Ultra-High Temperature Thermal Barrier Coatings
- Univ. of Connecticut, Storrs, CT (United States)
- HiFunda LLC, Salt Lake City, UT (United States)
In this project, HiFunda LLC worked with the University of Connecticut (UConn) to demonstrate an attractive option for thermal barrier coatings (TBCs), namely yttrium aluminum garnet (YAG), which was well known to have proven thermal stability and excellent high-temperature mechanical properties. YAG and other higher temperature TBCs have not been used to date because they exhibit inadequate durability, resulting from (a) poor erosion resistance and (b) greater thermal expansion mismatch strains compared to 7YSZ. UConn had previously demonstrated that the solution precursor plasma spray (SPPS) process could produce a durable 7YSZ TBC resulting from a highly strain tolerant microstructure, consisting of through-coating-thickness vertical cracks. HiFunda/UConn reasoned at the start of Phase I that such a strain-tolerant microstructure could produce durable, higher temperature TBCs. The Phase I work demonstrated the feasibility of that concept and of SPPS YAG TBCs. The Phase II work demonstrated that SPPS YAG coating possessed the necessary range of properties to be a viable high temperature TBC, including cyclic durability and reduced elevated temperature thermal conductivity. The SPPS YAG TBCs were shown to have the potential to be used at temperatures 200°C higher than APS YSZ, based on thermal stability, sinter resistance, and CMAS resistance. The overall technical objectives of this Phase 2A project were to further improve the commercial viability of SPPS by improving their performance capabilities and manufacturing economics. The improved performance capability was to be achieved through: (1) further reductions in thermal conductivity, which allows higher gas temperatures and/or thinner coatings to achieve similar gas temperatures; and (2) improved resistance to calcium magnesium alumnoslicate (CMAS) attack of the TBCs, which can yield improved lifetimes. The improved thermal conductivity and CMAs resistance was to be accomplished through compositional and microstructural optimization. Finally, the key metrics to improve the process economics were increased deposition rate and efficiency. In addition to these technical objectives, there were commercialization objectives of getting key commercialization partners to evaluate and qualify the SPPS YAG technology independently so that the technology readiness level (TRL) of the technology could be sufficiently advanced to facilitate Phase III strategic partnerships, leading to eventual commercialization consistent with the overall objectives of the DOE SBIR/STTR program. All the Phase 2A goals were successfully achieved.
- Research Organization:
- HiFunda LLC, Salt Lake City, UT (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- SC0007544
- OSTI ID:
- 1409355
- Type / Phase:
- STTR (Phase IIA)
- Report Number(s):
- DOE-HIFUNDA-SC0007544-2B
- Country of Publication:
- United States
- Language:
- English
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