TY - JOUR
T1 - Effect of titanium nitride/titanium coatings on the stress corrosion of nickel-titanium orthodontic archwires in artificial saliva
AU - Liu, Jia Kuang
AU - Liu, I. Hua
AU - Liu, Cheng
AU - Chang, Chen Jung
AU - Kung, Kuan Chen
AU - Liu, Yen Ting
AU - Lee, Tzer Min
AU - Jou, Jin Long
N1 - Funding Information:
This study was supported by the Southern Taiwan Science Park Administration (STSPA), Taiwan under contract 102CB02 .
Publisher Copyright:
© 2014 Elsevier B.V. All rights reserved.
PY - 2014/10/30
Y1 - 2014/10/30
N2 - The purpose of this investigation was to develop titanium nitride (TiN)/titanium (Ti) coating on orthodontic nickel-titanium (NiTi) wires and to study the stress corrosion of specimens in vitro, simulating the intra-oral environment in as realistic a manner as possible. TiN/Ti coatings were formed on orthodontic NiTi wires by physical vapor deposition (PVD). The characteristics of untreated and TiN/Ti-coated NiTi wires were evaluated by measurement of corrosion potential (E corr ), corrosion current densities (I corr ), breakdown potential (E b ), and surface morphology in artificial saliva with different pH and three-point bending conditions. From the potentiodynamic polarization and SEM results, the untreated NiTi wires showed localized corrosion compared with the uniform corrosion observed in the TiN/Ti-coated specimen under both unstressed and stressed conditions. The bending stress influenced the corrosion current density and breakdown potential of untreated specimens at both pH 2 and pH 5.3. Although the bending stress influenced the corrosion current of the TiN/Ti-coated specimens, stable and passive corrosion behavior of the stressed specimen was observed even at 2.0 V (Ag/AgCl). It should be noted that the surface properties of the NiTi alloy could determine clinical performance. For orthodontic application, the mechanical damage destroys the protective oxide film of NiTi; however, the self-repairing capacity of the passive film of NiTi alloys is inferior to Ti in chloride-containing solutions. In this study, the TiN coating was found able to provide protection against mechanical damage, while the Ti interlayer improved the corrosion properties in an aggressive environment.
AB - The purpose of this investigation was to develop titanium nitride (TiN)/titanium (Ti) coating on orthodontic nickel-titanium (NiTi) wires and to study the stress corrosion of specimens in vitro, simulating the intra-oral environment in as realistic a manner as possible. TiN/Ti coatings were formed on orthodontic NiTi wires by physical vapor deposition (PVD). The characteristics of untreated and TiN/Ti-coated NiTi wires were evaluated by measurement of corrosion potential (E corr ), corrosion current densities (I corr ), breakdown potential (E b ), and surface morphology in artificial saliva with different pH and three-point bending conditions. From the potentiodynamic polarization and SEM results, the untreated NiTi wires showed localized corrosion compared with the uniform corrosion observed in the TiN/Ti-coated specimen under both unstressed and stressed conditions. The bending stress influenced the corrosion current density and breakdown potential of untreated specimens at both pH 2 and pH 5.3. Although the bending stress influenced the corrosion current of the TiN/Ti-coated specimens, stable and passive corrosion behavior of the stressed specimen was observed even at 2.0 V (Ag/AgCl). It should be noted that the surface properties of the NiTi alloy could determine clinical performance. For orthodontic application, the mechanical damage destroys the protective oxide film of NiTi; however, the self-repairing capacity of the passive film of NiTi alloys is inferior to Ti in chloride-containing solutions. In this study, the TiN coating was found able to provide protection against mechanical damage, while the Ti interlayer improved the corrosion properties in an aggressive environment.
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U2 - 10.1016/j.apsusc.2014.08.132
DO - 10.1016/j.apsusc.2014.08.132
M3 - Article
AN - SCOPUS:84908205221
SN - 0169-4332
VL - 317
SP - 974
EP - 981
JO - Applied Surface Science
JF - Applied Surface Science
ER -