The development of advanced gas turbine stimulates the preparation of high performance thermal barrier ceramic coatings with lamellar microstructure via thermal spray approaches. The decrease of lamellar splat thickness and the splat/splat bonding ratio, together with other coating microstructure design, would be effective directions in future. Up to now, the analytical model of the heat conduction behavior is mainly based on the three dimensional model of thermal contact resistance. However, the assumption of the three dimensional model would be far away from the real coating microstructure, especially with the decrease of lamellar splat thickness and the splat/splat bonding ratio. In addition to the two-flux regions analytical model proposed by Clyne, a two dimensional analytical model was proposed to understand the heat flux in the coatings, in comparison to or together with the conventional three dimensional model. Results showed that the heat conduction resistance was underrated by the three dimensional model, compared to the two dimensional model. The effects of the microstructural parameters, including splat thickness, splat bonding ratio and unit size, on the total thermal resistance was discussed in this study. Based on the two dimensional model, it is quite powerful to increase the thermal resistance by increasing unit size and decreasing splat bond ratio and splat thickness.
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