Oxide Formation on NiTi Surface: Influence of the Heat Treatment Time to Achieve the Shape Memory

Hansen, Alana Witt; Beltrami, Lílian Vanessa Rossa; Antonini, Leonardo Marasca; Villarinho, Denis Jardim; Neves, Julio Cesar Klein das; Marino, Cláudia Eliana Bruno; Malfatti, Célia de Fraga

doi:10.1590/1516-1439.022415

Cited by 27 publications

(8 citation statements)

References 22 publications

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“…On the basis of literature reports, it was confirmed that the results of oxide layer thickness measurements were carried out correctly. [11]. The results show a dependence that more extended mechanical activation contributes to the increase of surface development, and thus to the increase of the oxide layer thickness -as can be seen for glass beads and sandpapergrits -40 and 180.…”

Section: Resultsmentioning

confidence: 53%

Change in the surface structure and the oxide layer of the Ti6Al4V ELI alloy as a result of mechanical and heat treatment

Szota

2021

iboa

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Surface treatment, both mechanical, chemical and thermal causes a number of changes to the external structure of meterial details. The obtained properties are intended to improve the quality of material details made of a given alloy or pure metal. This paper presents the results of mechanical surface treatment to the thickness of the oxide layer after heat treatment of the TU6Al14V ELI alloy. The experiments were performed for a rod with a diameter of 5 mm cut into semicircular slices. The samples were mechanically activated by mechanical treatment of the surface: sandblasting with glass balls for 5 minutes, sanded with 40, 180, 220 and 800 grit sandpaper for 7.5 and 15 minutes.Using an optical microscope, the microstructure of the samples etched with Kroll's solution was assessed and the surface roughness parameters were measured.The next step was to carry out the heat treatment (at the temperature of 550 oC, for 5 hours), and then the roughness parameters and the thickness of the oxide layer were measured using a scanning microscope.The conducted research has shown that mechanical treatment of the surface resulting in an increase in surface development causes an increase in the thickness of the oxide layer formed during heat treatment. However, machining to reduce surface development, such as polishing, reduces the thickness of the oxide layer.The test results can be used to obtain the desired thickness of the oxide layer in the production of elements requiring increased resistance to wear or corrosion.

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Section: Resultsmentioning

confidence: 53%

Change in the surface structure and the oxide layer of the Ti6Al4V ELI alloy as a result of mechanical and heat treatment

Szota

2021

iboa

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“…27,28 The annealing process has increased the oxygen content %, as the heat during the annealing process increases the oxygen bonding with Titanium. 29 Furthermore, the presence of surface oxide enhances the cell adhesion due to increasing the surface energy (i.e., more hydrophilic) and surface wettability. Hence, in this study, the effects of laser welding parameters on the surface chemical composition of the laser-welded joint (e.g., local nickel content and the surface oxygen content) were investigated via EDS studies as crucial parameters for determining the biocompatibility.…”

Section: Discussionmentioning

confidence: 99%

Assessment of mechanical and biocompatible performance of ultra-large nitinol endovascular devices fabricated via a low-energy laser joining process

et al. 2021

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Nitinol is an excellent candidate material for developing various self-expanding endovascular devices due to its unique properties such as superelasticity, biocompatibility and shape memory effect. A low-energy laser joining technique suggests a high potential to create various large diameter Nitinol endovascular devices that contain complex geometries. The primary purpose of the study is to investigate the effects of laser joining process parameters with regard to the mechanical and biocompatible performance of Nitinol stents. Both the chemical composition and the microstructure of the laser-welded joints were evaluated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). In vitro study results on cytotoxicity demonstrated that the joining condition of 8 Hz frequency and 1 kW laser power showed the highest degree of endothelial cell viability after thermal annealing in 500°C for 30 min. Also, in vitro study results showed the highest oxygen content at 0.9 kW laser power, 8 Hz frequency, and 0.3 mm spot size after the thermal annealing. Mechanical performance test results showed that the optimal condition for the highest disconnecting force was found at 1 Hz frequency and 1 kW power with 0.6 mm spot size. Two new endovascular devices have been fabricated using the optimized laser joining parameters, which have demonstrated successful device delivery and retrieval, as well as acute biocompatibility.

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“…Atmospheric oxygen has strong affinity for Ti, forming a passive layer of oxide on its surface, which serves as a protective layer against corrosion. The thickness of this oxide layer may undergo some changes according to environmental conditions and treatment (Hansen et al, 2015). Recently, Mohan et al (2017) evaluated chemical compositions of surface composed by Ni, Ti and O on NiTi alloy substrates subjected to O-PIII technique.…”

Section: Discussionmentioning

confidence: 99%

Osteogenesis and biofilms formation on titanium surfaces submitted to oxygen plasma immersion ion implantation

Tini

Araújo

Gonçalves

et al. 2021

RSD

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The objectives of this study were to characterize titanium (Ti) surfaces treated by ion implantation by immersion in oxygen plasma (O-PIII) at different temperatures, correlating these implanted layers with therapeutic effects and with osteogenesis, as well as the formation of monotypic biofilms microbial. The groups were divided into: a) Ti (pre-treatment) b) Ti O-PIII at 400 ° C. c) Ti O-PIII at 500 ° C. d) Ti O-PIII at 600 ° C. The properties and surface characteristics were evaluated according to the roughness, texture, corrosion resistance, formation of new phases and the identification of chemical compounds present. Cellular analyzes investigated cell interaction, viability, total protein content, alkaline phosphatase and quantification of mineralized nodules using MG-63 cells. The formation of monotypic microbial biofilms, including P. aeruginosa, S. aureus, S. mutans and C. albicans were evaluated. The increase in surface roughness, corrosion resistance and oxygen content, leading to the formation of TiO2-rutile with more intense peaks and in greater numbers according to the increase in the substrate temperature, ionic implanted Ti samples was observed. There was also a significant increase in cell viability, total protein production, alkaline phosphatase activity and formation of mineralization nodules for the group treated with O-PIII at 600ºC compared to other groups, in addition to a reduction of microorganisms in the groups treated with O- PIII. Therefore, treatment with O-PIII at 600ºC in Ti grade IV showed favorable results for its use.

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Oxide Formation on NiTi Surface: Influence of the Heat Treatment Time to Achieve the Shape Memory

Cited by 27 publications

References 22 publications

Change in the surface structure and the oxide layer of the Ti6Al4V ELI alloy as a result of mechanical and heat treatment

Change in the surface structure and the oxide layer of the Ti6Al4V ELI alloy as a result of mechanical and heat treatment

Assessment of mechanical and biocompatible performance of ultra-large nitinol endovascular devices fabricated via a low-energy laser joining process

Osteogenesis and biofilms formation on titanium surfaces submitted to oxygen plasma immersion ion implantation

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