Improving the radiopacity of Fe-Mn biodegradable metals by magnetron-sputtered W-Fe-Mn-C coatings: Application for thinner stents.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35087963.
- Also identified by DOI 10.1016/j.bioactmat.2021.10.022 and PMC identifier 8777240.
- Licence recorded as CC BY-NC-ND.
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Abstract
In this exploratory work, micrometric radiopaque W-Fe-Mn-C coatings were produced by magnetron sputtering plasma deposition, for the first time, with the aim to make very thin Fe-Mn stents trackable by fluoroscopy. The power of Fe-13Mn-1.2C target was kept constant at 400 W while that of W target varied from 100 to 400 W producing three different coatings referred to as <i>P</i>100, <i>P</i>200, <i>P</i>400. The effect of the increased W power on coatings thickness, roughness, structure, corrosion behavior and radiopacity was investigated. The coatings showed a power-dependent thickness and W concentration, different roughness values while a similar and uniform columnar structure. An amorphous phase was detected for both <i>P</i>100 and <i>P</i>200 coatings while γ-Fe, bcc-W and W<sub>3</sub>C phases found for <i>P</i>400. Moreover, <i>P</i>200 and <i>P</i>400 showed a significantly higher corrosion rate (CR) compared to <i>P</i>100. The presence of W, W<sub>3</sub>C as well as the Fe amount variation determined two different micro-galvanic corrosion mechanisms significantly changing the CR of coatings, 0.26 ± 0.02, 59.68 ± 1.21 and 59.06 ± 1.16 μm/year for <i>P</i>100, <i>P</i>200 and <i>P</i>400, respectively. Sample <i>P</i>200 with its most uniform morphology, lowest roughness (RMS = 3.9 ± 0.4 nm) and good radiopacity (∼6%) appeared the most suitable radiopaque biodegradable coating investigated in this study.