Processing and characterization of CYSZ/Al2O3 and CYSZ/Al2O3+YSZ multilayered thermal barrier coatings

Mehmet Mumtaz Dokur; Gultekin Goller

doi:10.1016/j.surfcoat.2014.07.077

Processing and characterization of CYSZ/Al₂O₃ and CYSZ/Al₂O₃+YSZ multilayered thermal barrier coatings

Mehmet Mumtaz Dokur, Gultekin Goller^*

^*Corresponding author for this work

Department of Metallurgical and Materials Engineering

Istanbul Technical University

Research output: Contribution to journal › Article › peer-review

40 Citations (Scopus)

Abstract

CYSZ/Al₂O₃ and CYSZ/Al₂O₃+YSZ multilayer ceramic coatings were produced in 4, 8 and 12 layered with a total thickness of ~400μm by high-velocity oxy-fuel (HVOF) and atmospheric plasma spraying (APS) processes. Microstructure, thermal and mechanical properties were evaluated. The thickness of metallic bonding layer and total thickness of ceramic top layer were measured as 100±10μm and 400±20μm, respectively. Porosity levels of multilayer coatings were observed between 6 and 13%. Thermal conductivity values of the CYSZ/Al₂O₃ and CYSZ/Al₂O₃+YSZ coatings were in the range of 0.99 to 1.50W/mK. The bonding strength of as-sprayed coatings was increased from 5.4 to 10.1MPa for CYSZ/Al₂O₃, and 8.7 to 11.5MPa for CYSZ/Al₂O₃+YSZ coatings with the increasing number of layers. Existence of phase transformation (γ→α) for Al₂O₃ coating was observed after the thermal cycle test. The results indicated that the thermal conductivity and thermal cycle strength of CYSZ/Al₂O₃+YSZ TBCs were higher than CYSZ/Al₂O₃ based thermal barrier coatings.

Original language	English
Pages (from-to)	804-813
Number of pages	10
Journal	Surface and Coatings Technology
Volume	258
DOIs	https://doi.org/10.1016/j.surfcoat.2014.07.077
Publication status	Published - 15 Nov 2014

Bibliographical note

Publisher Copyright:
© 2014 Elsevier B.V.

Funding

This work was supported by the Scientific and Technological Research Council of Turkey , 1002 Short Term Research and Development Funding Program with a project number of 111M430 . The authors thank Prof. Dr. Yilmaz Taptik and Assoc. Prof. Dr. Ozgul Keles for their contributions on thermal spray processes.

Funders	Funder number
Türkiye Bilimsel ve Teknolojik Araştirma Kurumu	111M430

Keywords

AlO
Bonding strength
CYSZ
Thermal conductivity
Thermal cycle
Thermal spray

Access to Document

10.1016/j.surfcoat.2014.07.077

Cite this

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title = "Processing and characterization of CYSZ/Al2O3 and CYSZ/Al2O3+YSZ multilayered thermal barrier coatings",

abstract = "CYSZ/Al2O3 and CYSZ/Al2O3+YSZ multilayer ceramic coatings were produced in 4, 8 and 12 layered with a total thickness of ~400μm by high-velocity oxy-fuel (HVOF) and atmospheric plasma spraying (APS) processes. Microstructure, thermal and mechanical properties were evaluated. The thickness of metallic bonding layer and total thickness of ceramic top layer were measured as 100±10μm and 400±20μm, respectively. Porosity levels of multilayer coatings were observed between 6 and 13%. Thermal conductivity values of the CYSZ/Al2O3 and CYSZ/Al2O3+YSZ coatings were in the range of 0.99 to 1.50W/mK. The bonding strength of as-sprayed coatings was increased from 5.4 to 10.1MPa for CYSZ/Al2O3, and 8.7 to 11.5MPa for CYSZ/Al2O3+YSZ coatings with the increasing number of layers. Existence of phase transformation (γ→α) for Al2O3 coating was observed after the thermal cycle test. The results indicated that the thermal conductivity and thermal cycle strength of CYSZ/Al2O3+YSZ TBCs were higher than CYSZ/Al2O3 based thermal barrier coatings.",

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AB - CYSZ/Al2O3 and CYSZ/Al2O3+YSZ multilayer ceramic coatings were produced in 4, 8 and 12 layered with a total thickness of ~400μm by high-velocity oxy-fuel (HVOF) and atmospheric plasma spraying (APS) processes. Microstructure, thermal and mechanical properties were evaluated. The thickness of metallic bonding layer and total thickness of ceramic top layer were measured as 100±10μm and 400±20μm, respectively. Porosity levels of multilayer coatings were observed between 6 and 13%. Thermal conductivity values of the CYSZ/Al2O3 and CYSZ/Al2O3+YSZ coatings were in the range of 0.99 to 1.50W/mK. The bonding strength of as-sprayed coatings was increased from 5.4 to 10.1MPa for CYSZ/Al2O3, and 8.7 to 11.5MPa for CYSZ/Al2O3+YSZ coatings with the increasing number of layers. Existence of phase transformation (γ→α) for Al2O3 coating was observed after the thermal cycle test. The results indicated that the thermal conductivity and thermal cycle strength of CYSZ/Al2O3+YSZ TBCs were higher than CYSZ/Al2O3 based thermal barrier coatings.

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