| Autor: |
Gleich, Stephan, Fager, Hanna, Bolvardi, Hamid, Achenbach, Jan-Ole, Soler, Rafael, Pradeep, Konda Gokuldoss, Schneider, Jochen M., Dehm, Gerhard, Scheu, Christina |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 2017, Vol. 122 Issue 7, p1-9, 9p |
| Abstrakt: |
In this work, the nanostructure of a Mo2BC hard coating was determined by several transmission electron microscopy methods and correlated with the mechanical properties. The coating was deposited on a Si (100) wafer by bipolar pulsed direct current magnetron sputtering from a Mo2BC compound target in Ar at a substrate temperature of 630 °C. Transmission electron microscopy investigations revealed structural features at various length scales: bundles (30 nm to networks of several micrometers) consisting of columnar grains (∼10 nm in diameter), grain boun∼dary regions with a less ordered atomic arrangement, and defects including disordered clusters (∼1.5 nm in diameter) as well as stacking faults within the grains. The most prominent defect with a volume fraction of ∼0.5% is the disordered clusters, which were investigated in detail by electron energy loss spectroscopy and atom probe tomography. The results provide conclusive evidence that Ar is incorporated into the Mo2BC film as disordered Ar-rich Mo-B-C clusters of approximately 1.5 nm in diameter. Hardness values of 2861 GPa were obtained by nanoindentation tests. The Young’s modulus of the Mo2BC coating exhibits a value of 46269 GPa, which is consistent with ab initio calculations for crystalline and defect free Mo2BC and measurements of combinatorically deposited Mo2BC thin films at a substrate temperature of 900 °C. We conclude that a reduction of the substrate temperature of 270°C has no significant influence on hardness and Young’s modulus of the Mo2BC hard coating, even if its nanostructure exhibits defects. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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