电刷镀Ni-Mo合金摩擦学研究与耐磨性结构分析

发布时间：2018-06-13 01:31

本文选题：电刷镀 + Ni-Mo合金　；参考：《聊城大学》2015年硕士论文

【摘要】：槽镀Ni-Mo合金镀层不仅具有较高的机械强度还具有优良的耐磨性、耐蚀性和耐热性,良好的Ni-Mo合金镀层可以用以取代硬铬镀层从而减小对环境的污染。本文研制出了Ni-Mo合金刷镀液并采用电刷镀工艺方法在45#钢基体表面成功制备出Ni-Mo合金刷镀层,研究了镀液组成和工艺参数对电刷镀Ni-Mo合金镀层表面形貌、显微硬度及耐磨性的影响并分析了其原因;借助X射线衍射(XRD)、扫描电镜(SEM)等材料分析方法,对不同工艺条件和镀液配方下获得的Ni-Mo合金刷镀层的组织与结构进行分析研究,探究了Ni-Mo合金镀层物理化学性能变化的规律。试验结果和理论分析表明:1、Ni-Mo合金刷镀层呈晶态,在结构上是一个以Ni为溶剂,以Mo为溶质的置换型固溶体,该镀层与基体的结合强度较高且具有较高的显微硬度和耐磨性,还具有一定的耐蚀性。2、在电刷镀Ni-Mo合金工艺参数中,刷镀工作电压及电极相对运动速度对电刷镀镀层沉积速度、显微硬度、表面形貌及耐磨性都有较明显的影响,其中工作电压对刷镀镀层性能影响最大。3、改变Ni-Mo合金刷镀工艺参数可以细化镀层结构,优化Ni-Mo合金镀层表面形貌,提高镀层的硬度及耐磨性。在工作电压14V,电极相对运动速度11.3m/min时,刷镀Ni-Mo合金镀层的显微硬度达到最大,所得镀层晶粒细小,表面形貌均匀致密,且具有较高的耐磨性。4、随着刷镀液中硫酸镍浓度的提高,Ni-Mo合金镀层晶粒沿原子排列较密集的(111)晶面生长;刷镀液中钼酸钠浓度的增加,有利于Ni-Mo合金镀层晶粒沿原子排列较稀疏的(220)晶面生长。5、Ni-Mo合金刷镀液中硫酸镍和钼酸钠浓度的增加,都能明显提高镀层的显微硬度及耐磨性,但其强化机理不同:硫酸镍浓度增加使晶粒细化;钼酸钠浓度增加使镀层畸变位错增多。6、全面分析了Ni-Mo合金镀液组成对镀层表面形貌和镀层性能的影响,优选出电刷镀Ni-Mo合金较为理想的镀液配方。当硫酸镍浓度控制在400~500g/L,钼酸钠浓度控制在25~30g/L时,Ni-Mo合金刷镀层不仅具有良好的表面形貌且具有较高显微硬度和耐磨性。
[Abstract]:The Ni-Mo alloy coating not only has high mechanical strength, but also has excellent wear resistance, corrosion resistance and heat resistance. A good Ni-Mo alloy coating can be used to replace the hard chromium coating and reduce the pollution to the environment. In this paper, Ni-Mo alloy brush plating bath was developed and Ni-Mo alloy brush coating was successfully prepared on the surface of 4steel substrate by the method of brush plating. The surface morphology of Ni-Mo alloy coating by bath composition and process parameters was studied. The effects of microhardness and wear resistance on the microstructure and structure of Ni-Mo alloy brush coatings obtained under different technological conditions and bath formulations were studied by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The change of physical and chemical properties of Ni-Mo alloy coating was studied. The experimental results and theoretical analysis show that the Ni-Mo alloy brush coating is crystalline and is a replacement solid solution with Ni as solvent and Mo as solute in structure. The bonding strength between the coating and the substrate is high, and the coating has high microhardness and wear resistance. In the process parameters of brush plating Ni-Mo alloy, the working voltage of brush plating and the relative moving speed of electrode have obvious effects on deposition speed, microhardness, surface morphology and wear resistance of brush plating coating. The working voltage has the greatest influence on the performance of brush plating coating. Changing the technological parameters of Ni-Mo alloy brush plating can refine the coating structure, optimize the surface morphology of Ni-Mo alloy coating, and improve the hardness and wear resistance of the coating. When the working voltage is 14V and the relative speed of electrode is 11.3m/min, the microhardness of Ni-Mo alloy coating obtained by brush plating reaches the maximum, the grain size of the coating is fine and the surface morphology is uniform and compact. With the increase of nickel sulfate concentration in brush plating solution, the grain size of Ni-Mo alloy deposit grows along the crystal plane with dense atomic arrangement, and the concentration of sodium molybdate in brush plating solution increases. It is advantageous to increase the concentration of nickel sulfate and sodium molybdate in Ni-Mo alloy plating solution by increasing the grain size of Ni-Mo alloy coating along the sparsely arranged crystal plane of Ni 220), which can obviously improve the microhardness and wear resistance of the coating. However, the strengthening mechanism is different: the increase of nickel sulfate concentration makes the grain refinement, and the increase of sodium molybdate concentration leads to the increase of dislocations of the coating. The effect of the composition of Ni-Mo alloy plating bath on the surface morphology and coating properties is analyzed. An ideal solution formula for brush plating of Ni-Mo alloy was selected. When the concentration of nickel sulfate is controlled at 400g / L and sodium molybdate concentration is controlled at 2530g / L, the Ni-Mo alloy brush coating not only has good surface morphology, but also has high microhardness and wear resistance.
【学位授予单位】：聊城大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ153.2

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