Modelling of thermal conductivity of porous materials: application to thick thermal barrier coatings

• Published in: Journal of the European Ceramic Society Vol. 24; no. 9; pp. 2657 - 2667
• Main Authors: Cernuschi, F., Ahmaniemi, S., Vuoristo, P., Mäntylä, T.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.2004; Elsevier
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Chemistry; Colloidal state and disperse state; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Functional applications; General and physical chemistry; Miscellaneous; Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves; Physics; Plasma spraying; Porosity; Powders; Technical ceramics; Thermal barrier coatings; Thermal conductivity; Transport properties of condensed matter (nonelectronic); ZrO 2; ZrO 2; Thermal barrier coatings; Thermal conductivity; Porosity; Plasma spraying; Functional applications; Thick coatings; Porous materials; Theoretical study; Stabilized zirconia; High temperature; Oxide ceramics; Fabrication; Thermal properties; Composite materials; Plasma arc spraying; Technical ceramics; Modelling; Zirconium Oxides
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2003.09.012

Modelling of thermal conductivity of two and three phase composite materials is used to determine the thermal conductivity of thick porous zirconia based thermal barrier coatings for use in high temperature applications. These coatings, depending on the deposition technique and process parameters exhibit different degrees of porosity. The porosity of the coating has an affect on thermal properties in completely different ways depending on the morphology and the orientation of the pores dispersed within a continuous matrix. In this work air plasma sprayed coatings have been considered. The experimental results were successfully compared to the modelled thermal conductivities. In the model the effects of porosity were taken into account considering the shape, orientation and volumetric percentage of pores. Image analysis and mercury porosimetry was used in experimental porosity determination.