Friction Properties of Alumina–Silicon Carbide–Silver–Graphene Nanoplatelet Self-Lubricating Composite Prepared by SPS Technique
Al<sub>2</sub>O<sub>3</sub> with SiC, silver, and graphene nanoplatelets (GNPs) powder mixture was produced by ball milling using ethanol as dispersion media. The GNP-reinforced Al<sub>2</sub>O<sub>3</sub>-SiC-Ag ceramic–metal composites were densified...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Lubricants |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-4442/13/1/3 |
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| Summary: | Al<sub>2</sub>O<sub>3</sub> with SiC, silver, and graphene nanoplatelets (GNPs) powder mixture was produced by ball milling using ethanol as dispersion media. The GNP-reinforced Al<sub>2</sub>O<sub>3</sub>-SiC-Ag ceramic–metal composites were densified by spark plasma sintering technology (SPS). A homogeneous dispersion of GNPs in Al<sub>2</sub>O<sub>3</sub>-SiC-Ag was observed from the sintered samples, and the GNPs were embedded between the grains, which resulted in increasing the contact area. The trans-granular mechanism of crack propagation becomes increasingly dominant by adding GNPs. The hardness reaches 27 GPa, as tested by the Vickers microhardness method, which reflects an increase of 11% compared to Ag-GNPs-free Al<sub>2</sub>O<sub>3</sub>-SiC. On the other hand, by adding Ag-GNP content, the improvement in density is limited. Wear mechanisms, as determined through ball-on-flat testing, including adhesion, abrasion, and microcracks, are observed and discussed. The composite demonstrated remarkable self-lubricating properties, exhibiting a lower coefficient of friction (COF) and wear rate in an air environment compared to monolithic Al₂O₃-SiC. This improvement is attributed to the formation of a self-lubricating film, enabled by the uniform distribution of Ag and GNPs within the Al₂O₃-SiC matrix. The findings of this study propose a novel material design approach for developing self-lubricating ceramic composites with hybrid solid lubricants. |
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| ISSN: | 2075-4442 |