Zirconia thermal barrier coatings

A.J. Slifka, B.J. Filla, J.M. Phelps, C.C. Berndt and G. Bancke, Thermal Conductivity of a Zirconia Thermal Barrier Coating, submitted to Journal of Thermal Spray Technology. 

Viazzi C., Bonino J. P., Ansart F. 2006. Synthesis by sol-gel route and characterization of yttria stabilized zirconia coatings for thermal barrier applications. Surface Coatings Technology 201, 3889-3893. 

Figure 7.41 Porous Y-stablllzed zirconia thermal barrier coating (TBC) on top of a dense NiCrAlY bond coat covering the TI6AI4V alloy substrate of a gas turbine blade (Heimann et al, 1991).

Skandan, G. Yao, R. Kear, B. Qiao, Y. Liu, L. Fischer, T. (2001). Multimodal Powders A New Class of Feedstock Material for Thermal Spraying of Hard Coatings. Scripta Materialia, Vol. 44, No. 8-9, pp. 1699-1702, ISSN 13596462 Soltani, R. Coyle, T. W. Mostaghimi, J. (2008). Microstructure and Creep Behavior of Plasma-Sprayed Yttria Stabilized Zirconia Thermal Barrier Coatings. Journal of Thermal Spray and Technology, Vol. 17, No. 2, pp. 244-253, ISSN 15441016... 

Fir. 13 Cross section illustrating the strain-tolerant columnar Z1O2 micro- structure of EB/PVD zirconia thermal barrier coatings. Source Ref 62... 

The addition of cerium oxide, for example, to zirconia produces a material with exceptional toughness and good strength [29], Cerium oxide-doped zirconia is used also in thermal barrier spray coatings on metal surfaces(30]. 

Kokini, K., Takeuchi, Y. R., and Choules, B. B., "Surface Thermal Cracking of Thermal Barrier Coating Owing to Stress Relaxation Zirconia vs. Mullite," Surface and Coatings Technology, Vol. 82, pp. 77-82, 1996. 

Zirconia (Zr02) is an extremely versatile ceramic that has found use in oxygen pumps and sensors, fuel cells, thermal barrier coatings, and other high-temperature applications, all of which make use of the electrical, thermal, and mechanical properties of this material. Proof of the interest and usefulness of zirconia can be seen from the voluminous literature found on this material. This chapter is intended to provide a concise summary of the physical and chemical properties of all phases of zirconia that underlie the appropriate engineering applications. 

Zirconia is a very interesting material in ceramic industry, with exceptional electrical, thermal (Chap. 23), and mechanical properties (Chap. 22 Mechanical characterization of aerogels) allowing its use in fuel cells, thermal barrier coatings, oxygen sensors, and many other high-temperature applications. In all these applications, this material is doped with other oxides to stabilize the tetragonal or cubic phase at low temperatures. 

Thermal Barrier Coatings (TBCs) The combustion temperatures of car engines and aerospace gas turbines are severely limited by the inability of common metalUc construction materials to withstand temperatures in excess of approximately 1000 °C. However, the appUcation of thermal barrier coatings based on stabilized zirconia represents one way of increasing the combustion temperature, and hence the thermodynamic efficiency and environmental compatibility by reducing the amount of hydrocarbons expelled in the exhaust gases. 

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