New thermal barrier coating systems with a graded ceramic coating

摘要

Graded and layered plasma-sprayed La_2Zr_2O_7 / YSZ thermal barrier coating systems have been developed. The tests in a thermal cycling facility at different surface and bondcoat temperatures showed for both types of systems a significant improvement of life time compared to the single layer La_2Zr_2O_7 system. The cyclic life of the graded system was comparable to the one of YSZ coatings. The layered systems had at surface temperatures above 1300°C by at least a factor of 2 higher life time than the standard YSZ system. These results clearly show the high performance of the new systems.