title: Effect of plasma nitriding and titanium nitride coating on the corrosion resistance of titanium.
abstract: BACKGROUND
  The passive film on the surface of titanium can be destroyed by immersion in a fluoridated acidic medium. Coating with titanium nitride (TiN) may improve the corrosion resistance of titanium.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to investigate the effect of duplex treatment with plasma nitriding and TiN coating on the corrosion resistance of cast titanium.
  
  
  METHODS
  Cast titanium was treated with plasma nitriding and TiN coating. The corrosion resistance of the duplex-treated titanium in fluoride-containing artificial saliva was then investigated through electrochemical and immersion tests. The corroded surface was characterized by scanning electron microscopy (SEM) with energy-dispersive spectroscopy surface scan analysis. The data were analyzed using ANOVA (α=.05) RESULTS: Duplex treatment generated a dense and uniform TiN film with a thickness of 4.5 μm. Compared with untreated titanium, the duplex-treated titanium displayed higher corrosion potential (Ecorr) values (P<.001) and lower corrosion current density (Icorr) values (P<.001). SEM results showed that the surface of untreated titanium was more heavily corroded than that of duplex-treated titanium. Surface scan analysis of duplex-treated titanium that had been immersed in artificial saliva containing 2 g/L fluoride revealed fluorine on the titanium surface, whereas fluorine was not observed on the surface of untreated titanium after immersion in fluoride-containing artificial saliva. The concentration of titanium ions released from the treated titanium was less than the amount released from untreated titanium (P<.001).
  
  
  CONCLUSIONS
  Duplex treatment by plasma nitriding and TiN coating significantly improved the corrosion resistance of cast titanium in a fluoride-containing environment.
authors.affiliation: Assistant Professor, Department of Prosthodontics, Anyang Sixth People's Hospital, Anyang, China.
authors.forename: Xianli
authors.initials: X
authors.lastname: Wang
authors.affiliation: Associate Professor, State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
authors.forename: Shizhu
authors.initials: S
authors.lastname: Bai
authors.affiliation: Assistant Professor, State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Li
authors.affiliation: Associate Professor, State Key Laboratory of Military Stomatology, Department of VIP Dental Care, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Li
authors.affiliation: Associate Professor, Department of Orthodontics, Anyang Sixth People's Hospital, Anyang, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Assistant Professor, State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
authors.forename: Min
authors.initials: M
authors.lastname: Tian
authors.affiliation: Assistant Professor, State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Associate Professor, State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Tong
authors.affiliation: Assistant professor, State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
authors.forename: Zichuan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Assistant Professor, State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
authors.forename: Guowei
authors.initials: G
authors.lastname: Wang
authors.affiliation: Professor, State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
authors.forename: Tianwen
authors.initials: T
authors.lastname: Guo
authors.affiliation: Associate Professor, State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China. Electronic address: machufan@fmmu.edu.cn.
authors.forename: Chufan
authors.initials: C
authors.lastname: Ma
mesh_terms: D003343:Corrosion; D005459:Fluorides / Q000009:adverse effects; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D012464:Saliva, Artificial / Q000009:adverse effects; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties; D014025:Titanium / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D012464:Saliva, Artificial; C041500:titanium nitride; D014025:Titanium; D005459:Fluorides