Microstructural evolution of Bi-layered NiCrAlY/CeO2 - Graphene Nanoplatelet coatings by air plasma spray and spark plasma sintering
This research outlines the fabrication of NiCrAlY/CeO2 - Graphene Nanoplatelets (GNP) composites via powder metallurgy techniques, including the deposition on stainless steel 316 by Air Plasma Spraying (APS) and further enhancement through Spark Plasma Sintering (SPS). The process commenced with bal...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-03-01
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| Series: | Heliyon |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2405844025013325 |
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| Summary: | This research outlines the fabrication of NiCrAlY/CeO2 - Graphene Nanoplatelets (GNP) composites via powder metallurgy techniques, including the deposition on stainless steel 316 by Air Plasma Spraying (APS) and further enhancement through Spark Plasma Sintering (SPS). The process commenced with ball-milling, followed by the agglomeration of nanostructured powders through spray drying, which was then validated for APS use based on morphology and size distribution assessments. Field Emission Scanning Electron Microscopy (FE-SEM) and Scanning Electron Microscopy (SEM) examination of the as-APS coating surfaces disclosed a range of defects, including splashed particles and areas that were not fully melted. Additionally, SEM imaging highlighted interlamellar cracks and open porosities, raising significant quality concerns. In contrast, the microstructure of the SPS-treated coatings demonstrated substantial improvements, such as the eradication of interlamellar cracks, enhanced microstructural integrity, and a more unified structure. The coatings demonstrated remarkable properties, including a 76 % improvement in microhardness and a significant reduction in porosity for the SPS-treated sample at 900 °C and 30 MPa. XRD analysis confirmed that all samples retained the crystallographic patterns of the original feedstock, illustrating no phase formation or metallurgical transformation at the boundaries of the materials during processing. Furthermore, the microstructural analysis revealed a homogeneous structure with uniform elemental distribution across the layers, ensuring robust interfacial bonding. |
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| ISSN: | 2405-8440 |