再制造零部件表面的电化学检测及NiP化学复合镀修复

发布时间：2018-05-18 03:10

本文选题：再制造 + 电化学检测　；参考：《天津大学》2012年硕士论文

【摘要】：再制造技术环保节约，是循环经济的重要组成，近些年来受到广泛的关注。工程机械再制造技术包括清洗技术、检测技术、加工修复技术这三个主要方面。我国的检测技术和加工修复技术都处于研究的初级阶段，亟需进一步研究。本文首先通过电化学实验来确定材料表面缺陷对电化学测试结果的影响，提出了一种新的表面缺陷检测方法，并通过实际应用来验证其可靠性。然后通过化学镀实验来确定不同纳米颗粒浓度对镍-磷-纳米颗粒复合镀层性能的影响，为用镍-磷-纳米颗粒复合镀修复再制造零部件提供理论依据。主要研究成果如下：采用电化学阻抗谱测试、电化学噪声测试和电镜观察，并结合EIS和EN的测试原理，，对材料表面缺陷对测试结果的影响及其原因进行分析。结果表明：相比于无缺陷的试样，有缺陷试样的容抗弧半径小，阻抗模值低，时域谱波动剧烈，噪声频域谱PSD斜率k更接近-20dB dec-1，是发生局部腐蚀的特征。三种测试结果吻合性很好，证实表面缺陷的电化学表征是可行的；采用电化学方法对机械工程中的再制造零部件进行缺陷检测，并用三维显微镜观察和超声相控阵实验对检测效果进行评价，验证用电化学方法检测表面缺陷的实际可操作性。结果表明：电化学方法检测表面缺陷有较好的准确性，可用于实际应用。采用镍-磷-纳米颗粒化学复合镀技术，研究了不同浓度的碳纳米管（0g/L，0.5g/L，1.0g/L，1.5g/L）和纳米二氧化钛（0g/L，1g/L，2g/L，3g/L）分别对复合镀层的耐蚀性能、耐磨损性能、表面硬度等的影响。结果表明：相对于Ni-P镀层，复合镀层耐蚀性更优，但是随着碳纳米管浓度的增加而降低，在0.5g/L时耐蚀性能最好。耐蚀性随着纳米二氧化钛浓度的增加而增加；相对于Ni-P镀层，Ni-P-碳纳米管镀层耐磨损性能和表面硬度值也更优，而且随着碳纳米管浓度的增加而提高。Ni-P-纳米二氧化钛镀层耐磨损性能和表面硬度值却变差，但着纳米二氧化钛浓度的增加而提高。
[Abstract]:Environmental conservation of remanufacturing technology is an important component of circular economy, which has received extensive attention in recent years. The remanufacturing technology of construction machinery includes three main aspects: cleaning technology, testing technology and machining and repairing technology. The detection technology and the machining repair technology in our country are in the primary stage of research, and need to be further studied. In this paper, the influence of surface defects on the results of electrochemical measurement is determined by electrochemical experiments, and a new method of surface defect detection is proposed, which should be used to verify the reliability of the method. Then the influence of different concentration of nanoparticles on the properties of Ni-P nanoparticles composite coating was determined by electroless plating experiments, which provided a theoretical basis for repairing the remanufactured parts by Ni-P nanoparticles composite plating. The main findings are as follows: Electrochemical impedance spectroscopy (EIS), electrochemical noise measurement and electron microscopy were used to analyze the influence of surface defects on the test results and their causes. The results show that the defect samples have smaller capacitance arc radius, lower impedance mode value, sharp fluctuation of time-domain spectrum, and the noise frequency domain PSD slope k is closer to -20dB dec-1, which is the characteristic of local corrosion. The results of the three tests are in good agreement with each other, which proves that the electrochemical characterization of surface defects is feasible. The defect detection of remanufactured parts in mechanical engineering was carried out by electrochemical method. The detection effect was evaluated by three-dimensional microscope observation and ultrasonic phased array experiment. The practicability of using electrochemical method to detect surface defects was verified. The results show that the electrochemical method has good accuracy and can be used in practical application. The effects of different concentrations of carbon nanotubes (0 g / L 0. 5 g / L 1. 0 g / L 0 g / L 1 g / L 2 g / L 3 g / L) on the corrosion resistance, wear resistance and surface hardness of the composite coatings were studied by electroless composite plating technique. The results show that the corrosion resistance of the composite coating is better than that of the Ni-P coating, but the corrosion resistance of the composite coating decreases with the increase of the concentration of carbon nanotubes, and the corrosion resistance of the composite coating is the best in the case of 0.5g/L. The corrosion resistance of Ni-P- carbon nanotube coating increased with the increase of TIO _ 2 concentration, and the wear resistance and surface hardness of Ni-P- carbon nanotube coating were also better than that of Ni-P coating. With the increase of carbon nanotube concentration, the wear resistance and surface hardness of Ni-P- nano-TiO _ 2 coating become worse, but the increase of nano-titanium dioxide concentration increases.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：O657.1;TH16

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