g／L,镀层的晶粒尺寸减小近一半。纳米金刚石粉对晶粒的细化程度和镀层中含有的纳米金刚石粉的含量有很大关系。镀层的显微硬度与镀液中分散的纳米金刚石粉的含量并不成线性关系,镀层的显微硬度最大可达601．53HV。团聚的纳米金刚石粉导致镀层晶粒的异常长大。     

Ni-P-金刚石化学复合镀层耐磨性能研究

在镍磷化学镀的基础上,研究了微米、纳米金刚石化学复合镀工艺。采用正交试验方法,研究化学镀液、金刚石种类与浓度、表面活性剂种类与含量以及热处理温度对镀层耐磨性能的影响。通过超声搅拌,实验成功制备出具有优异耐磨性能的Ni-P-金刚石复合镀层。结果表明：对镀层耐磨性影响明显的因素依次为表面活性剂的种类和含量,金刚石颗粒的含量和种类,而镀液的种类和热处理温度对镀层耐磨性的影响较小。并且,最佳工艺为：添加阴离子表面活性剂,含量为1：15,复合颗粒为金刚石微粉,浓度为10g/L,镀层热处理温度为400℃。     

可溶性阳极电刷镀镍镀层的纳米晶结构及其热稳定性

采用可溶性阳极电刷镀制备镍镀层，XRD分析和TEM观察结果表明镀层为纳米晶结构，晶粒尺寸约20nm，具有（111）择优取向。镀镍层硬度随电刷镀电压和镀液温度的提高而增加，在一定值时达到最大值，然后随电压和镀液温度的继续提高而降低。而阴-阳极相对运动速度影响较小。低温退火时镀层的硬度随加热温度的提高而升高，300℃时达到最大值，然后随温度的升高而降低。可溶性阳极电刷镀纳米晶镍的热稳定性明显高于晶粒尺寸相近的槽镀纳米晶镍，对其原因进行初步探讨。     

镍-金刚石复合刷镀的工艺

河南信阳空军第一航空学院研究了镍-金刚石复合电刷镀工艺中施镀电压、施镀温度和镀笔与工件之间相对速度对复合镀层中金刚石含量和耐磨性能的影响，得到了制备高耐磨性镀层的最佳工艺参数，     

WC/Co含量对Ni-WC/Co纳米复合镀层腐蚀性能的影响

采用脉冲电沉积制备出Ni-WC/Co纳米复合镀层,研究镀液中WC/Co含量对复合镀层晶体结构、晶粒尺寸和硬度的影响;室温下,通过测试复合镀层在3.5%(质量分数)NaCl溶液中的电化学行为,分析镀层的耐蚀性能。结果表明:随着镀液中WC/Co含量增加,复合镀层平均晶粒尺寸先减小后增大,硬度则是先增大后减小,复合镀层的耐蚀性能是先升高后降低。当WC/Co含量为30 g/L时,复合镀层的平均晶粒尺寸最小,硬度最高,腐蚀电位(E_(corr))较高,腐蚀电流密度(I_(corr))最低,耐蚀性能最佳。     

温度对柔性摩擦辅助电沉积镍镀层组织结构的影响

为提高镀层质量,采用新型的柔性摩擦辅助电沉积技术在不含任何添加剂的Watts镀液中制备了镍镀层。利用SEM、AFM、XRD、TEM以及硬度计等手段分别对镀层的形貌、生长取向、结构和硬度进行了表征,并与无柔性介质摩擦作用下的电沉积镍进行了比较。结果表明:在20~50℃的温度范围内,柔性摩擦辅助电沉积镍镀层组织结构得到改善。电沉积镍镀层均为面心立方结构,随着镀液温度的升高,柔性摩擦辅助电沉积镍镀层的择优取向由(220)晶面向(111)晶面转变,表面逐渐变得平整致密,硬度(HV)从4550 MPa增加到4750 MPa后趋于平稳。当温度为50℃时,柔性摩擦辅助电沉积镍镀层的平均晶粒尺寸为91.6 nm,远小于电沉积镍的平均晶粒尺寸153.7 nm。     

可溶性阳极电刷镀镍镀层的纳米晶结构及其热稳定性

采用可溶性阳极电刷镀制备镍镀层,XRD分析和TEM观察结果表明镀层为纳米晶结构,晶粒尺寸约20nm,具有(111)择优取向.镀镍层硬度随电刷镀电压和镀液温度的提高而增加,在一定值时达到最大值,然后随电压和镀液温度的继续提高而降低.而阴-阳极相对运动速度影响较小.低温退火时镀层的硬度随加热温度的提高而升高,300℃时达到最大值,然后随温度的升高而降低.可溶性阳极电刷镀纳米晶镍的热稳定性明显高于晶粒尺寸相近的槽镀纳米晶镍,对其原因进行初步探讨.     

电弧喷涂快速模具工作表面的电刷镀强化实验研究

电弧喷涂快速制模多采用低熔点金属Zn或者Zn_Al合金 ,硬度低、耐磨性能较差 ,难以胜任模具工作时的恶劣工况。本试验选用快速镍和致密快镍两种镀液对其进行表面强化 ,对在不同施镀电压以及不同镀液始镀温度条件下获得的强化镀层的耐磨性能进行了对比分析 ,探讨了镀层耐磨性能与刷镀电压以及镀液温度的关系 ,得到了耐磨性能最好时的工艺参数     

40CrNiMo表面电刷镀的研究

为了改善40CrNiMo的耐磨、耐蚀性,提高其表面硬度,选用La2O3含量不同的镍磷镀液对40CrNiMo进行电刷镀,并对镀层性能进行研究。结果表明:40CrNiMo基体上刷镀镍磷镀层后,其镀层硬度、耐磨性、耐腐蚀性等表面性能得到明显提高。同时,在镍磷镀液中添加适量稀土有助于提高耐磨性能、耐腐蚀性能和硬度。     

Influence of SiO2 nano-particles on microstructures and properties of Ni-W-P/CeO2-SiO2 composites prepared by pulse electrodeposition

Ni-W-P base composites containing CeO2 and SiO2 nano-particles were prepared on common carbon steel surface by pulse co-deposition of Ni, W, P, CeO2 and SiO2 nano-particles. The influence of SiO2 concentrations in bath on microstructures and properties of Ni-W-P/CeO2-SiO2 composites was studied, and the characteristics were assessed by chemical compositions, element distribution, surface morphologies, deposition rate and microhardness. The results indicate that when SiO2 concentration in bath is controlled at 20 g/L, the composites possess the fastest deposition rate, the highest microhardness, compact microstructures, smaller crystallite sizes and uniform distribution of W, P, Ce and Si within Ni-W-P matrix metal. Increasing SiO2 concentration in bath from 10 to 20 g/L leads to the refinement in grain size and the inhomogeneity of microstructures. While when SiO2 concentration is increased to 30 g/L, the crystallite sizes increase again and some bosses with nodulation shape appear on the surface of composites.     

NiCl2 含量对电沉积 Ni-纳米 TiN 复合镀层过程的影响

目的针对氨基磺酸镍体系镀镍液,优化活化剂NiCl2的用量,提高Ni-纳米TiN复合镀层的性能。方法采用超声-脉冲电沉积工艺制备Ni-纳米Ti N复合镀层,研究NiCl2含量对镀液的电导率及复合镀层的厚度、显微硬度、表面微观形貌等的影响。结果镀液的电导率及复合镀层的厚度、显微硬度均随NiCl2含量的增加呈现先增大、后减小的变化趋势。当NiCl2的用量为30 g/L时,镀液的导电性能最佳,电导率值为61.3 m S/cm,复合镀层的厚度及显微硬度均达到最大值,分别为84μm和760HV,并且复合镀层表面平整光滑,晶粒尺寸最小。结论 NiCl2含量对镀液及复合镀层的性能有很大影响,适量的NiCl2可以防止阳极钝化,提高镀液的导电能力及沉积速率,使复合镀层的厚度增加,显微硬度提高,晶粒细化,微观形貌获得改善,性能提高。适宜的NiCl2用量为30 g/L。     

Microstructure and Performances of Nanocrystalline Zinc-nickel Alloy Coatings

THE STUDY on zinc-nickel alloy coatings isdeveloped rapidly because of their higher corrosionresistance and better mechanical characteristics[1-8].The zinc-nickel coatings provide improved corrosionprotection for steels in relatively aggressiveenvironments.It has been found that the maximumprotective ability can be reached with the nickel contentbetween12%and15%[9].Recently,several newzinc-nickel alloy technologies have been developed[10-15]and further researches for better coating andchara…     

气体搅拌下Cr-SiC复合镀层的研究

通过对市售碳化硅粉进行适当的化学和表面吸附改性,研究了机械搅拌和气体搅拌下标准镀铬液和添加稀土添加剂复合镀铬液中的施镀情况.利用扫描电镜,显微硬度计等对复合镀层的微观组织结构和性能进行了分析.结果表明机械搅拌下镀铬层中的SiC含量少,而在气体搅拌下则得到SiC弥散分布的复合镀层,复合镀层硬度较纯铬镀层有明显的提高,晶粒明显细化.     

Fabrication of conventional and nanostructured NiCrC coatings via HVAF technique

The conventional and nanostructured NiCrC （with chemical composition of 80%NiCr-20%CrC） coatings with high quality were fabricated via high velocity air-fuel（HVAF） spraying technique. The microstructures of these coatings were characterized by means of metallographic microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffractometry. A Vickers microhardness tester was used to determine the mechanical properties of the as-sprayed coatings. The single-line approximation（SLA） method was employed to calculate the grain size and microstrain of as-sprayed nanostructured coating based on the XRD data. The results show that nanostructured NiCrC coating possesses a more uniform and denser microstructure, much higher microhardness and better fracture toughness than its conventional counterpart. Both TEM observation and calculation results based on XRD profile show that as-sprayed nanostructured NiCrC coating has a homogeneous nanocrystalline microstructure with an average grain size of 40 nm.     

Effect of Microstructure on the Solid Particle Erosion Properties of Ni Plating

The effect of microstructure on erosion resistance of nickel plating was investigated in this study. Two electrode nickel plating processes, one with conventional nickel sulfamate electrolyte and the other with carbon nanotubes (CNTs) dispersed in the electrolyte, at various pulse frequencies were used to generate surface depositions of different microstructures. The samples were subjected to microstructural evaluations and mechanical property testing for microhardness and elastic modulus. Subsequently, erosion tests were conducted to evaluate the material’s erosion resistance under various plating conditions. It was found that both changes in pulse frequency and the addition of CNTs resulted in grain size refinement and surface morphology modification. Microhardness of the plating was observed to increase with the pulse frequency in the absence of CNTs. Erosion resistance increased with grain refinement initially due to the surface hardness increase but this effect subsided as the thickness of the deposition approached that of the plastic deformation layer caused by the erodent.     

激光熔覆Ni-Si金属硅化物复合材料涂层显微组织与耐蚀性

以Ni,Si,Cr元素粉末为原料 ,利用激光熔覆技术在A3钢表面制得了Ni Si金属硅化物复合材料涂层。分析了该涂层的显微组织 ,采用测定阳极极化曲线的方法评价了该涂层在 0 .5mol/LH2 SO4 及 3 .5 %NaCl水溶液中的耐蚀性能。结果表明 :激光熔覆Ni Si金属硅化物复合材料涂层组织由Ni2 Si初生胞状树枝晶及枝晶间少量FeNi/Ni31Si12 共晶组成 ,涂层表面平整、组织细小、与基体间为完全冶金结合 ;涂层组织显微硬度在HV80 0～ 95 0之间且沿层深分布均匀 ;由于涂层组织组成相Ni2 Si和Ni31Si12 等本身均具有很好的耐蚀性并具有快速凝固细小均匀的显微组织 ,激光熔覆Ni Si金属硅化物复合材料涂层在 0 .5mol/LH2 SO4 及 3.5 %NaCl水溶液中均表现出优良的耐蚀性能。激光熔覆Ni Si金属硅化物复合材料涂层可望成为一种很有发展前景的耐蚀涂层新材料。     

Cu含量对Ni基定向合金涂层组织与摩擦学性能的影响

采用火焰喷涂+感应重熔+强制冷却复合技术制备了Cu添加的Ni60/Cu定向结构复合涂层。系统研究了Cu含量对Ni60/Cu定向结构涂层微观组织、物相演变、微观硬度及摩擦磨损性能的影响。结果表明：在定向结构涂层形成过程中,Cu元素持续向晶粒内部扩散,导致涂层随着Cu含量增加,涂层硬度持续降低。Cu含量对涂层显微组织产生重要影响,当Cu含量为15%时,涂层定向结构组织呈垂直于界面生长特征,微观结构细密规整。当Cu含量为15%时,涂层以磨粒磨损为主,显示出最低的摩擦系数和最小的磨损率,充分发挥了Cu元素的减摩效果,但过量的Cu元素添加反而使涂层耐磨性能变差。     

硫脲对喷射电铸纳米晶铜组织与性能的影响

采用喷射电铸法制备了不同硫脲浓度下的纳米晶铜铸层,用SEM、XRD方法分析了硫脲对纳米晶铜铸层微观结构和晶粒大小的影响,并对纳米晶铜铸层的力学性能进行了测试.结果表明,硫脲能细化晶粒,致密铸层组织,显著提高铸层的抗拉强度和显微硬度;电铸液中硫脲浓度为10 mg/L时,可获得晶粒尺寸为29 nm的致密铜铸层,其显微硬度和抗拉强度分别为3.1 GPa和645 MPa.电铸液中硫脲浓度从5 mg/L增至10 mg/L时,纳米晶铜铸层的择优取向由(220)晶面转变为(111)晶面.     

Electrodeposition behavior and characteristics of Ni-carbon nanotube composite coatings

Ni-CNT (carbon nanotube) composite coatings were processed by electrodeposition and their hardness and corrosion characteristics were investigated with variations of CNT concentration in an electrolyte solution and electrodeposition current density. With increasing the CNT concentration in the electrodeposition bath and the current density, more CNTs are incorporated into Ni matrix. Hardness values of the Ni-CNT coatings are irrelevant to the CNT concentration in the solution, the current density, and current mode, implying poor adhesion of CNTs to Ni matrix. With increasing the CNT content in the coating, the corrosion resistance of the Ni-CNT composite coating becomes inferior due to the porous microstructure.