Abstract
The performance of thermal barrier coating (TBC) specimens with superalloy 1483 and X4 substrates and high velocity oxy fuel (HVOF)-NiCoCrAlYHfSi bond coatings was evaluated in dry and wet air in 1h furnace cycles at 1100°C. Compared to a prior study of NiCoCrAlYHfSi bond coatings, the HVOF bond coatings were rougher Ra=8μm, closer to commercial HVOF coatings. For TBC coatings on the X4 substrates cycled in air with 10% water vapor, increasing the roughness from Ra=5 to 8μm had little effect on the average TBC lifetime. The presence of 10% water vapor reduced the average TBC lifetime for 1483 by 13%, however, in both wet and dry conditions, the lifetimes for this substrate were 30-50% below those observed for X4 substrates. This may be attributed to the lower Al content and higher Ti content in 1483. Roughness and residual stress in the alumina scale were measured on specimens without a ceramic top coating, but no effects were observed due to the change in substrate or the addition of water vapor.
| Original language | English |
|---|---|
| Pages (from-to) | 65-70 |
| Number of pages | 6 |
| Journal | Surface and Coatings Technology |
| Volume | 237 |
| DOIs | |
| State | Published - Dec 25 2013 |
Funding
The authors would like to thank G. Garner, T. Lowe, T. Jordan and H. Longmire for assistance with the experimental work at ORNL and K. Murphy at Howmet and A. Kulkarni at Siemens for providing the superalloys. The specimens were coated at Stony Brook University. P. F. Tortorelli provided helpful comments on the manuscript. This research was sponsored by the U.S. Department of Energy , Office of Coal and Power R&D , Office of Fossil Energy (R. Dennis program manager).
| Funders | Funder number |
|---|---|
| Office of Coal and Power R&D | |
| U.S. Department of Energy | |
| Office of Fossil Energy |
Keywords
- Bond coating
- HVOF
- Lifetime
- Oxidation
- Roughness
- TBC