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Micromechanical interaction of nitinol with carbon-based coatings
DOI:10.1016/j.diamond.2026.113732.png)
Abstract
En 中文
The micromechanical properties, adhesion, and surface roughness of silicon- and oxygen-containing hydrocarbon coatings (a-C:H:SiOx) and their titanium-doped counterpart (a-C:H:SiOx:Ti), as well as a non‑hydrogenated DLC coating, deposited on a Ni49.9Ti50.1 (NiTi) alloy used for vascular stents, were investigated. Nanoindentation and microscratch tests revealed that the a-C:H:SiOx and a-C:H:SiOx:Ti coatings exhibit critical loads Lc1 of 18–23 N and ≥23 N, respectively, which significantly exceed those of the DLC coating (4–8 N). The hardness of the a-C:H:SiOx and a-C:H:SiOx:Ti coatings is 14–15 GPa, whereas the DLC coating has a hardness of approximately 41 GPa. Transmission electron microscopy and X-ray photoelectron spectroscopy showed that all coatings are amorphous; titanium doping (0.6 at.%) does not lead to the formation of TiC chemical bonds. The a-C:H:SiOx and a-C:H:SiOx:Ti coatings retain a low average surface roughness (Sa ≈ 0.21–0.28 μm) with pronounced valleys (Sv ≈ 0.77–0.99 μm), while the DLC coating increases the roughness to Sa ≈ 0.30 μm. The combination of high adhesion, moderate hardness, and favorable surface topography makes a-C:H:SiOx-type coatings, particularly the Ti-doped variant, a promising approach for enhancing the functionality and durability of NiTi-based vascular stents.
Keywords:
a-C:H:SiOx
a-C:H:SiOx:Ti
NiTi alloy
nanoindentation
microscratch
Journal
IF:
5.1
Papers:
2.1K
Citations:
2.4W


