| Thermal design and management play critical roles in thermal spray coating systems, and it is important to assess the properties directly from the coating microstructure. In this dissertation, a combined image analysis and finite element method approach is developed to assess thermal conductivity from high-resolution scanning electron microscopy images of the coating microstructure. Images are analyzed with a collection of image processing algorithms to reveal the microscopic coating morphology. The effective thermal conductivity is then simulated using finite element codes in two methods: steady-state and transient. Results are found to be in good agreement with experimental values, obtained using the flash method.;Finally, based-on the above thermal property assessment techniques, the overall thermal management of thermal spray coating system is investigated, by analyzing the thermal spray coatings annealed in various conditions, and then the long-term thermal performance can be predicted.;Keywords. thermal conductivity, thermal diffusivity, thermal spray coatings, thermal barrier coatings, image analysis, finite element analysis.;Moreover, experimental issues are addressed for measurement of thermal property of thermal spray coatings. The flash method for thermal diffusivity determination is evaluated for heterogeneous materials. Result shows that for highly heterogeneous materials, there are significant errors for standard flash methods on effective thermal conductivity; however, the errors for thermal spray coatings are negligible. The results are used for validation and correction to the standard flash method. |
