Thermal barrier coating applications re known for thermally loaded combustion process components for decades. From the early beginning, science and industry worked on solutions about how to combine such different materials properties as from superalloy metals and ceramic thermal insulators. While partially stabilized zirconia became very early the material standard, thermal spraying and electron beam physical vapor deposition were even in the early 90's considered as competing technologies.

This paper reviews why EB-PVD is the actual choice for the latest state-of-the-art components and will attempt to summarize the major roadblocks for thermal barrier technology on its way to become a fully prime reliant, designed-in feature.

Some potential answers for today's technical issues will be discussed with respect to their ability to shift TBS-applications to the next level of reliability within the various engine environments.

Zirconia thermal barrier coatings are well introduced in the turbine manufacturing industry because they ensure extended lifetimes of special components like turbine blades. Compared with other techniques EB-PVD proceses are best suited for the deposition of turbine blades with regard to the layer properties. Therefore EB-PVD coaters for turbine blades are becoming increasingly interesting.

The coating costs per component are mainly dependent on a highly productive solution for the deposition task. Thus the EB-PVD process guidance has to be optimized in order to meet the productivity requirements of the manufacturers. This includes the requirement of high deposition rates, large deposition areas, long time stable production cycles as well as a matched duration of preheating, deposition and cooling down per charge.

Modern EB-PVD solutions to be introduced allow deposition rates on blades up to 7µm/min. Consequences for the technological process guidance and plant design concerning long time stable coating cycles with high productivity will be discussed.

In order to improve the engine output and the efficiency of gas turbines, optimized thermal barrier coatings (TBCs) are required to protect the metallic components at high temperatures. In common TBC-systems, consisting of a Ni-base alloy substrate/MCrAlY-bond coat/ZrO₂7wt.% Y₂O₃top coat, an oxide layer grows at the interface bond coat/ceramic under high temperature service, which limits the life of these coatings.

In this paper the oxidation resistance of a new triplex TBC-system, consisting of a CoNiCrAlY-bond coat/Pt-modified aluminide coating/ZrO₂7wt.% Y₂O₃top coat is compared with that of a common TBC-system. The as-coated Pt-aluminide coating consists of an outer region of PtAl₂+ (CoNiPt)Al followed by a single phase layer of (CoNiPt)Al. The results of the oxidation tests at 1273K, 1323K and 1373K in air show excellent oxidation resistance of the triplex TBC-systems, which increases with the Pt-aluminide coating thickness. In particular, a 28 µm thick Pt-aluminide coating allows the thickness of the oxide layers to be reduced up to 70% compared to the common TBC after 500h at all examined temperatures. After heat treatment the coating systems were investigated by SEM, EDX and X-ray analysis. Annealing tests with Al₂O₃-powder indicate which mechanism is responsible for the improved oxidation resistance of platinum additions. Platinum is evidently capable of decomposing aluminumoxide into aluminum and oxygen at temperatures above 1173K .