Ultra-High Temperature Thermal Barrier Coatings

The US Department of Energy has a stated goal to increase the energy efficiency of turbines, and one well recognized method of achieving this is through the use of ceramic thermal barrier coatings (TBCs). However, state of the art zirconia-based TBCs have a temperature limit of about 1200oC, and new TBC materials that can operate at elevated temperatures of 1300oC and above are needed to continue to push turbine operating temperatures further up and achieve the associated energy efficiency gains. Statement of how this problem or situation is being addressed HiFunda LLC and the University of Connecticut (UConn) will team to demonstrate an advanced thermal barrier coating (TBC), consisting of a new top coat chemistry of yttrium aluminum garnet (YAG), that has lower thermal conductivity, higher use temperature, greater erosion resistance, and improved sintering resistance compared with the widely used yttria partially stabilized zirconia (YSZ) top coats. Phase I Accomplishments In Phase I, HiFunda LLC and UConn successfully demonstrated the capability of making YAG thermal barrier coatings with a unique, highly desirable microstructure using the solution precursor plasma spray process (SPPS). This represents a significant advance in that it was the first successful demonstration of fabricating highly durable, thick TBCs with at least a 200oC higher surface operating temperature, which also has lower thermal conductivity, improved thermal cycling performance and reduced density. Planned Phase II Effort In Phase II, HiFunda and UConn will demonstrate the substantial technical advantages and favorable economics of SPPS YAG TBCs so as to facilitate widespread adoption by engine manufacturers and coating suppliers. The project team will (1) demonstrate needed durability of SPPS YAG TBCs that engine manufacturers need prior to adopting advanced TBCs and (2) develop and demonstrate a robust, economical process. Process optimization and scale-up will conducted at a HiFunda incubator facility at UConn. HiFunda/UConn will team with, and have received significant cost share commitments from a number of major engine manufacturers and coating suppliers. Commercial Applications and Other Benefits These novel TBCs can be an enabling technology for highly efficient next generation gas turbines and upgrades to existing ones. By partnering with leading US gas turbine equipment manufacturers, the proposed technology can be accelerated into the market with the result of reducing energy costs, helping to maintain US leadership in the global gas turbine market, and reducing greenhouse gas emissions.