Abstract
In this study, substrates of Inconel 738 LC superalloy coupons were first sprayed with a NiCoCrAlY bondcoat and then with a ceria and yttria stabilized zirconia (CYSZ; ZrO 2-25 wt%CeO 2-2.5 wt%Y 2O 3) topcoat by air plasma spraying (APS). Hot corrosion studies of plasma sprayed thermal barrier coatings (TBCs) were conducted in 45 wt%Na 2SO 455 wt%V 2O 5 molten salt at 1000 °C for 30 h. The results showed that the coating defects, such as pores and microcracks play important roles as effective paths for the salt penetration in hot corrosion. Based on the results, the reaction between molten salt and stabilizers of zirconia (Y 2O 3 and CeO 2), the formation of YVO 4, CeVO 4 and CeO 2 crystals, the detrimental phase transformation of zirconia from tetragonal to monoclinic due to the depletion of stabilizers and finally, the creation of stresses were recognized to be in the degradation mechanism of CYSZ ceramic coatings in the presence of molten sulfate-vanadate salt.
| Original language | English |
|---|---|
| Pages (from-to) | 6613-6620 |
| Number of pages | 8 |
| Journal | Ceramics International |
| Volume | 38 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - Dec 2012 |
| Externally published | Yes |
Free Keywords
- Air plasma spraying
- CYSZ
- Hot corrosion
- Thermal barrier coating
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Materials Chemistry