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摘要：本论文利用脉冲电沉积法制备了Ni-Mo-Sm(Ce)-MoSi2复合镀层，并分别研究了Sm(Ce)浓度、电流密度、脉冲频率、占空比及电镀时间对于Ni-Mo-Sm(Ce)-MoSi2复合镀层硬度的影响，分别用扫描电镜(SEM)、电子能谱仪(EDX)、X射线衍射仪(XRD)、热膨胀仪(DIL)及摩擦磨损试验机对复合镀层进行了表征。研究结果表明，在PEG6000浓度为0.09g/L、MoSi2浓度为8g/L、pH为8.3、转速为400r/min、温度为43℃时，制备Ni-Mo-Sm-MoSi2复合镀层的较佳工艺条件为：Sm3+浓度0.4g/L、电流密度19.5A/dm2、脉冲频率2500Hz、占空比1/2、电镀时间35min；制备Ni-Mo-Ce-MoSi2复合镀层的较佳工艺条件为：Ce3+浓度0.2g/L、电流密度19.5A/dm2、脉冲频率2500Hz、占空比3/4、电镀时间25min。在这两个较优条件下测得的复合镀层硬度分别为736.54HV和826.92HV，与Ni-Mo-MoSi2镀层(652.9HV)相比较，硬度分别提高了12.81%和26.65%。通过表征可知，复合镀层皆为晶态结构，其中Ni-Mo-Sm-MoSi2复合镀层表面结节较大且稀，而Ni-Mo-Ce-MoSi2复合镀层表面结节更细密。与Ni-Mo-MoSi2复合镀层0.35mg的磨损量相比，Ni-Mo-Sm-MoSi2复合镀层(0.21mg)的磨损量降低了40%，Ni-Mo-Ce-MoSi2复合镀层(0.30mg)的磨损量则降低了14.29%。5349
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创新点：本课题来源于国家自然科学基金项目，目前有关于运用脉冲电沉积法制备Ni-Mo-Sm(Ce)-MoSi2复合镀层的文献还未见报道。
关键词： 稀土元素；二硅化钼；复合镀；电镀
Study on Pulse Electrodepostion and Property of Ni-Mo-Sm(Ce)-MoSi2 Composite Coating
Abstract:Preparation of Ni-Mo-Sm(Ce)-MoSi2 composite coating by using pulse plating method.The effects of concentration of Sm(Ce),current density,frequency,duty-cycle,plating time on the property of composite coatings were studied.We analyze the composite coatings by scanning electron microscopy(SEM), energy disperse X-ray detectors (EDX),X-ray diffraction(XRD),thermal expansion instrument(DIL) and friction and wear tester.The results show that when PEG6000 is 0.09g/L,concentration of MoSi2 is 8g/L,stir speed is 400r/min,temperature is 43℃,the optimal operating conditions to prepare Ni-Mo-Sm-MoSi2 composite coating as follow:concentration of Sm3+ is 0.4g/L, current density is 19.5A/dm2, frequency is 2500Hz,duty-cycle is 1/2,plating time is 35min,and the maximum hardness is 736.54HV; the optimal operating conditions to prepare Ni-Mo-Ce-MoSi2 composite coating as follow:concentration of Ce3+ is 0.2g/L,current density is 19.5A/dm2, frequency is 2500Hz,duty-cycle is 3/4,plating time is 25min, and the maximum hardness is 826.92HV. Compared the hardness with the Ni-Mo-MoSi2(652.9HV),the Ni-Mo-Sm-MoSi2 increased 12.81%,and Ni-Mo-Ce-MoSi2 increased 26.65%.To characterize the Ni-Mo-Sm(Ce)-MoSi2,we can find that all of coatings are crystalline,the particles on Ni-Mo-Sm-MoSi2 composite coatings are small protuberance group shape,and on the surface of the Ni-Mo-Ce-MoSi2 composite coatings are finer.Compared the wear resistance with the Ni-Mo-MoSi2(0.35mg), the Ni-Mo-Sm-MoSi2 (0.21mg)reduced 40%, and the Ni-Mo-Ce-MoSi2 (0.30mg) reduced 14.29%.
Creative ideas in this paper:
The topic comes from the National Natural Science Foundation of China.The current literatures about the preparation of Ni-Mo-Sm(Ce)-MoSi2 composite coating by pulse electrodeposition have not been reported yet.
KeyWords: rare earth elements;MoSi2;composite coating;electroplating
目录
1 前言 5
1.1 选课意义 5
1.2 文献综述 5
1.2.1 二硅化钼 ..5
1.2.2 脉冲复合镀的概念 .5
1.2.3 复合镀的机理及特点 6
1.2.4 复合镀的种类 7