Dense ceramic coatings deposited by aerosol deposition for multilayered architecture towards thermal/environmental barrier coatings

Conference Dates

June 24-29, 2018


The demands for thermal/environmental barrier coatings (T/EBCs) have been increased as the operating temperature of gas turbines increased in harsh environment [1]. Multilayered and multifunctional coatings are required for advanced T/EBCs [2], varied from porous insulative layer to dense environmental barrier layer. Aerosol deposition (AD) method is a unique deposition method that enables the deposition of dense ceramic coatings with high adhesion strength without melting of injected powder based on room temperature impact consolidation (RTIC) phenomena [3-5]. Thus, it will be interesting to apply this process for T/EBC applications. However, in order to apply the AD method to these applications, the deposition rate and the ability of three-dimensional coverage should be improved. Mori et al. preliminary reported that the introduction of plasma assistance drastically improved the deposition rate for lead zirconate titanate [6]. Thus, it would be worth to try to enhance aerosol deposition by introduction of plasma assistance [7]. The use of mesoplasma flow, which is transitional state from thermal plasma to low-pressure plasma, is the key to the deposition [8]. Fine powder of 8-wt% yttria-stabilized zirconia was sprayed by an rf-inductively coupled plasma at a reduced pressure. The effect of plasma assistance was confirmed at the power input of several kilowatts, which was much smaller compared to conventional plasma spray. Coatings with uniform thickness of 5-20 µm was obtained. The Vickers hardness of the coating reached to 1200 HV. This coating will be useful for the architecture of multilayered advanced T/EBCs.


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[2] V. Viswanathan et al., J. Am. Ceram. Soc., 97 (2014) 2770-2778.

[3] J. Akedo and M. Levedev, Jpn. J. Appl. Phys. Part 1, 38 (1999) 5397-5401.

[4] J. Akedo, J. Am. Ceram. Soc. 89 (2006) 1834-1839.

[5] J. Akedo, J. Therm. Spray Technol. 17 (2008) 181-198.

[6] M. Mori et al., Proc. IEEE Int. Symp. Appl. Ferroelectric. 1-2 (2007) 454-456.

[7] A. Vardelle et al., J. Therm. Spray Technol. 25 (2016) 1376-1440 (J. Akedo and K. Shinoda, Section 2.2, 1379-1383).

[8] T. Yoshida, Pure Appl. Chem. 78 (2006) 1093-1107.

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