| 1. |
- Govindararajan, S., et al.
(författare)
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Understanding the Formation of Vertical Cracks in Solution Precursor Plasma Sprayed Yttria-Stabilized-Zirconia Coatings
- 2014
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Ingår i: Journal of The American Ceramic Society. - 0002-7820 .- 1551-2916. ; 97, s. 3396-3406
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Tidskriftsartikel (refereegranskat)abstract
- Yttria-stabilized zirconia (YSZ) deposition by the solution precursor plasma spraying (SPPS) route has been of interest for potential thermal barrier coating (TBC) applications. It has been surmised that realization of unique microstructural features like vertical cracks, nanosized pores and fine splats in the TBCs can significantly enhance coating durability and performance. However, satisfactory control over the YSZ coating microstructure has been elusive in the absence of an adequate understanding of the mechanism responsible for coating deposition in SPPS. This study demonstrates the ability to tailor microstructure of deposited YSZ coatings over a wide range, from nano-porous coatings to a vertically cracked microstructure. Varying of precursor flow rate has been shown to dictate the pyrolysis events occurring in situ and, adopting this approach, YSZ coatings with widely varying microstructural features have been developed. The coatings have been characterized in detail and the observations correlated with in-flight particle generation and splat formation. These studies also provide useful insights into the possible origin of vertical cracks in the coating for which a mechanism is proposed.
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| 2. |
- Joshi, S. V., et al.
(författare)
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Hybrid Plasma-Sprayed Thermal Barrier Coatings Using Powder and Solution Precursor Feedstock
- 2014
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Ingår i: Journal of thermal spray technology (Print). - 1059-9630 .- 1544-1016. ; 23:4, s. 616-624
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Tidskriftsartikel (refereegranskat)abstract
- A novel approach of hybridizing the conventional atmospheric plasma spraying (APS) technique with the solution precursor plasma spray (SPPS) route to achieve thermal barrier coatings (TBCs) with tailored configurations is presented. Such a hybrid process can be conveniently adopted for forming composite, multi-layered and graded coatings employing simultaneous and/or sequential feeding of solution precursor as well as powder feedstock, yielding distinct TBC microstructures that bear promise to further extend coating durability. TBC specimens generated using conventional APS technique, the SPPS method and through APS-SPPS hybrid processing have been comprehensively characterized for microstructure, phase constitution, hardness and thermal cycling life, and the results were compared to demonstrate the advantages that can ensue from hybrid processing.
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