Investigation on Improved-Durability Thermal Barrier Coatings

Abstract

Concurrent with the development of new generation of gas turbines, many attempts have been made to introduce advanced thermal barrier coatings with lower thermal conductivity and higher temperature stability. Most of the research to improve TBCs performance are based on two general approaches: structural modifications and chemical modifications. In most cases, the improvements in some properties are at the expense of loss of some other properties. Changing in the TBCs architecture and the application of multilayer coatings, consisting of layers with engineered properties based on the requirements, is a solution to achieve a combination of desired properties. In all of these development methods it is to be understood that the principle is reducing the possibility of formation of cracks, but, once formed, all such cracks can grow under and thermal cycles and eventually lead to coating delamination and spallation. Self-healing is the most precious phenomenon to overcome this problem.