Surface Characterization of NiTi Superelastic and Shape Memory Alloys After Electrolytic Polishing

Lopes, Natália Isabel de Azevedo; Silva, Laís Ávila de Oliveira; Santos, Leandro de Arruda; Buono, Vicente Tadeu Lopes

doi:10.1590/1980-5373-mr-2016-0933

Cited by 23 publications

(9 citation statements)

References 22 publications

(34 reference statements)

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“…The second group of samples was electropolished between the cleansing and coating steps. The electropolishing was carried out using a 3.5 mol•L -1 H 2 SO 4 in methanol electrolyte, setting the potential at 7 V, for 240 seconds 9 .…”

Section: Methodsmentioning

confidence: 99%

“…Moreover, surface defects and localized corrosion points act as stress concentrators, which can initiate cracking and cause premature failure of biodevices [10][11][12] . The electrochemical techniques of surface modification, such as polishing and deposition, stand out because they significantly improve the properties of Ni-Ti alloys, and present low cost and high reproducibility 9,10 . Figure 3 illustrates the surface morphologies of the Ni-Ti wire in the as-received state and after electropolishing.…”

Section: Substrate Characterization and Surface Preparationmentioning

confidence: 99%

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ToF-SIMS Characterization of Nanostructured ZrO2 Coatings Applied to Near Equiatomic Ni-Ti Alloy

et al. 2019

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The ToF-SIMS technique was applied to analyze thin ZrO 2 coatings deposited on the surface of a Ni-Ti alloy. Due to its nanostructured nature, these films are difficult to characterize by conventional techniques. ZrO 2 coatings were deposited on near equiatomic Ni-Ti wires by pulse electrodeposition. Part of the samples was electrolytically polished before the coating process. The coated samples were then analyzed by ToF-SIMS to evaluate the influence of the deposition time and previous surface electropolishing on the structure of the deposited coating. The results indicate that thicker coatings were produced on the electropolished samples, in comparison with the as-received ones. The best uniformity in thickness was achieved when Ni-Ti samples were previously electropolished followed by ZrO 2 electrodeposition for 1200 seconds. Moreover, it was possible to observe by this technique that the inclusions in the Ni-Ti matrix were not entirely covered by the coating.

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Section: Methodsmentioning

confidence: 99%

Section: Substrate Characterization and Surface Preparationmentioning

confidence: 99%

ToF-SIMS Characterization of Nanostructured ZrO2 Coatings Applied to Near Equiatomic Ni-Ti Alloy

et al. 2019

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“…Ti is noble than (Ni) so that, the oxide is accepted to be completely of (TiO2). On the other hand, at shorter wave length (532nm) will decreases the current density at same conditions this means that more heat will transfer to the substrate which in turn enhance the building rate of the protective oxide layer [22].…”

Section: Corrosion Testmentioning

confidence: 99%

Effect of Laser Surface Treatment on Transition Temperature of Ni/Ti SMAS

Salih¹,

Khaqani²

2021

IJHT

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It is well established that SMAs have a great important as: engineering and biomaterial applications, because of unique properties that had as well as, good biocompatibility. however, duo to its possible corrosion in physiological solution, dissolution of toxic Ni might be happening. Several studies have been carried out to improve the stability of the passive protective film of Tio2 and prevent the Ni ion relies out of NiTi. Surface treatment is one of these methods or techniques such as, ion implantation, plasma electro polishing, passivation, ultra-sonic treatment and laser treatment, most of these treatments are effects on transition temperatures (As,Af,Ms,Mf). Change of these temps. will affected the normal use especially in human body, so keeping these temps. within the range of the human body is of main requirements to Evaluation the efficiency of any treatment. In this study (55 wt% Ni, 45 wt % Ti) SMAs has been prepared by (PM), compacted at 850 MPa and sintered. Laser pulses deposition technique at (1064, 532) nm at different energy (2, 2.3, 2.7) J. At power (200) wat in constant duration time (2 ns) has been used to modify surface by continuous stricks (side by side) to study mechanical, corrosion properties and how laser pulses effects on transition temp. All results confirmed that there is a positive effect on properties, % improving in hardness with respect to reference sample are (145, 132.8, 123.8) and (180.9, 169.5, 152.3) at 1064, 532 wave length respectively. Improvement in Ni relies are equal to (52, 38) % with respect to reference sample. On the other hand, there are slight positive change on transition martensitic transformation, thermal hysteries ( As−Ms) there are reduction in degress from 50°C (untreated sample) to (36.9, 33.6)°C, while for martensitic transformation ( Af−Mf) the degress are decrease from (65)°C for untreated sample to (57.5, 51.7)°C wave length respectively.

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“…O polimento eletrolítico foi realizado utilizando uma célula eletroquímica padrão, com um contraeletrodo de platina e um eletrodo de referência Ag|AgCl, ligados a um potenciostato (VersaSTAT 3, Princeton Applied Research, Berwyn, EUA). O eletrólito utilizado é constituído por uma solução 21% de ácido sulfúrico (H 2 SO 4 ) em metanol (CH 3 OH), que apresentou bons resultados no polimento de ligas NiTi em estudo anterior [9,10]. O potencial aplicado de 7 V, durante o tempo de 240 segundos.…”

Section: Materiais E Métodosunclassified

Efeitos Da Densidade De Corrente Na Morfologia De Revestimenos De Zircônia Eletrodepositados Em Niti

Pagotto¹,

Lopes²,

Silva³

et al. 2019

ABM Proceedings

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Revestimentos de zircônia possuem boa resistência à corrosão e ao desgaste, além de biocompatibilidade. Desse modo, se apresentam como boa alternativa para a proteção contra a corrosão e a degradação de ligas NiTi utilizadas como biomateriais, com o potencial de evitar os efeitos alergênicos causados pela liberação de íons níquel no organismo e de diminuir os riscos de falhas durante seu uso. Neste estudo, a influência da densidade de corrente na morfologia dos revestimentos obtidos por eletrodeposição em uma liga NiTi superelástica foi avaliada. A eletrodeposição foi feita usando dois eletrólitos aquosos de sais distintos: Zr(NO 3) 2 e ZrOCl 2 , nas condições encontradas na literatura e variando os valores de densidade de corrente aplicados. Para caracterização foram realizadas análises por MEV, EDX e DRX. Usando o eletrólito de Zr(NO 3) 2 e corrente de 5 mA•cm-2 , o revestimento obtido mostrou-se heterogêneo e, para todos os valores de corrente, o teor de Zr detectado foi muito baixo. Quando o eletrólito de ZrOCl 2 foi utilizado, os teores de Zr detectados foram mais altos e as diferenças entre os revestimentos obtidos foram mais sutis. Melhor aspecto superficial e maior teor de Zr foram obtidos usando corrente de 3 mA•cm-2 e o eletrólito de ZrOCl 2 .

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Surface Characterization of NiTi Superelastic and Shape Memory Alloys After Electrolytic Polishing

Cited by 23 publications

References 22 publications

ToF-SIMS Characterization of Nanostructured ZrO2 Coatings Applied to Near Equiatomic Ni-Ti Alloy

ToF-SIMS Characterization of Nanostructured ZrO2 Coatings Applied to Near Equiatomic Ni-Ti Alloy

Effect of Laser Surface Treatment on Transition Temperature of Ni/Ti SMAS

Efeitos Da Densidade De Corrente Na Morfologia De Revestimenos De Zircônia Eletrodepositados Em Niti

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