Publication detail

Microstructural Changes of Plasma Sprayed Al2O3-SiO2-ZrO2 Thermal Barrier Coatings After Isothermal Exposure

JECH, D. ČELKO, L. KLAKURKOVÁ, L. ŠVEJCAR, J.

Original Title

Microstructural Changes of Plasma Sprayed Al2O3-SiO2-ZrO2 Thermal Barrier Coatings After Isothermal Exposure

Type

abstract

Language

English

Original Abstract

Eutectic ceramic Al2O3-ZrO2-SiO2 also termed Eucor (as a top coat) and CoNiCrAlY (as bond coat) coatings were sprayed onto the surface of newly developed fine-grained cast polycrystalline nickel-based superalloy Inconel 713 LC by means of water stabilized plasma (WSP) and atmospheric plasma spraying (APS) respectively. After the spraying were all the samples annealed at the temperature of 950 C for 10 hours, and followed separately by isothermal heat treatment at 900 C for 10, 50, 100, 200 and 500 hours in ambient atmosphere. Eucor microstructural changes and as well the changes at top coat/bond coat interface were investigated by means of scanning electron microscope with an energy dispersive microanalyzer. The microstructure of APS CoNiCrAlY bond coat consisted of flattened splats, partially unmelted particles and oxides, which were formed across splats interfaces in interaction with ambient atmosphere during spraying. The top coat near-eutectic composition allowed to form Eucor amorphous structure originated during rapid solidification. Nanocrystallization of eutectic from amorphous phase occurred during first step of above mentioned heat treatment and the nanoparticles with average size of 10 nm were formed within the ceramic top coat. Influence of shot-time and long-time isothermal exposure on nanoparticles coarsening and interactions at bond-coat/ top coat interface were studied. It was found, that only slight coarsening ranging up to 20 nm occurred within the top coat, and thermally grown oxide (TGO) layer formed and grew in thickness across the bond coat/top coat interface.

Keywords

Thermal Barrier Coatings, Plasma Spraying, Isothermal heat treatment, Amorphous phase and nanocrystallization, Electron microscopy

Authors

JECH, D.; ČELKO, L.; KLAKURKOVÁ, L.; ŠVEJCAR, J.

Released

12. 3. 2014

Publisher

SAMPE

Location

Paris

BibTex

@misc{BUT109502,
  author="David {Jech} and Ladislav {Čelko} and Lenka {Klakurková} and Jiří {Švejcar}",
  title="Microstructural Changes of Plasma Sprayed Al2O3-SiO2-ZrO2 Thermal Barrier Coatings After Isothermal Exposure",
  year="2014",
  publisher="SAMPE",
  address="Paris",
  note="abstract"
}