Crack propagation and effect of mixed oxides on TGO growth in thick La-Gd-YSZ thermal barrier coating
Thick thermal barrier coatings (TBCs) are the main choice in the aviation industry due to their ability to handle elevated temperature exposure in turbines. However, the efficacy of thick TBCs has not been adequate. This study presents a highly durable, thick top-coat (TC) of Lanthanum-gadolinium-yt...
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my.uniten.dspace-249122023-05-29T15:28:43Z Crack propagation and effect of mixed oxides on TGO growth in thick La-Gd-YSZ thermal barrier coating Mahalingam S. Yunus S.M. Manap A. Afandi N.M. Zainuddin R.A. Kadir N.F. 55434075500 56902397100 57200642155 57189231851 57211976085 24481091600 Thick thermal barrier coatings (TBCs) are the main choice in the aviation industry due to their ability to handle elevated temperature exposure in turbines. However, the efficacy of thick TBCs has not been adequate. This study presents a highly durable, thick top-coat (TC) of Lanthanum-gadolinium-yttria stabilized zirconia (La-Gd-YSZ) on high-velocity oxygen fuel (HVOF)-bond coat (HVOF-BC). Crack propagation was quantitatively assessed using a three-dimensional (3D) measuring laser microscope due to higher reliability in calculating the actual crack length of TBC. The findings revealed the HVOF-BC is highly durable with intact structural composition, while the conventional TBC of atmospheric plasma spraying (APS) bond coat (APS-BC) of the same composition and thickness with identical TC was detached at a crack-susceptible zone. The significant enhancement in HVOF-BC is due to the low mixed-oxides growth rate in thermally grown oxide (TGO) with a uniform and dense protective layer of stable Al2O3 which reduces crack propagation. Meanwhile, the failure in APS-BC can be attributed to the high TGO growth rate and thickness with segmented and unstable Al2O3. Furthermore, detrimental mixed oxides such as spinel Ni(Cr,Al)2O4 and NiO lead to disastrous horizontal and compressive cracks. To that end, we study the effect of TGO growth and crack propagation on HVOF-BC TBCs using APS-BC TBCs as a reference. � 2019 by the authors. Final 2023-05-29T07:28:43Z 2023-05-29T07:28:43Z 2019 Article 10.3390/coatings9110719 2-s2.0-85075553144 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075553144&doi=10.3390%2fcoatings9110719&partnerID=40&md5=8574d30c84583ebcc2c3394fc58406e4 https://irepository.uniten.edu.my/handle/123456789/24912 9 11 719 All Open Access, Gold MDPI AG Scopus |
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Thick thermal barrier coatings (TBCs) are the main choice in the aviation industry due to their ability to handle elevated temperature exposure in turbines. However, the efficacy of thick TBCs has not been adequate. This study presents a highly durable, thick top-coat (TC) of Lanthanum-gadolinium-yttria stabilized zirconia (La-Gd-YSZ) on high-velocity oxygen fuel (HVOF)-bond coat (HVOF-BC). Crack propagation was quantitatively assessed using a three-dimensional (3D) measuring laser microscope due to higher reliability in calculating the actual crack length of TBC. The findings revealed the HVOF-BC is highly durable with intact structural composition, while the conventional TBC of atmospheric plasma spraying (APS) bond coat (APS-BC) of the same composition and thickness with identical TC was detached at a crack-susceptible zone. The significant enhancement in HVOF-BC is due to the low mixed-oxides growth rate in thermally grown oxide (TGO) with a uniform and dense protective layer of stable Al2O3 which reduces crack propagation. Meanwhile, the failure in APS-BC can be attributed to the high TGO growth rate and thickness with segmented and unstable Al2O3. Furthermore, detrimental mixed oxides such as spinel Ni(Cr,Al)2O4 and NiO lead to disastrous horizontal and compressive cracks. To that end, we study the effect of TGO growth and crack propagation on HVOF-BC TBCs using APS-BC TBCs as a reference. � 2019 by the authors. |
| author2 |
55434075500 |
| author_facet |
55434075500 Mahalingam S. Yunus S.M. Manap A. Afandi N.M. Zainuddin R.A. Kadir N.F. |
| format |
Article |
| author |
Mahalingam S. Yunus S.M. Manap A. Afandi N.M. Zainuddin R.A. Kadir N.F. |
| spellingShingle |
Mahalingam S. Yunus S.M. Manap A. Afandi N.M. Zainuddin R.A. Kadir N.F. Crack propagation and effect of mixed oxides on TGO growth in thick La-Gd-YSZ thermal barrier coating |
| author_sort |
Mahalingam S. |
| title |
Crack propagation and effect of mixed oxides on TGO growth in thick La-Gd-YSZ thermal barrier coating |
| title_short |
Crack propagation and effect of mixed oxides on TGO growth in thick La-Gd-YSZ thermal barrier coating |
| title_full |
Crack propagation and effect of mixed oxides on TGO growth in thick La-Gd-YSZ thermal barrier coating |
| title_fullStr |
Crack propagation and effect of mixed oxides on TGO growth in thick La-Gd-YSZ thermal barrier coating |
| title_full_unstemmed |
Crack propagation and effect of mixed oxides on TGO growth in thick La-Gd-YSZ thermal barrier coating |
| title_sort |
crack propagation and effect of mixed oxides on tgo growth in thick la-gd-ysz thermal barrier coating |
| publisher |
MDPI AG |
| publishDate |
2023 |
| _version_ |
1806424419254403072 |
| score |
13.211869 |