Tribo-corrosion Performance of Plasma Sprayed Al2O3 on Aluminum Alloy for Thermal Barrier Coatings

Essam R.I. Mahmoud, Ali Algahtani

Keywords: 6082 Aluminium Alloy; plasma sprayed coating; erosion resistance; Microstructure; Wear resistance; polarization test

Issue I, Volume I, Pages 58-80

Aluminium alloys have attractions to be used for a wide range of applications due to its

lower density and the formation of passive film which provide corrosion protection. At high

temperature (more than 250 0C), the passive film may be destroyed, thermally corroded and it will

easily be failed by thermal fatigue failures. This work has investigated the enhancements of plasma

sprayed Al2O3 coating on the performance of 6082-T6 aluminium alloy surface against erosion

and corrosion test environments. The study investigates the macro/microstructure and the formed

phases of the plasma sprayed Al2O3 formed layer. The erosion resistance of the coated layer, in

particular, the effect of sand concentration and temperature variations to the aqueous slurry

impingement against material properties such as adhesion, ductility, and roughness were

investigated. In addition, a series of electrochemistry tests have been conducted to verify the

corrosion performance. As a reference, the un-coated 6082-T6 aluminium substrate was instigated

in all the experiments. The resulted showed that plasma sprayed Al2O3 coating layer had lamellar

structure of approximately 86% ?-Al2O3 and 14% ?-Al2O3 phases and contained many voids and

porosity. The coated layer shows good corrosion resistance at ambient temperature. At 80 ?C,

small amount of ions penetrations was recorded. The coated layer was completely removed after

polarizing the solution up to 400 mV for 24 hours. Although there was no stability of the current

in the coating during the polarization test, the coating shows lower corrosion current density under

static anodic polarization tests compared to the aluminium substrate indicates better corrosion

resistance. It has been shown that the erosion of the coated layer shows linear erosion rate. The

erosion rates observed for the coating in elevated temperature are much lower than aluminium

substrate. As a result, the erosion resistance of aluminium alloy can be highly improved by plasma

sprayed Al2O3 coating, especially at high temperature.

[1] H. Mraied, W. Cai, and A. A. Sagüés, “Corrosion resistance of Al and Al–Mn thin films,” Thin Solid

Film. Vol. 615, pp. 391-401, 2016.

[2] R.W. Revie, and H.H. Uhlig, “Corrosion and Corrosion Control: An Introduction to Corrosion Science

and Engineering, fourth edition, Wiley-Interscience, 2008, [Online]. Available: [Accessed: July. 15, 2018].

[3] A.W. Momber, T. Marquardt, “Protective coatings for offshore wind energy devices (OWEAs),” J.

Coat. Technol. Res. Vol. 15, pp. 13–40, 2018.

[4] A. López, R. Bayón, F. Pagano, A. Igartua, A. Arredondo, J.L. Arana, and J.J. González,

“Tribocorrosion behaviour of mooring high strength low alloy steels in synthetic seawater,” Wear Vol. 338-

339, pp. 1-10, 2015.

[5] G. A. El-Mahdy, and K.B. Kim, “AC impedance study on the atmospheric corrosion of aluminium

under periodic wet-dry conditions,” Electrochim. Acta. Vol. 49(12), pp. 1937-1948, 2004.


[6] M. Navaser, and M. Atapour, “Effect of Friction Stir Processing on Pitting Corrosion and Intergranular

Attack of 7075 Aluminum Alloy.,” J. Mater. Sci. Technol. Vol. 33 (2), pp. 155-165, 2017. doi:


[7] M. de Bonfils-Lahovary, L. Laffont, and C. Blanc, “Characterization of intergranular corrosion defects

in a 2024 T351 aluminium alloy.” Corros. Sci. vol.119, pp. 60-67, 2017. doi:10.1016/j.corsci.2017.02.020

[8] C.N. Panagopoulos, and E.P. Georgiou, “Corrosion and wear of 6082 aluminium alloy,” Tribol. Int. vol.

42(6), pp. 886-889, 2009.

[9] A. López-Ortega, R. Bayón, J.L. Arana, A. Arredondo and A. Igartua, “Influence of temperature on the

corrosion and tribocorrosion behaviour of high-strength low alloy steels used in offshore applications,”

Tribol. Int. vol. 121, pp. 341–352, 2018.

[10] H. Li, Z. Ke, J. Li, L. Xue, and Y. Yan, “An effective low-temperature strategy for sealing plasma

sprayed Al2O3-based coatings,” Journal of the European Ceramic Society 38, pp.1871–1877, 2018.

[11] P. Wang and J. P. Li, “The formation mechanism of the composited ceramic coating with thermal

protection feature on an Al-12Si piston alloy via a modified PEO process,” J. Alloys Compd. Vol. 682, pp.

357–365, 2016.

[12] J. Yamabe, S. Matsuoka and Y. Murakami, “Surface coating with a high resistance to hydrogen entry

under high-pressure hydrogen-gas environment,” Int. J. Hydrogen Energy vol. 38, pp. 10141–10154, 2013.

[13] R. Kromer, S. Costil, C. Verdy, S. Gojon, and H. Liao, “Laser surface texturing to enhance adhesion

bond strength of spray coatings – Cold spraying, wire-arc spraying, and atmospheric plasma spraying,”

Surf. Coat. Technol. Vol. 352, pp. 642–653, 2018.

[14] K. Yang, J. Rong, C.G. Liu, H.Y. Zhao, S.Y. Tao and C.X. Ding, “Study on erosion–wear behavior

and mechanism of plasma-sprayed alumina-based coatings by a novel slurry injection method,” Tribo. Int.

vol. 93, pp.29–35, 2016.

[15] H. Singh, and B. S. Sidhu, “Use of plasma spray technology for deposition of high temperature

oxidation/corrosion resistant coatings-a review,” Mater. Corros. VOL. 58(2), PP. 92-102, 2007. DOI:


[16] S. Kumar, A. Kumar, D. Kumar, and L. Jain, “Thermally sprayed alumina and ceria-doped-alumina

coatings on AZ91 Mg alloy,” Surf. Coat. Tech. vol. 332, pp. 533-541, 2007.


[17] D. Thirumalaikumarasamy, K. Shanmugam, and V. Balasubramanian, “Corrosion performances of

atmospheric plasma sprayed alumina coatings on AZ31B magnesium alloy under immersion environment,”

J. Asian Ceram. Soc. vol. 2(4), pp. 403-415, 2014.

[18] T. Q. Nakamura, G. Berndt, and C. Christopher "Effects of Pores on Mechanical Properties of Plasma-

Sprayed Ceramic Coatings," Journal of the American Ceramic Society, vol 83(3), pp. 578-584, 2000.

[19] S.H. Yao, “Comparative study on wear performance of traditional and nanostructured Al2O3-13 wt.%

TiO2 air plasma spray coatings,” Ceramics- Silikáty vol. 59, pp. 59–63, 2015.

[20] S. Beauvais, and V. Guipont, "Process-microstructure-property relationships in controlled atmosphere

plasma spraying of ceramics," Surf. Coat. Technol., vol. 183(2-3), pp. 204-11, 2004.

[21] R. G. Song, and C. Wang,"Microstructure and properties of Al2O3/TiO2 nanostructured ceramic

composite coatings prepared by plasma spraying," J. Alloys Compound., vol. 544(0), pp. 13-18, 2012.

[22] O. E.Abdel-Salam, M. A. Shoeib, and H. Ashour Elkilany, “Characterization of the hard anodizing

layers formed on 2014-T3 Al alloy, in sulphuric acid electrolyte containing sodium lignin sulphonate,”

Egyptian Journal of Petroleum, Article in Press,

[23] W. Tabakoff, and V. Shanov. “Erosion rate testing at high temp. for turbo machinery use.” Surf. Coat.

Technol. Vol. 76 – 77, Part I, pp. 75 –80, 1995.

[24] Q. Wang, C. S. Ramachandran, G. M. Smith, S. Sampath, “Sliding wear behavior of air plasma sprayed

Al2O3 coatings sealed with aluminum phosphate,” Tribo. Int., vol. 116, pp. 431–439, 2017.

[25] M. Daroonparvar, M. Yajid, N. Yusof, and H. Rad, “Fabrication and properties of triplex

NiCrAlY/nano Al2O313%TiO2/nano TiO2 coatings on a magnesium alloy by atmospheric plasma

spraying method,” J. Alloys Compd. Vo. 645, pp. 450–466, 2015.

[26] E. Colonetti, E. Kammer, and A. Junior, “Chemically-bonded phosphate ceramics obtained from

aluminum anodizing waste for use as coatings,” Ceram. Int. vol. 40, pp. 14431–14438, 2014.

[27] C. Sujaya, H. Shashikala, G. Umesh and A. C. Hegde, (2012). "Hardness and electrochemical

behaviour of ceramic coatings on Inconel." J. Electrochem. Sci. Eng. Vol. 2(1), pp. 19-31. 2012.

[28] M. Thammachart, “Corrosion Mechanisms of Chemically Bonded Composite Sol-Gel (CB-CSG)

Al2O3 Coated Systems in Aqueous Environment,” Edinburgh, Heriot-Watt University, PhD: 297, 2005.

[29] H. Lee, J. K. Singh, and M. A. Ismail, “An effective and novel pore sealing agent to enhance the

corrosion resistance performance of Al coating in artificial ocean water, Sci Rep. 2017; 7: 41935. Published

online 2017 Feb 3. doi: 10.1038/srep41935

[30] Y. Shi, B. Yang and P. K. Liaw, “Corrosion-Resistant High-Entropy Alloys: A Review,” Metals, vol.

7, pp. 43-61, 2017. doi:10.3390/met7020043.

[31] A. A. Olajire, “Corrosion inhibition of offshore oil and gas production facilities using organic

compound inhibitors - A review,” J. Mol. Liq. Vol. 248, pp. 775-808, 2017.


[32] G. A. Zhang, and L. Y. Xu, "Investigation of erosion-corrosion of 3003 aluminium alloy in ethylene

glycol-water solution by impingement jet system," Corrosion Science, vol. 51(2), pp. 283-290, 2009.

[33] A. Costa, and G. Macedonio, “Viscous heating in fluids with temperature-dependent viscosity:

implications form agma flows,” Nonlinear Processes in Geophysics, vol. (20), pp. 101-111, 2003.

[34] J.A. Curran, and T.W. Clyne, “Thermo-physical properties of plasma electrolytic oxide coatings on

aluminium,” Surf. Coat. Technol. Vol.199(2-3), pp. 168-176, 2005. doi:10.1016/j.surfcoat.2004.09.037.

[35] A. Nandi, and I. Lufman, "Erosion Related Changes to Physicochemical Properties of Ultisols

Distributed on Calcareous Sedimentary Rocks." Journal of Sustainable Development, vol. 5(8), pp.52-68,2012.