Microstructural characterization of GZ/CYSZ thermal barrier coatings after thermal shock and CMAS plus hot corrosion test

GOK M. G., Göller G.

JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, vol.37, no.6, pp.2501-2508, 2017 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 37 Issue: 6
  • Publication Date: 2017
  • Doi Number: 10.1016/j.jeurceramsoc.2017.02.004
  • Journal Name: JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.2501-2508
  • Keywords: Gd2Zr2O7, Thermal barrier coating, Thermal shock, CMAS, Hot corrosion, CYCLING BEHAVIOR, RESISTANCE, GD2ZR2O7, INFILTRATION, DAMAGE, GLASS, ASH, AIR
  • Istanbul Technical University Affiliated: Yes

Abstract

In this study, first, Gd2Zr2O7/ceria-yttria stabilized zirconia (GZ/CYSZ) TBCs having multilayered and functionally graded designs were subjected to thermal shock (TS) test. The GZ/CYSZ functionally graded coatings displayed better thermal shock resistance than multilayered and single layered Gd2Zr2O7 coatings. Second, single layered YSZ and functionally graded eight layered GZ/CYSZ coating (FG8) having superior TS life time were selected for CMAS + hot corrosion test. CMAS + hot corrosion tests were carried out in the same experiment at once. Furthermore, to generate a thermal gradient, specimens were cooled from the back surface of the substrate while heating from the top surface of the TBC by a CO2 laser beam. Microstructural characterizations showed that the reaction products were penetrated locally inside of the YSZ. On the other hand, a reaction layer having similar to 6 mu m thickness between CMAS and Gd2Zr2O7 was seen. This reaction layer inhibited to further penetration of the reaction products inside of the FG8. (C) 2017 Elsevier Ltd. All rights reserved.