Formation of alpha and beta tantalum at the variation of magnetron sputtering conditions

Biocompatible composites obtained using the magnetron sputtering for the production of minimally invasive implantation medical devices (stents) were investigated. Nano-and microdimensional surface layers of Ta, Ti, Ag, and Cu on flat and wire NiTi, Cu, Ti, and SiO 2 substrates were created. The phase composition, surface morphology, and the layer-by-layer composition were investigated on an X-ray diffractometer, SEM, and Auger spectrometer. It was shown that the thickness and the structure of surface layers were affected by the sputtering distance, time, power, and the bias voltage at the substrate. The presence of the transition layer that contains both substrate and target elements and provides high adhesion of the surface layer to the substrate has been demonstrated. The material was tested for corrosion resistance under static conditions by dipping into solutions with various acidities (pH from 1.68 to 9.18) for 2 years, static mechanical properties, and biocompatibility in vitro and in vivo. A slight corrosive dissolution was observed only in a medium with a pH of 1.56. Dissolution in the other media is absent. An increase in strength and plasticity in comparison with substrate was attained depending on the nature of the sputtered substance and substrate. Toxicity of samples has not been revealed.

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“…Chapter is partially based on the results of earlier published works [35][36][37], and authors have the permission to re-use it.…”

Section: Acknowledgementsmentioning

confidence: 99%

Using of Magnetron Sputtering for Biocompatible Composites Creating

Nasakina¹,

Sevostyanov²,

Баикин³

et al. 2019

Advances in Composite Materials Development

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“…Its structure has been identified as P 4̅2 1 m (113) and results in a 3% lower density (16.3 g cm –3 ) than α-Ta (16.8 g cm –3 ). − We note that the very similar space group of P 4 2 / mnm has also been linked to β-Ta . In sputtered thin films, the occurrence of α/β Ta has been linked to the deposition pressure, substrates temperature − and substrate or seed/adhesion layer material on which the Ta layer is grown. − Although some reports in the literature provide contradictory conclusions, the general consensus seems to be that deposition on amorphous silicon/quartz at low substrate temperatures typically results in β-Ta, while deposition on Mo, Ti, or Cr seed layers at high substrate temperatures results in the formation of α-Ta. − While many studies have been devoted to the structure and occurrence of β-Ta, to the best of our knowledge, the properties of (thin film) β-Ta under hydrogen exposure are still unknown. Detailed knowledge of these properties, as well as how the optical transmission/reflection change with exposure to hydrogen, is key when considering the use of β-Ta as a sensing material in a hydrogen sensor.…”

Section: Introductionmentioning

confidence: 99%

Structural and Optical Properties of Thin Film β-Ta upon Exposure to Hydrogen to Asses Its Applicability as Hydrogen Sensing Material

Bannenberg,

Verhoeff,

Jonckers Newton

et al. 2024

ACS Appl. Nano Mater.

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Here, we study the structural and optical properties of tetragonal βtantalum-sputtered thin films both ex situ and when exposed to hydrogen, with a focus on optical hydrogen sensing applications. Using optical transmission measurements, out-of-plane and in-plane X-ray diffraction, and X-ray and neutron reflectometry, we show that thin film β-tantalum gradually, reversibly, and hysteresisfreely absorbs hydrogen with an increasing hydrogen pressure/concentration. The gradual absorption of hydrogen with increasing hydrogen concentrations induces a change in the optical transmission and reflection. These quantities change reversibly and are hysteresis-free over at least 5 orders of magnitude in hydrogen pressure/ concentration, making β-tantalum a suitable hydrogen sensing material. At all partial hydrogen pressures studied, we observe that the volumetric expansion, hydrogen-tometal ratio, and lattice expansion are substantially smaller than for body-centered cubic α-tantalum.

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Biocompatibility of new materials based on nano-structured nitinol with titanium and tantalum composite surface layers: experimental analysis in vitro and in vivo

Sevostyanov

Nasakina

Баикин

et al. 2018

J Mater Sci: Mater Med

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A technology for obtaining materials from nanostructured nitinol with titanium- or tantalum-enriched surface layers was developed. Surface layers enriched with titanium or tantalum were shown to provide a decrease in the formation of reactive oxygen species and long-lived protein radicals in comparison to untreated nitinol. It was determined that human peripheral vessel myofibroblasts and human bone marrow mesenchymal stromal cells grown on nitinol bases coated with titanium or tantalum-enriched surface layers exhibit a nearly two times higher mitotic index. Response to implantation of pure nitinol, as well as nano-structure nitinol with titanium or tantalum-enriched surface layers, was expressed though formation of a mature uniform fibrous capsule peripherally to the fragment. The thickness of this capsule in the group of animals subjected to implantation of pure nitinol was 1.5 and 3.0-fold greater than that of the capsule in the groups implanted with nitinol fragments with titanium- or tantalum-enriched layers. No signs of calcinosis in the tissues surrounding implants with coatings were observed. The nature and structure of the formed capsules testify bioinertia of the implanted samples. It was shown that the morphology and composition of the surface of metal samples does not alter following biological tests. The obtained results indicate that nano-structure nitinol with titanium or tantalum enriched surface layers is a biocompatible material potentially suitable for medical applications.

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Formation of alpha and beta tantalum at the variation of magnetron sputtering conditions

Cited by 13 publications

References 15 publications

Using of Magnetron Sputtering for Biocompatible Composites Creating

Using of Magnetron Sputtering for Biocompatible Composites Creating

Structural and Optical Properties of Thin Film β-Ta upon Exposure to Hydrogen to Asses Its Applicability as Hydrogen Sensing Material

Biocompatibility of new materials based on nano-structured nitinol with titanium and tantalum composite surface layers: experimental analysis in vitro and in vivo

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