Durability of Amorphous and Crystalline BMAS Thermal Barrier Coatings Produced by Plasma Spraying

0465123 - ÚFM 2018 RIV CH eng C - Conference Paper (international conference)
Čelko, L. - Jech, D. - Dvořák, K. - Šulák, Ivo - Klakurková, L. - Obrtlík, Karel
Durability of Amorphous and Crystalline BMAS Thermal Barrier Coatings Produced by Plasma Spraying.
Materials Structure & Micromechanics of Fracture VIII. Zürrich: Trans Tech Publications, 2017 - (Šandera, P.), s. 383-386. Solid State Phenomena, 258. ISBN 978-3-03835-626-4. ISSN 1662-9779.
[MSMF8. International Conference on Materials Structure and Micromechanics of Fracture /8./. Brno (CZ), 27.06.2016-29.06.2016]
R&D Projects: GA ČR(CZ) GA15-20991S
Institutional support: RVO:68081723
Keywords : Burner-Rig Test * Coating Failure * Plasma Spraying * Thermal Barrier Coating * Powder Processing
OECD category: Coating and films

Barium-Magnesium-Aluminium-Silicate (BMAS) powder was produced from a mixture of initial compounds BaO–MgO–Al2O3–SiO2 by means of solid state synthesis at the temperature of 1200 °C for 3 hours in a laboratory furnace. Synthetized powder was crushed into the fraction of 15-45 micrometer in a planetary ball mill. Thermal barrier coating system consisting of CoNiCrAlY (bond coat) and BMAS (top coat) was sprayed by atmospheric plasma spray technique onto the polycrystalline nickel-based superalloy substrate. During plasma spraying process, the BMAS underwent phase transformation and the amorphous phase within the top coat was produced. Therefore, after the spraying, several samples were crystallized via annealing in a furnace (4 hours at 1200 °C or 24 hours at 1000 °C) or by subjecting them to several passes of plasma jet. Both samples with an amorphous phase and fully-crystallized samples were subjected to the fire in a burner-rig test (propane-oxygen flame, single 3 + 3 minute cycle), where the top coat reached the temperature of 1150 °C. Top coat failure occurred during the cooling period due to the transformation of the amorphous phase into the crystalline one and/or due to the difference in thermal conductivity and expansion between the top coat and the bond coat.
Permanent Link: http://hdl.handle.net/11104/0271155