Gas turbine processes are a well developed mechanisms for converting chemical potential energy in form of fuel, to thermal energy and then to mechanical energy for example used in aircraft or generating plants or for generating electric power. Today the most suitable solution to improve the efficiency of gas turbine engines appears to be an increase of higher operating temperatures. The metallic materials used in gas turbine engines have nearly reached their upper limits of thermal stability. In the hottest regions of modern gas turbine engines, metallic materials are used at temperatures above their melting points. They can only resist because of air cooling, but as a negative side effect excessive air cooling reduces their efficiency. Therefore, there have been extensive developments of thermal barrier coatings (TBCs). The TBCs have shown great potential in improving the durability and efficiency of gas turbine engines by allowing an increase of the turbine's inlet temperature and by reducing the amount of cooling air at hot-section components. Zirconia offers the properties mentioned before plus a high coefficient of thermal expansion, that is a primary reason for the success as a thermal barrier material on metallic substrates. TBCs have been deposited by several techniques including thermal spraying, sputtering and electron beam physical vapour deposition (EB-PVD). The EB-PVD is the currently preferred technique for demanding applications because of it's special coating structure. Depending on several parameters the ceramic coatings have a columnar grain microstructure that consists of small columns separated by gaps which become smaller inside the coating. These gaps allow the important substrate expansion without the cracking or the spalling of the coat. The main problem of zirconia yttria stabilized thermal barrier coatings (YPSZ) deposited with EB-PVD is a sinter process above 1200 deg C when the columns loose their property of expansion tolerance due to a closing of their gaps. This process leads to a very fast fatigue of the thermal barrier coatings. For that reason extensive developments of new thermal barrier coatings were needed that allow an increase of turbine inlet temperatures. Investigations on some materials with perovskite, spinelle and pyrochlore structure have shown a great potential of Lanthanum zirconate (pyrochlore) as thermal barrier coating. This ceramic material has a cubic crystal structure. The project introduced today the Lanthanum zirconate coatings were deposited on Ni base Inconel Alloy 600 with a EB-PVD coating device from Leybold. The coatings were characterized by the following analytical methods: x-ray diffraction (XRD), scanning-electron microscopy (SEM), electron dispersive diffraction (EDX), Nanoindentation and thermo-cycling-test.
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