Micropatterned freestanding magnetron sputtered Mg-alloy scaffolds

Haffner, David; Zamponi, Christiane; Miranda, Rodrigo Lima de; Quandt, Eckhard

doi:10.1515/bnm-2015-0007

Cited by 8 publications

(4 citation statements)

References 14 publications

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“…Potassium hydroxide (KOH) (20%) was used to etch selectively the sacrificial AlN layer to achieve the free standing dog-bone shaped samples. Further details on the fabrication process can be found in (Haffner et al, 2015).…”

Section: Experimental Fabricationmentioning

confidence: 99%

Mechanical Properties of Magnetron Sputtered Free Standing Mg-Ag Alloy Films

2019

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Magnesium based alloys gained great interest for medical biodegradable applications. Limitations arise from high corrosion rates and mechanical properties of the Mg based alloys. In recent work it was shown that the corrosion rate of a precipitate free Mg-6Ag thin film can be reduced by a factor of three compared to pure sputtered Mg. As Mg-6Ag combines the very promising corrosion results with a potential therapeutically use of Ag ions, the investigation of their mechanical properties is needed for a full characterization of Mg-Ag alloys as biodegradable material. In this work the Ag content was varied from 2 to 10 wt%. The investigated thin film samples were dog-bone shaped samples with a thickness of 20 µm. The samples were fabricated by a combination of UV lithography, sacrificial layer technique and magnetron sputtering. The mechanical properties were determined using uniaxial tensile test. Compared to pure Mg samples fabricated by the same processing route the yield strength is approximately doubled for Ag containing samples. For films with a Ag concentration up to 8 wt% the elongation at fracture reaches a value of ∼7%. Further increase of the Ag concentration leads to lower elongation at fracture. Thus, especially due to the low corrosion rate, Mg-6Ag shows the optimum of all investigated alloys, with a yield strength of ∼310 MPa and an elongation at fracture of ∼6%.

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Section: Experimental Fabricationmentioning

confidence: 99%

Mechanical Properties of Magnetron Sputtered Free Standing Mg-Ag Alloy Films

2019

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“…Recent studies by Zamponi, de Miranda, and Siekmeyer et al [ 40 , 41 , 42 , 43 ] showed that magnetron sputtering can be used to fabricate in situ structured and freestanding NiTi foils. Schlüter and Haffner et al [ 44 , 45 , 46 , 47 ] demonstrated that this method can be used as well for freestanding, biodegradable Mg-based devices. It was shown that the technique allows the fabrication of scaffold devices with a film thickness up to 250 µm and minimal feature sizes of 5 µm [ 47 ].…”

Section: Introductionmentioning

confidence: 99%

“…Schlüter and Haffner et al [ 44 , 45 , 46 , 47 ] demonstrated that this method can be used as well for freestanding, biodegradable Mg-based devices. It was shown that the technique allows the fabrication of scaffold devices with a film thickness up to 250 µm and minimal feature sizes of 5 µm [ 47 ].…”

Section: Introductionmentioning

confidence: 99%

Magnetron Sputtering as a Fabrication Method for a Biodegradable Fe32Mn Alloy

2017

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Biodegradable metals are a topic of great interest and Fe-based materials are prominent examples. The research task is to find a suitable compromise between mechanical, corrosion, and magnetic properties. For this purpose, investigations regarding alternative fabrication processes are important. In the present study, magnetron sputtering technology in combination with UV-lithography was used in order to fabricate freestanding, microstructured Fe32Mn films. To adjust the microstructure and crystalline phase composition with respect to the requirements, the foils were post-deposition annealed under a reducing atmosphere. The microstructure and crystalline phase composition were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. Furthermore, for mechanical characterization, uniaxial tensile tests were performed. The in vitro corrosion rates were determined by electrochemical polarization measurements in pseudo-physiological solution. Additionally, the magnetic properties were measured via vibrating sample magnetometry. The foils showed a fine-grained structure and a tensile strength of 712 MPa, which is approximately a factor of two higher compared to the sputtered pure Fe reference material. The yield strength was observed to be even higher than values reported in literature for alloys with similar composition. Against expectations, the corrosion rates were found to be lower in comparison to pure Fe. Since the annealed foils exist in the austenitic, and antiferromagnetic γ-phase, an additional advantage of the FeMn foils is the low magnetic saturation polarization of 0.003 T, compared to Fe with 1.978 T. This value is even lower compared to the SS 316L steel acting as a gold standard for implants, and thus enhances the MRI compatibility of the material. The study demonstrates that magnetron sputtering in combination with UV-lithography is a new concept for the fabrication of already in situ geometrically structured FeMn-based foils with promising mechanical and magnetic properties.

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“…The usage of magnetron sputtering in combination of UV lithography for the fabrication of NiTi devices for medical applications was first shown by Zamponi, Siekmeyer, and de Miranda et al [ 16 , 17 , 18 , 19 ]. Furthermore, the method was adapted by Schlüter and Haffner et al for the fabrication of biodegradable Mg-based devices with feature sizes down to 5 μm [ 20 , 21 , 22 , 23 ]. In other work, the technique was used for the fabrication of biodegradable FeMn foils.…”

Section: Introductionmentioning

confidence: 99%

Magnetron-Sputtered, Biodegradable FeMn Foils: The Influence of Manganese Content on Microstructure, Mechanical, Corrosion, and Magnetic Properties

et al. 2018

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FeMn alloys show a great potential for the use as a biodegradable material for medical vascular implants. To optimize the material properties, with respect to the intended application, new fabrication methods also have to be investigated. In this work different Fe–FeMn32 multilayer films were deposited by magnetron sputtering. The deposition was done on a substrate structured by UV lithography. This technique allows the fabrication of in-situ structured foils. In order to investigate the influence of the Mn content on the material properties foils with an overall Mn content of 5, 10, 15, and 17 wt % were fabricated. The freestanding foils were annealed post-deposition, in order to homogenize them and adjust the material properties. The material was characterized in terms of microstructure, corrosion, mechanical, and magnetic properties using X-ray diffraction, electron microscopy, electrochemical polarization, immersion tests, uniaxial tensile tests, and vibrating sample magnetometry. Due to the unique microstructure that can be achieved by the fabrication via magnetron sputtering, the annealed foils showed a high mechanical yield strength (686–926 MPa) and tensile strength (712–1147 MPa). Owing the stabilization of the non-ferromagnetic ε- and γ-phase, it was shown that even Mn concentrations of 15–17 wt % are sufficient to distinctly enhance the magnetic resonance imaging (MRI) compatibility of FeMn alloys.

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Micropatterned freestanding magnetron sputtered Mg-alloy scaffolds

Cited by 8 publications

References 14 publications

Mechanical Properties of Magnetron Sputtered Free Standing Mg-Ag Alloy Films

Mechanical Properties of Magnetron Sputtered Free Standing Mg-Ag Alloy Films

Magnetron Sputtering as a Fabrication Method for a Biodegradable Fe32Mn Alloy

Magnetron-Sputtered, Biodegradable FeMn Foils: The Influence of Manganese Content on Microstructure, Mechanical, Corrosion, and Magnetic Properties

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