High Purity Thermal Barrier Coating Systems

Thermal barrier coating systems have been used for some time in gas turbine engines. These coatings help prolong the life of critical engine components by protecting them from the harsh environment that they perform in. A typical thermal barrier coating system currently utilizes a stabilized Zirconia for its thermal protection.  Commercially available Zirconia materials for these coatings can have a maximum impurity level of up to six percent-by weight. This paper evaluates the use high purity stabilized Zirconia. Different structures from both chemistries are evaluated by both isothermal and dynamic temperature exposure tests.  The laboratory test results demonstrate that coating life improvements are possible with the use of high purity Zirconia. This is demonstrated by both phase stability and increased test life at higher test temperatures.