High Temperature Unique Low Thermal Conductivity Thermal Barrier Coating (TBC) Architectures (Phase II STTR)
- UES, Inc., Dayton, OH (United States)
- Pennsylvania State Univ., University Park, PA (United States)
For increased efficiency of Integrated Gasification Combined Cycle (IGCC) power plants, higher gas turbine inlet temperature (> 1300ºC) is needed. At such high temperature the durability of metallic components of the gas turbine is a concern. High gas temperature could lead to deleterious effects on the metallurgy and chemistry of the components whereas high gas pressure together with particle impact could lead to erosive damage making the engine components less durable. Currently, the durability of the turbine engine components is achieved by the thermal barrier coatings (TBCs) consisting of yttria stabilized zirconia YSZ. However, YSZ is not adequate for required higher temperature applications. TBC materials such as rare earth zirconates having high temperature stability, lower thermal conductivity and lower sintering rate do exist. However, such materials possess very low toughness and thereby exhibit reduced erosion durability. The propose of this research was to enhance the toughness and hence the erosion durability of existing high temperature TBC materials while maintaining other required characteristics such as high temperature phase stability, low thermal conductivity and sintering rate. In this STTR program, gadolinium zirconate (Gd2Zr2O7:GZO) a well-known high temperature TBC material, having high temperature thermal stability, low thermal conductivity and low sintering rate but much lower toughness was selected as the base material. A systematic study was conducted to examine the notion of integrating GZO with tougher materials such as t’ low k and perovskite gadolinium aluminate (GdAlO3:GAP) in composite TBC design architectures to enhance erosion durability. Novel feed stock powders of composite GZO-t’ low k having presumed intrinsic toughness were synthesized. The feed stock powders were utilized to fabricate tougher GZO-t’ low k composite TBCs using atmospheric pressure plasma spray process (APS). The fabricated TBCs were characterized in terms of phase, microstructure, thermal conductivity, high temperature phase stability and thermal cyclic life. It is shown that the composite GZO-t’ low k TBCs fabricated with spray dry powder exhibits the desired characteristics for higher temperature applications. APS TBCs of composite GZO-GAP were also fabricated and their relevant characteristics were evaluated. The potential of composite GZO-GAP TBCs for higher temperature applications was also demonstrated.
- Research Organization:
- UES, Inc., Dayton, OH (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- SC0004356
- OSTI ID:
- 1461965
- Type / Phase:
- STTR (Phase IIB)
- Report Number(s):
- DE-SC0004356-3; UES P986
- Country of Publication:
- United States
- Language:
- English
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