CCS and Power Systems
Advanced Energy Systems - Hydrogen Turbines
Low Thermal Conductivity, High Durability Thermal Barrier Coatings for IGCC Environments
Performer: University of Connecticut
Project No: FE0007382
- SPPS YSZ TBCs were deposited with a thermal conductivity of 0.6 watts per meter kelvin, a 50 percent reduction compared to air plasma spray (APS) YSZ. This breakthrough accomplishment achieved the prime goal of the program by introducing planar arrays of porosity, called inter-pass boundaries (IPBs). The IPBs are a unique microstructural feature of the SPPS process. Other low thermal conductivity TBCs rely on expensive rare-earth elements and exhibit poorer fracture toughness and erosion resistance (Figure 2).
- Preliminary thermal cycling tests were performed and showed that SPPS YSZ with IPBs had a cyclic life equal to that of standard SPPS YSZ TBCs and better than that of APS YSZ TBCs.
- A preliminary erosion test on low conductivity YSZ TBCs with IPBs showed erosion resistance as good as or better than standard YSZ TBCs (Figure 4).
- Successfully created a CMAS precursor solution suitable for use in subsequent CMAS testing.
- Successfully applied a protective surface layer consisting of a rare earth element based CMAS resistant higher temperature material (Figure 3).
- Purchased and installed a tube furnace for future high humidity testing.
- Successfully sprayed new YSZ-based TBCs with additional contents of Alumina and Titanium oxide, aiming to achieve advanced CMAS resistance as reported in Nitin Padture’s work. The thermal conductivity of these new TBCs was measured using laser-flash (Figure 5).
- Demonstrated that calculated thermal conductivity based on micrographs are not reliable and replaced this method with laser flash measurements.