Next Article in Journal
Antifungal Starch–Gellan Edible Coatings with Thyme Essential Oil for the Postharvest Preservation of Apple and Persimmon
Next Article in Special Issue
Crack Healing in Mullite-Based EBC during Thermal Shock Cycle
Previous Article in Journal
The Effect of Transglutaminase to Improve the Quality of Either Traditional or Pectin-Coated Falafel (Fried Middle Eastern Food)
Open AccessArticle

Flow Kinetics of Molten Silicates through Thermal Barrier Coating: A Numerical Study

1
Experimental and Numerical Methods, Institute of Materials Research, German Aerospace Center (DLR), Linder Höhe, 51147 Cologne, Germany
2
High Temperature and Functional Coatings, Institute of Materials Research, German Aerospace Center (DLR), Linder Höhe, 51147 Cologne, Germany
*
Author to whom correspondence should be addressed.
Coatings 2019, 9(5), 332; https://doi.org/10.3390/coatings9050332
Received: 16 April 2019 / Revised: 20 May 2019 / Accepted: 21 May 2019 / Published: 23 May 2019
(This article belongs to the Special Issue Environmental Barrier Coatings)
Infiltration of molten calcium–magnesium–alumina–silicates (CMAS) through thermal barrier coatings (TBCs) causes structural degradation of TBC layers. The infiltration kinetics can be altered by careful tailoring of the electron beam physical vapor deposition (EB-PVD) microstructure such as feather arm lengths and inter-columnar gaps, etc. Morphology of the feathery columns and their inherent porosities directly influences the infiltration kinetics of molten CMAS. To understand the influence of columnar morphology on the kinetics of the CAMS flow, a finite element based parametric model was developed for describing a variety of EB-PVD top coat microstructures. A detailed numerical study was performed considering fluid-solid interactions (FSI) between the CMAS and TBC top coat (TC). The CMAS flow characteristics through these microstructures were assessed quantitatively and qualitatively. Finally, correlations between the morphological parameters and CMAS flow kinetics were established. It was shown that the rate of longitudinal and lateral infiltration could be minimized by reducing the gap between columns and increasing the length of the feather arms. The results also show that the microstructures with long feather arms having a lower lateral inclination decrease the CMAS infiltration rate, therefore, reduce the CMAS infiltration depth. The analyses allow the identification of key morphological features that are important for mitigating the CMAS infiltration. View Full-Text
Keywords: TBCs; CMAS; infiltration; microstructure; modeling; finite element TBCs; CMAS; infiltration; microstructure; modeling; finite element
Show Figures

Figure 1

MDPI and ACS Style

Kabir, M.R.; Sirigiri, A.K.; Naraparaju, R.; Schulz, U. Flow Kinetics of Molten Silicates through Thermal Barrier Coating: A Numerical Study. Coatings 2019, 9, 332.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop