Microstructure and Tribological Properties of Plasma-Sprayed Al0.2Co1.5CrFeNi1.5Ti-Ag Composite Coating from 25 to 750 °C
Abstract
High-entropy alloys (HEAs) have been deliberated as potential matrix material for self-lubricating composites due to their excellent mechanical properties. In this study, the Al0.2Co1.5CrFeNi1.5Ti HEA powders with a face-centered cubic structure were prepared by mechanical alloying. Then, the alloyed HEA powders were sintered at 700 °C to achieve sprayed powder with suitable particle size. Next, the Al0.2Co1.5CrFeNi1.5Ti HEA-based composite coating was plasma sprayed on carbon steel by combining Ag. Dry friction experiment was applied in order to investigate the tribological properties of HEA - Ag composite coating at temperatures ranging from 25 to 750 °C. The composite coating that was sprayed with HEA - Ag exhibited a low friction coefficient (0.253) and a relatively low wear rate (8.9 × 10-6 mm3/Nm) at 750 °C. Furthermore, the HEA + Ag coating obtained an increased hardness and superior tribological properties after high temperature annealing. The dense, continuous oxide layer that was formed tightly covered the coating surface and combined with the lubrication of Ag clusters to protect the underlying materials from wear loss at high temperatures.
- Publication:
-
Journal of Materials Engineering and Performance
- Pub Date:
- March 2020
- DOI:
- 10.1007/s11665-020-04700-5
- Bibcode:
- 2020JMEP...29.1640L
- Keywords:
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- high-entropy alloy;
- lubricating composite coating;
- mechanical alloying;
- plasma spraying