1. Evaluation of Cr-based thin film metallic glass as a potential replacement of PVD chromium coating on plastic mold surface.
- Author
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Yiu, Pakman, Bönninghoff, Niklas, and Chu, Jinn P.
- Subjects
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METALLIC thin films , *METALLIC glasses , *PHYSICAL vapor deposition , *SURFACE energy , *CHROMIUM , *CONTACT angle - Abstract
In this article, a CrCoNbB thin film metallic glass (TFMG) is fabricated by DC power magnetron sputtering. Its microstructure, surface properties, mechanical properties and thermal stability are characterized. Results are compared with sputter-deposited chromium (Cr) coating which is an industrial popular choice of hard coating by physical vapor deposition (PVD). We obtained a fully amorphous Cr 48 Co 31 Nb 7 B 14 TFMG with glass transition (T g) and crystallization (T x) temperatures at 530 °C and 615 °C, respectively. Nanoindentation revealed that Cr 48 Co 31 Nb 7 B 14 TFMG has significantly lower surface roughness and higher hardness than Cr. Also, in nano-scratch test with normal load applied between 0.5 mN ~ 9 mN, Cr 48 Co 31 Nb 7 B 14 TFMG has a lower coefficient of friction (CoF) than Cr. Annealing the TFMG above T g at 550 °C for 60 min showed no sign of crystallization, implying excellent thermal stability. Contact angle analysis also revealed that the TFMG has very low surface free energy (SFE), specifically a low polar component. We also discovered that spreading of molten low-density polyethylene (LDPE) on Cr 48 Co 31 Nb 7 B 14 TFMG is weaker than on Cr film as a consequence of its low SFE. In summary, Cr 48 Co 31 Nb 7 B 14 TFMG has advantages such as high hardness and thermal stability, low roughness, friction and surface energy compared to PVD Cr coating. Low adhesion to molten LDPE also suggests its potential in applications such as injection mold coating where lower friction and higher wear resistance is preferred. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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