Change search
ReferencesLink to record
Permanent link

Direct link
Termisk cyklisk utmattning studie av Gd2Zr2O7 / YSZ flerskikts termiska barriärbeläggningar
University West, Department of Engineering Science, Division of Manufacturing Processes.
2015 (Swedish)Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesisAlternative title
Thermal cyclic fatigue study of Gd2Zr2O7/ YSZ multi-layered thermal barrier coatings (English)
Abstract [en]

From many years YSZ is used as the top coat material for TBC's, as it has good phase stability up to 1200°C, higher fracture toughness, lower thermal conductivity, erosion resistance & higher coefficient of thermal expansion. But, it has a drawbacks at high temperature such as sintering and transformation of phases. For this reason new ceramic materials with pyrochlores crystal structure such as Gd2Zr2O7 are being considered as it has high melting points, phase stability, lower thermal conductivity and CMAS resistance. But it has low fracture toughness when compared to YSZ. In order to take advantage of low thermal conductivity and high thermal stability of gadolinium zirconate and avoiding the drawbacks of low coefficient of thermal expansion and low toughness using YSZ, a double/multi-layer coatings approach is being used. Therefore, multi-layer TBCs are sprayed and compared with single layer coating in this work. These coatings are processed by suspension plasma spraying. For single layer coating YSZ is used, for double layer coating YSZ as the intermediate coating and Gd2Zr2O7 as the top coat is used. Additionally, a triple layer coating system comprising YSZ, Gd2Zr2O7 and dense Gd2Zr2O7 as top coat is also sprayed. The as sprayed coatings are characterized for microstructure analysis using optical microscope and scanning electron microscope (SEM), elemental analysis of TGO using Energy-Dispersive Spectrometer (EDS). XRD analysis was done to identify various phases in the coating. Porosity analysis using Archimedes principle was carried out. Thermal cyclic fatigue (TCF) test of the sprayed coatings was carried out at 1100°C. Failure analysis of the TCF specimens was carried out using SEM/EDS. TCF results showed that the triple layer coatings (dense Gd2Zr2O7/Gd2Zr2O7/YSZ) had higher thermal cyclic fatigue life and lower TGO thickness when compared to single layer (YSZ) and double layer (Gd2Zr2O7/YSZ) TBCs.

Place, publisher, year, edition, pages
2015. , 20 p.
Keyword [en]
Thermal barrier coatings, suspension plasma spraying, thermal cyclic fatigue life, yttria stabilized zirconate (YSZ), gadolinium zirconate (GZ)
National Category
Mechanical Engineering
URN: urn:nbn:se:hv:diva-8266Local ID: EXP800OAI: diva2:857309
Subject / course
Mechanical engineering
Educational program
Available from: 2015-09-30 Created: 2015-09-28 Last updated: 2015-10-23Bibliographically approved

Open Access in DiVA

fulltext(1059 kB)165 downloads
File information
File name FULLTEXT01.pdfFile size 1059 kBChecksum SHA-512
Type fulltextMimetype application/pdf

By organisation
Division of Manufacturing Processes
Mechanical Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 165 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: 123 hits
ReferencesLink to record
Permanent link

Direct link