Effects of titanium nitride coatings on surface and corrosion characteristics of Ni-Ti alloy.
The structure of a titanium nitride film coated by arc ion plating on a Ni-50Ti shape memory alloy was characterized by X-ray photoelectron spectroscopy (XPS). The corrosion behavior of the titanium nitride-coated Ni-50Ti alloy was examined in 0.9% NaCl solution by potentiodynamic polarization measurements and a polarization resistance method. XPS spectra showed that the titanium nitride film consisted of three layers, a top layer of TiO2, a middle layer of TiNx (x > 1), and an inner layer of TiN. The passive current density for the titanium nitride-coated alloy was approximately two orders of magnitude lower than that of the polished alloy in the potential range from the free corrosion potential to +500 mV (vs. Ag/AgCl). Pitting corrosion associated with breakdown of the coated film occurred above this potential. The polarization resistance data also indicated that the corrosion rate of the titanium nitride-coated alloy at the free corrosion potential (+50-+100 mV) was more than one order of magnitude lower than that for the polished alloy.
Endo
K
K
Department of Dental Materials Science, School of Dentistry, Health Sciences University of Hokkaido, Japan.
Sachdeva
R
R
Araki
Y
Y
Ohno
H
H
D003343:Corrosion; D003722:Dental Alloys / Q000737:chemistry*; D004563:Electrochemistry; D004595:Electroplating; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
D003722:Dental Alloys; C040654:titanium nickelide; C041500:titanium nitride; D009532:Nickel; D014025:Titanium