Fabrication and corrosion resistance of hybrid coatings on pure magnesium by combining plasma electrolytic boronizing with micro-arc oxidation

被引：0
作者：
Sun L. [1 ]
Ma Y. [1 ]
Li Q.-H. [1 ]
Wang S. [1 ]
Wang Z.-Y. [1 ]
机构：
[1] State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou
来源：
Surface Technology | 2021年 / 50卷 / 06期
关键词：
Corrosion resistance; Hybrid coating; Magnesium; Micro-arc oxidation; Plasma electrolytic boronizing; Surface modification;
D O I：
10.16490/j.cnki.issn.1001-3660.2021.06.006
中图分类号：
学科分类号：
摘要：
The aim of the research is to prepare a novel hybrid coating on the surface of pure magnesium to improve its corrosion resistance. Pure magnesium was pretreated by plasma electrolytic boronizing (PEB) in borax aqueous solution to obtain the surface modified layer, and then it was processed by micro-arc oxidation (MAO) in silicate-based aqueous solution to fabricate the PEB+MAO novel hybrid coating. The microstructure, element distribution and phase composition of the coatings were analyzed by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD), respectively. The anti-corrosion resistance of the coatings was characterized by potentiodynamic polarization curve and electrochemical impedance spectroscope (EIS). The results show that the PEB process of pure magnesium involves four stages, namely ionization, replacement, adsorption and diffusion. The obtained PEB surface modified layer consists of the oxide layer and the diffusion layer. During the growth of the PEB+MAO hybrid coating, instead of simple stacking of layers, overlapping is observed in its thickness direction. In the process of plasma electrolytic saturation, B element infiltrates and forms a layer that reduces the surface chemical activity of pure magnesium substrate but improves its microstructure, thus bringing the corrosion current density of the PEB+MAO hybrid coating down by 3, 2 and 1 orders of magnitude compared with the substrate, single PEB modified layer and single MAO coating, respectively. Meanwhile, according to EIS analysis, the PEB+MAO hybrid coating can provide relatively longer corrosion protection. In addition, the mechanism of formation of PEB surface modified layer and the PEB+MAO hybrid coating is also analyzed, and the physical models are built. In summary, PEB pretreatment has a dramatic effect on the thickness, compactness and chemical composition of the PEB+MAO hybrid coating, thus significantly enhancing the corrosion resistance of pure magnesium. This method for fabrication of the novel hybrid coating is expected to be further applied to magnesium alloys to improve its anti-corrosion ability and bearing capacity. © 2021, Chongqing Wujiu Periodicals Press. All rights reserved.
引用
收藏
页码：64 / 76
页数：12
相关论文
共 54 条
  • [41] Aliofkhazraei M., Taheri P., Sabour Rouhaghdam A., Et al., Study of nanocrystalline plasma electrolytic carbonitriding for CP-Ti[J], Materials science, 43, 6, pp. 791-799, (2007)
  • [42] Sun L., Ma Y., Wang J.-S., Et al., Preparation and corrosion resistance of hybrid coatings formed by PEN/C plus PEO on AZ91D magnesium alloys[J], Surface and coatings technology, 390, pp. 1-13, (2020)
  • [43] Sheng Y.-Y., Zhang Z.-G., Li W., Effects of pulse frequency and duty cycle on the plasma discharge characteristics and surface microstructure of carbon steel by plasma electrolytic nitrocarburizing[J], Surface and coatings technology, 330, pp. 113-120, (2017)
  • [44] Abuali Galedari S., Mousavi Khoei S.M., Effect of pulse frequency on microstructure and surface properties of Ck45 steel treated by plasma electrolysis method[ J], Journal of alloys and compounds, 551, pp. 415-421, (2013)
  • [45] Wu J., Liu R., Xue W.-B., Et al., Analyses of quenching process during turn-off of plasma electrolytic carburizing on carbon steel[J], Applied surface science, 316, pp. 102-107, (2014)
  • [46] Afsar Kazerooni N., Bahrololoom M.E., Shariat M.H., Et al., Effect of ringer’s solution on wear and friction of stainless steel 316L after plasma electrolytic nitrocarburising at low voltages[J], Journal materials science technology, 27, 10, pp. 906-912, (2011)
  • [47] Tsotsos C., Yerokhin A.L., Wilson A.D., Et al., Tribological evaluation of AISI 304 stainless steel duplex treated by plasma electrolytic nitrocarburising and diamond-like carbon coating[J], Wear, 253, pp. 986-993, (2002)
  • [48] Han S.H., Chun J.S., A study on the electroboronizing of steel by superimposed cyclic current[J], Journal of materials science, 15, 6, pp. 1379-1386, (1980)
  • [49] Liu R., Wang B., Wu J., Et al., Spectroscopic investigation of plasma electrolytic borocarburizing on q235 low-carbon steel[J], Applied surface science, 321, pp. 348-352, (2014)
  • [50] Dong H.-R., Ma Y., Guo H.-X., Et al., Multidimensional investigation on coating growth of micro arc oxidation on AZ91D magnesium alloys[J], The Chinese journal of nonferrous metals, 25, 3, pp. 690-696, (2015)
123456