Investigation of Microstructure, Hardness, and Corrosion Resistance of Ni-P-GO Electroless Nanocomposite Coating on AZ31D Alloy Surface

Document Type : Original Research Article


Department of Metallurgy and Materials Engineering, Karaj Branch, Islamic Azad University, Karaj, Alborz, Iran


In the present study, the Ni-P-GO nanocomposite coating was applied to the surface of AZ31D alloy through electroless plating process. To achieve the nanocomposite coating, 5 g/L Graphene Oxide (GO) was added to the plating bath. By changing the pH of the bath, coatings were created in three ranges of low, medium, and high phosphorus on the surface of AZ31D. According to the results, by increasing the phosphorus content, the amount of graphene oxide absorbed in the coating increased. Microstructural examination by Scanning Electron Microscopy (SEM) showed that all coatings formed on the substrate had the cauliflower morphology. Phase analsis of the coating by X-Ray Diffraction (XRD) showed that at a low phosphorus level, the coating is semi-amorphous; however, with increasing phosphorus content, the coating becomes completely crystalline. The highest hardness value of the specimen was observed with the lowest amount of phosphorus. The microhardness measurments showed that the hardness decreased with increasing the amount of phosphorus so that the minimum hardness of the specimen containing 14.97 wt.% phosphorus was measured at 521 Hv50. Contrary to the morphology, phosphorus levels have a significant effect on the structure and hardness of Ni-P-GO nanocomposite coatings. As the amount of phosphorus increased, the corrosion resistance of the coating increased. This is attributed to the reduction of the current of corrosion and more positive potential values.


Main Subjects


    1. Gu, C., Jiang, Z., “Multilayer Ni-P Coating for Improving the Corrosion Resistance of AZ91D Magnesium Alloy”, Advanced Engineering Materials, Vol. 7, No. 11, (2005), 1032-1036.
    2. Kanta, A. F., Vitry, V., Delaunois, F., “Wear and corrosion resistance behaviours of autocatalytic electroless plating”, Journal of Alloys and Compounds, Vol. 486, No. 1-2, (2009), L21-L23 .
    3. Hu, R., Su, Y., Liu, Y., Liu, H., Chen, Y., Cao, C., Ni, H., “Deposition Process and Properties of Electroless Ni-P-Al2O3 Composite Coatings on Magnesium Alloy”, Nanoscale Research Letters, Vol. 13, No. 1, (2018), 1-8.
    4. Ashtiani, A. A., Faraji, S., Iranagh, S. A., Faraji, A. H., “The study of electroless Ni–P alloys with different complexing agents on Ck45 steel substrate”, Arabian Journal of Chemistry, Vol. 10, (2017), S1541-S1545.
    5. Thirumalaikumarasamy, D., Shanmugam, K., Balasubramanian,  V., “Corrosion performance of atmospheric plasma sprayed alumina coatings on AZ31B magnesium alloy under immersion environment”, Journal of Asian Ceramic, Vol. 2, No. 4, (2014), 403-415.
    6. Rao, K. P., Sankar, A., Rafi, H. K., Ram, G. J., Reddy, G. M., “Friction surfacing on nonferrous substrates: a feasibility study”, The International Journal of Advanced Manufacturing Technology, Vol. 65, No. 5-8, (2013), 755-762.
    7. Liu, Q., Ma, Q. X., Chen, G. Q., Cao, X., Zhang, S., Pan, J. L., Zhang, G., Shi, Q. Y., “Enhanced corrosion resistance of AZ91 magnesium alloy through refinement and homogenization of surface microstructure by friction stir processing”, Corrosion Science, Vol. 138, (2018),  284-296.
    8. Han, H. M., Wang, D. T., Yu, H. Q., Zuo, M., Wang, L. H., Zhao, D. G., “Ceria Coatings Prepared by Sol-Gel Approach on AZ91 Magnesium Alloy”, In Materials Science Forum, Vol. 898, (2017), 1369-1380, Trans Tech Publications Ltd.
    9. Zhang, J., Song, Z., Yu, G., Hu, B., Zhang, X., “Corrosion Behavior of Electroless Ni-P/Ni-B Coating on Magnesium Alloy AZ91D in NaCl Environment”, International Journal of Electrochemcal Science, Vol. 11, (2016), 10053-10066.
    10. Huang, C. A., Yeh, Y. H., Lin, C. K, Hsieh, C. Y., “Copper Electrodeposition on a Magnesium Alloy (AZ80) with a U-Shaped Surface”, Materials, Vol. 7, No. 11, (2014), 7366-7378.
    11. Shajari, Y., Alizadeh, A., Seyedraoufi, Z. S., Razavi, S. H., Shamakhi, H., “The effect of heat treatment on wear characteristics of nanostructure Ni-B coating on marine bronze”, Materials Research Express, Vol. 6, No. 10, (2019), 105040.
    12. Serin, I. G., Göksenli, A., Yüksel, B., Yildiz, R. A., “Effect of Annealing Temperature on the Corrosion Resistance of Electroless Ni-B-Mo Coatings”, Journal of Materials Engineering and Performance, Vol. 24, No. 8, (2015), 3032-3037.
    13. Shajari, Y., Porhonar, M., Seyedraoufi, Z. S., Razavi, S. H., Baghdadabad, D. M., Yousefnia, H., Farahani, M., “Improvement of the NiBrAl casting alloy surface properties by electroless Ni-B plating for dynamic marine application”, Physical Mesomechanics, Vol. 23, No. 1, (2020), 81-88.
    14. Jiang, J., Chen, H., Zhu, L., Qian, W., Han, S., Lin, H., Wu, H., “Effect of heat treatment on structures and mechanical properties of electroless Ni–P–GO composite coatings”, RCS Advances, Vol. 6, No. 110, (2016), 109001–109008.
    15. Wu, H., Liu, F., Gong, W., Ye, F., Hao, L., Jiang, J., Han, S., “Preparation of Ni–P–GO composite coatings and its mechanical properties”, Surface and Coating Technology, Vol. 272, (2015), 25-32.
    16. Oraon, B., Majumdar, G., Ghosh, B., “Improving hardness of electroless Ni-B coating using optimized deposition conditions and annealing”, Materials & Design, Vol. 29, No. 7, (2008), 1412-1417.
    17. Loto, C. A., “Electroless Nickel Plating : A Review”, Silicon, Vol. 8, No.2, (2016), 177-186.
    18. Zhang, W. X., Jiang, Z. H., Li, G. Y., Jiang, Q., Lian, J. S., “Electroless Ni-P/Ni-B duplex coatings for improving the hardness and the corrosion resistance of AZ91D magnesium alloy”, Applied Surface Science, Vol. 254, No. 16, (2008), 4949–4955.
    19. Portnoi, V. K., Leonov, A. V., Fedotov, S. A., “Solid-phase synthesis in Ni-Mg and Ni-Mg-C systems upon ball milling of powder mixtures”, Bulletin of the Russian Academy of Sciences: Physics, Vol. 73, No. 9, (2009), 1211.
    20. Baskaran, I., Kumar, R. S., Narayanan, T. S., Stephen, A., “Formation of electroless Ni–B coatings using low temperature bath and evaluation of their characteristic properties”, Surface and Coatings Technology, Vol. 200, (2006), No. 24, 6888–6894.
    21. Czagány, M., Baumli, P., “Effect of pH on the characterstic of electroless Ni-P coatings”, Journal of Mining and Metallurgy Section B Metallurgy, Vol. 53, No. 3,  (2017), 327-332.
    22. Riedel, W., Electroless Nickel Plating, Metals Park, Ohio: ASM International, (1991).
    23. Ashassi-Sorkhabi, H., Es'haghi, M., “Corrosion resistance enhancement of electroless Ni–P coating by incorporation of ultrasonically dispersed diamond nanoparticles”, Corrosion Science, Vol. 77, (2013), 185-193.
    24. Elsener, B., Crobu, M., Scorciapino, M. A., Rossi, A., “Electroless deposited Ni–P alloys: corrosion resistance mechanism”, Journal of Applied Electrochemistry, Vol. 38, No. 7, (2008), 1053-1060.
    25. Bozzoni, B., Lenardi, C., Serra, M., Faniglulio, A., “Electrochemical and X-ray photoelectron spectroscopy investigation into anodic behaviour of electroless Ni–9.5 wt%P in acidic chloride environment”, British Corrosion Journal, Vol. 37, No. 3, (2002), 173-181.
    26. Ghavidel, N., Allahkaram, S. R., Naderi, R., Barzegar, M., Bakhshandeh, H., “Corrosion and wear behavior of an electroless Ni-P/nano-SiC coating on AZ31 Mg alloy obtained through environmentally-friendly conversion coating”, Surface and Coating Technology, Vol. 382, (2020), 125156.