Abstract
A Pt-enriched γ+γ′ two-phase coating was applied to directionally-solidified Ni-based superalloy René 142 substrates with three different Hf levels (0.02, 0.76, and 1.37 wt.%). The coating was prepared by electroplating a thin layer of Pt on the superalloy followed by a diffusion treatment. The as-deposited coating exhibited a γ+γ′ two-phase microstructure with a major composition of Ni-16Al-18Pt-7Cr-9Co (in at.%) along with some incorporation of refractory elements from the substrates. Cyclic oxidation testing at 1100 °C in air indicated improved oxidation resistance of the René 142 alloys with the Pt-enriched γ+γ′ coatings. In addition, the oxidation resistance of both uncoated and coated alloys was proportional to the Hf content in the substrate. Compared with the single-phase β-(Ni,Pt)Al coating, slightly higher mass gains and localized spallation were observed on the γ+γ′ two-phase coating, which might be due to the segregation of refractory elements and high sulfur levels in these superalloy substrates.
| Original language | English |
|---|---|
| Pages (from-to) | 1259-1263 |
| Number of pages | 5 |
| Journal | Surface and Coatings Technology |
| Volume | 200 |
| Issue number | 5-6 |
| DOIs | |
| State | Published - Nov 21 2005 |
Funding
The authors acknowledge K.M. Cooley, G.W. Garner, L.D. Chitwood, K.S. Reeves, and L.R. Walker at ORNL and Y.Q. Wang at Tennessee Technological University (TTU) for assisting with the experimental work, and P. F. Tortorelli at ORNL for reviewing the manuscript. This research was sponsored by the U.S. Department of Energy, Fossil Energy Advanced Materials Research Program, under contract DE-AC05-00OR22725 with UT-Battelle LLC and subcontract 4000032193 with TTU.
| Funders | Funder number |
|---|---|
| Fossil Energy Advanced Materials Research Program | DE-AC05-00OR22725 |
| UT-Battelle LLC | 4000032193 |
| U.S. Department of Energy |
Keywords
- Bond coat
- Oxidation
- Pt-enriched coating
- René 142
- γ+γ′ Two-phase coating