Russian Journal of Non-Ferrous Metals

, Volume 60, Issue 2, pp 200–206 | Cite as

Phase Composition and Wear Resistance of Coatings Formed on the VT6 Titanium Alloy by Plasma Electrolytic Oxidation

  • A. G. RakochEmail author
  • Phan Van TruongEmail author
  • A. A. GladkovaEmail author
  • N. A. PredeinEmail author


The growth kinetics of the coating during the plasma electrolytic oxidation (PEO) of the VT6 (Ti–6Al–4V) alloy with a specified density of 10 A/dm2 in an alkaline aqueous solution containing sodium aluminate (NaAlO2) in an amount of 40 g/L is investigated. The wear resistance of coatings of different thicknesses (30 and 80 μm) formed on the VT6 alloy is studied by the “pin-on-disc” test using a “High-temperature tribometer” automated friction machine and WYKO NT1100B optical profilometer. The dependences of the phase composition of coatings on the PEO duration and wear resistance of coatings on this composition are established. The following growth mechanisms of the coating thickness, which explain the growth kinetic features, are proposed: (i) the migration and diffusion of metal cations to the external phase interface in segments adjoining the microdischarges; (ii) the thermochemical transformation of deposited ions or polyanions, in particular, sodium tetrahydroxoaluminate; and (iii) high-temperature oxidation of the metallic base of the bottom of through coating pores, in which the plasma anodic microdischarges were implemented. The considered equivalent circuit of proceeding the anodic component of the alternate current during the PEO of the titanium alloy allows one to understand the causes of a substantial initial decrease in the coating growth rate during the PEO of the VT6 alloy without lowering the anodic voltage. The feature of this circuit is the presence of rheostats, because the flowing resistance of alternate current components depends largely on the PEO duration. It is shown that the presence of the high-temperature modification (α‑Al2O3) in the coating based on spinel TiAl2O5 makes it possible to increase the wear resistance of the VT6 alloy almost sixfold if the coating thickness is ~80 μm.


VT6 titanium alloy plasma electrolytic oxidation wear resistance coating growth mechanism high-temperature alumina modification 



  1. 1.
    Kolachev, B.A., Eliseev, Yu.S., Bratukhin, A.G., and Talalaev, V.D., Titanovye splavy v konstruktsiyakh i proisvodstve i aviatsionno-kostruktorskoi tekhnike (Titanium Alloys in Constructions and Production in the Aviation-Construction Technology), Moscow, MAI, 2001.Google Scholar
  2. 2.
    Kolachev, B.A., Livanov, V.A., and Bukhanova, A.A., Mekhanicheskie svoistva titana i ego splavov (Mechanical Properties of Titanium and Its Alloys), Moscow: Metallurgiya, 1974.Google Scholar
  3. 3.
    Babichev, A.P., Babushkina, N.A., Bratkovskii, A.M., et al., Fizicheskie velichiny: Spravochnik (Physical Quantities: Reference Book), Grigor’ev, I.S. and Meilikhov, E.Z., Eds., Moscow: Energozatrat, 1991.Google Scholar
  4. 4.
    Glazunov, S.G., Vazhenin, S.F., Zyukov-Batyrev, G.D., and Ratner, Ya.L., Primenenie titana v narodnom khozyaistve (Application of Titanium in National Economy), Kiev: Tekhnika, 1975.Google Scholar
  5. 5.
    Glazunov, S.G. and Moiseev, V.N., Konstruktsionnye titanovye splavy (Structural Titanium Alloys), Moscow: Metallurgiya, 1974.Google Scholar
  6. 6.
    Gordienko, P.S. and Gnedenkov, S.V., Mikrodugovoe oksidirovanie titana i ego splavov (Microarc Oxidation of Titanium and Its Alloys), Vladivostok: Dal’nauka, 1997.Google Scholar
  7. 7.
    Yerokhin, A.L., Leyland, A., and Matthews, A., Kinetic aspects of aluminiumtitanate layer formation on titanium alloys by plasma electrolytic oxidation, Appl. Surf. Sci., 2002, vol. 200, pp. 172–184.CrossRefGoogle Scholar
  8. 8.
    Zhukov, S.V. Suminov, I.V., Epel’fel’d, A.V., Zheltukhin, R.V., and Kantaeva, O.A., Physicomechanical properties, Structure, and phase composition of MAO coatings on titanium, Vestn. MATI, 2007, no. 13 (85), pp. 60–66.Google Scholar
  9. 9.
    Sun, X.T., Jiang, Z.H., Xin, S.G., and Yao, Z.P., Composition and mechanical properties of hard ceramic coating containing, α-Al2O3 produced by microarc oxidation on Ti–6Al–4V alloy, Thin Solid Films, 2005, no. 471, pp. 194–199.Google Scholar
  10. 10.
    Cheng Yingliang, Peing Shaomei, Wu Xianguan, Jiu Hui Cao, Sheldon, P., and Thompson, G.E., A comparison of plasma electrolytic onidation of Ti–6Al–4V and Zircaloy-2 alloys in a silicate–hexamethphosphate electrolyte, Electrochim. Acta, 2015, no. 165, pp. 301–313.Google Scholar
  11. 11.
    Yerokhin, A.L., Nie, X., Leyland, A., and Matthews, A., Characterisation of oxide films produced by plasma electrolytic oxidation of a Ti–6Al–4V alloy, Surf. Coat. Technol., 2000, vol. 130, pp. 195–206.CrossRefGoogle Scholar
  12. 12.
    Wang, Y.M., Jia, D.C., Guo, L.X., Lei, T.Q., and Jiang, B.L., Effect of discharge pulsating on microarc oxidation coatings formed on Ti–6Al–4V alloy, Mater. Chem. Phys., 2005, vol. 90, pp. 128–139.CrossRefGoogle Scholar
  13. 13.
    Sundararajan, G. and Rama Krishna, L., Mechanisms underlying the formation of thick alumina coatings through the MAO coating technology, Surf. Coat. Technol., 2003, vol. 167, pp. 269–277.CrossRefGoogle Scholar
  14. 14.
    Bakovets, V.V., Polyakova, O.V., and Dolgovesova, I.V., Plazmenno-elektroliticheskaya anodnaya obrabotka metallov (Plasma Electrolytic Anodic Treatment of Metals), Novosibirsk: Nauka, 1990.Google Scholar
  15. 15.
    Rakoch, A.G., Dub, A.V., and Gladkova, A.A., Anodirovanie legkikh splavov pri razlichnykh elektricheskikh rezhimakh. Plazmenno-elektroliticheskaya nanotekhnologiya (Anodizing of Light Alloys under Various Electrical Conditions. Plasma Electrolytic Nanotechnology), Moscow: OOO “Staraya Basmannaya”, 2012.Google Scholar
  16. 16.
    Rakoch, A.G., Gladkova, A.A., Zayar, Linn., and Strekalina, D.M., The evidence of cathodic microdischarges during plasma electrolytic oxidation of light metallic alloys and micro-discharge intensity depending on pH of the electrolyte, Surf. Coat. Technol., 2015, no. 269, pp. 138–144.Google Scholar
  17. 17.
    Shelekhov, E.V. and Sviridova, T.A., Programs for X‑ray analysis of polycrystals, Met. Sci. Heat Treat., 2000, vol. 42, no. 8, pp. 309–313.CrossRefGoogle Scholar
  18. 18.
    Aver’yanov, E.E., Spravochnik po anodirovaniyu (Anodization Handbook), Moscow: Mashinostroenie, 1988.Google Scholar
  19. 19.
    Mamaev, A.I. and Mamaeva, V.A., Sil’notokovye mikroplazmennye protsessy v rastvorakh elektrolitov (Heavy-Current Microplasma Processes in Electrolyte Solutions), Novosibirsk, Sib. Otd. Ross. Akad. Nauk, 2005.Google Scholar
  20. 20.
    Suminov, I.V., Epel’fel’d, A.V., Lyudin, V.B., Krit, B.L., and Borisov, A.M., Mikrodugovoe oksidirovanie (teoriya, tekhnologiya, oborudovanie) (Microarc Oxidation (Theory, Technology, and Equipment)), Moscow, EKOMET, 2005.Google Scholar

Copyright information

© Allerton Press, Inc. 2019

Authors and Affiliations

  1. 1.National University of Science and Technology “MISiS”MoscowRussia

Personalised recommendations