Change search
ReferencesLink to record
Permanent link

Direct link
High-temperature degradation of plasma sprayed thermal barrier coating systems
Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, The Institute of Technology.
2011 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Thermal barrier coating systems (TBCs) are used in gas turbines to prevent high-temperature degradation of metallic materials in the combustor and turbine. One of the main concerns regarding TBCs is poor reliability, and accurate life prediction models are necessary in order to fully utilise the beneficial effects of TBCs. This research project aims at developing deeper understanding of the degradation and failure mechanisms acting on TBCs during high temperature exposure, and to use this knowledge to improve life assessments of TBCs. The present work includes a study on the influence of coating interface morphology on the fatigue life of TBCs and a study on the influence of some different heat treatments on the adhesive properties of TBCs.

The influence of coating interface morphology on fatigue life has been studied both experimentally and by modelling. Large interface roughness has been found experimentally to increase fatigue life of TBCs. The modelling work do, to some extent, capture this behaviour. It is evident, from the study, that interface morphology has a large impact on fatigue life of TBCs.

Three thermal testing methods, that degrade TBCs, have been investigated: isothermal oxidation, furnace cycling and burner rig test. The degraded TBCs have been evaluated by adhesion tests and microscopy. The adhesion of TBCs has been found to depend on heat treatment type and length. Cyclic heat treatments, (furnace cycling and burner rig test), lower the adhesion of TBCs while isothermal oxidation increases adhesion. The fracture surfaces from the adhesion tests reveal that failure strongly depends on the pre-existing defects in the TBC.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press , 2011. , 49 p.
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1484
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:liu:diva-67885Local ID: LIU–TEK–LIC–2011:23ISBN: 978-91-7393-165-6OAI: oai:DiVA.org:liu-67885DiVA: diva2:414013
Presentation
2011-05-27, ACAS, Plan 2, A-huset, Campus Valla, Linköpings universitet, Linköping, 13:15 (Swedish)
Opponent
Supervisors
Available from: 2011-05-02 Created: 2011-05-02 Last updated: 2011-09-27Bibliographically approved
List of papers
1. Fracture Mechanical Modelling of a Plasma Sprayed TBC System
Open this publication in new window or tab >>Fracture Mechanical Modelling of a Plasma Sprayed TBC System
2009 (English)In: Advanced Ceramic Coatings and Interfaces IV / [ed] Dongming Zhu and Hua-Tay Lin, Westerville, OH, United States: American Ceramic Society Inc. , 2009, Vol. 30, no 3, 113-124 p.Conference paper (Refereed)
Abstract [en]

A thermal barrier coating (TBC) system subjected to thermal cycling will develop a microcrack partem near the interface between the metallic bond coat and the ceramic top coat. These small cracks link up and form internal TBC delaminations during repeated heating / cooling. After a longer time period, the internal delamination cracks will form a larger spallation damage, where the TBC is detached from the underlying material. Since cracks are initiated in multiple sites of the thermal barrier coating, the damage is initially considered to be governed by local stress conditions. The purpose of the present work is to compare experimental data with predictions of a physically based fatigue life model. The present study has been performed on plasma-sprayed TBCs where the interface geometry has been varied. In the present work, calculation of fatigue life is done for a number of cases under thermal fatigue loading. Different interface geometries are compared in order to understand the influence of variations in the TC/BC interface roughness on oxidation behaviour and thermal fatigue life. Thermal fatigue tests indicate that an increased surface roughness is beneficial from a fatigue life point of view.

Place, publisher, year, edition, pages
Westerville, OH, United States: American Ceramic Society Inc., 2009
Series
, Ceramic Engineering and Science Proceedings, ISSN 0196-6219 ; 3
Keyword
Fracture mechanical modelling, thermal barrier coating, plasma spraying, thermal cycling, metallic bond coat
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-57007 (URN)10.1002/9780470584293.ch12 (DOI)000281124900012 ()978-0-470-45753-5 (ISBN)
Conference
33rd International Conference on Advanced Ceramics and Composites, Daytona Beach, FL, USA, January 18-23, 2009
Available from: 2010-06-14 Created: 2010-06-09 Last updated: 2016-05-17Bibliographically approved
2. Influence of isothermal and cyclic heat treatments on the adhesion of plasma sprayed thermal barrier coatings
Open this publication in new window or tab >>Influence of isothermal and cyclic heat treatments on the adhesion of plasma sprayed thermal barrier coatings
Show others...
2011 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 205, no 23-24, 5422-5429 p.Article in journal (Refereed) Published
Abstract [en]

The adhesion of thermal barrier coatings (TBC) has been studied using the standard method described in ASTM C633, which makes use of a tensile test machine to measure the adhesion. The studied specimens consist of air plasma sprayed (APS) TBC deposited on disc-shaped substrate coupons of Ni-base alloy Hastelloy X. The bond coat (BC) is of a NiCoCrAlY type and the top coat (TC) consists of yttria–stabilised–zirconia. Before the adhesion test, the specimens were subjected to three different heat treatments: 1) isothermal oxidation at 1100 °C up to 290 h, 2) thermal cycling fatigue (TCF) at 1100 °C up to 300 cycles and 3) thermal shock at ~ 1140 °C BC/TC interface temperature up to 1150 cycles. The adhesion of the specimens is reported and accompanied by a microstructural study of the BC and the thermally grown oxides (TGO), as well as a discussion on the influence of BC/TC interfacial damage on adhesion properties of TBC. The adhesion was found to vary with heat treatment, as well as with heat treatment length.

Place, publisher, year, edition, pages
Elsevier, 2011
Keyword
Thermal barrier coating, TBC, adhesion, thermal cycling fatigue, thermal shock, burner rig test
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-67882 (URN)10.1016/j.surfcoat.2011.06.007 (DOI)000294103700025 ()
Available from: 2011-05-02 Created: 2011-05-02 Last updated: 2013-08-27Bibliographically approved
3. Fractographic and microstructural study of isothermally and cyclically heat treated thermal barrier coatings
Open this publication in new window or tab >>Fractographic and microstructural study of isothermally and cyclically heat treated thermal barrier coatings
Show others...
2014 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 243, 82-90 p.Article in journal (Refereed) Published
Abstract [en]

The fracture surfaces from adhesion tested thermal barrier coatings (TBC) have been studied by scanning electron microscopy. The adhesion test have been made using the standard method described in ASTM 633, which makes use of a tensile test machine to measure the adhesion. The studied specimens consist of air plasma sprayed (APS) TBC deposited on disc-shaped substrates of Hastelloy X. The bond coat (BC) is of NiCoCrAlY type and the top coat (TC) consists of yttria–stabilised–zirconia. Before the adhesion test, the specimens were subjected to three different heat treatments: 1) isothermal oxidation 2) thermal cycling fatigue (TCF) and 3) burner rig test (BRT). The fracture surfaces of the adhesion tested specimens where characterised. A difference in fracture mechanism were found for the different heat treatments. Isothermal oxidation gave fracture mainly in the top coat while the two cyclic heat treatments gave increasing amount of BC/TC interface fracture with number of cycles. Some differences could also be seen between the specimens subjected to burner rig test and furnace cycling.

Keyword
Thermal barrier coating, TBC, fractography, adhesion, thermal cycling, burner rig
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-67883 (URN)10.1016/j.surfcoat.2012.02.040 (DOI)000335542100014 ()
Note

On the day of the defence date of the Thesis the status of this article was Manuscript.

Available from: 2011-05-02 Created: 2011-05-02 Last updated: 2014-06-05Bibliographically approved
4. Fractographic Study of Adhesion Tested Thermal Barrier Coatings Subjected to Isothermal and Cyclic Heat Treatments
Open this publication in new window or tab >>Fractographic Study of Adhesion Tested Thermal Barrier Coatings Subjected to Isothermal and Cyclic Heat Treatments
Show others...
2011 (English)In: Procedia Engineering, ISSN 1877-7058, Vol. 10, 195-200 p.Article in journal (Refereed) Published
Abstract [en]

Thermal barrier coatings (TBC) are used in gas turbines to protect metallic components from high temperature. In the present study adhesion tests have been conducted on APS TBC coated specimens subjected to different heat treatments. Isothermal and cyclic heat treatments have been conducted at temperatures around 1100 °C and the adhesion have been tested using the method described in ASTM C633. The fracture surfaces resulting from the adhesion test have been investigated and the fracture behavior has been characterized. A difference in fracture mechanism between the three heat treatments has been found. The two cyclic heat treatments give fracture in the top coat/bond coat interface while isothermal heat treatment gives fracture in the top coat.

Place, publisher, year, edition, pages
Elsevier: , 2011
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-70541 (URN)10.1016/j.proeng.2011.04.035 (DOI)
Available from: 2011-09-12 Created: 2011-09-12 Last updated: 2014-09-23

Open Access in DiVA

High-temperature degradation of plasma sprayed thermal barrier coating systems(3405 kB)2306 downloads
File information
File name FULLTEXT01.pdfFile size 3405 kBChecksum SHA-512
7c682a323a76d8ba4f8229efa799730b736c21491e9019cbb8c57057ec0d8cdc58fa51999d617352d73d9b3d75775b8ff800f96463b0c4e694ea2c6ea286e2b6
Type fulltextMimetype application/pdf
cover(3601 kB)94 downloads
File information
File name COVER01.pdfFile size 3601 kBChecksum SHA-512
eb6336a649f21d25017792c5a93a3bf70ce10e7aa3c22d2e9d98753faa49c4b3723d9de2c717abc8db0a0ada5b8231292865b0f221bb7e68dd3bd5ed88724ee6
Type coverMimetype application/pdf

Search in DiVA

By author/editor
Eriksson, Robert
By organisation
Engineering MaterialsThe Institute of Technology
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 2309 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 599 hits
ReferencesLink to record
Permanent link

Direct link