title: [Effect of chloride ion on corrosion of two commonly used dental alloys].
abstract: OBJECTIVE
  To investigate the eff ect of chloride concentration on the corrosion of Co-Cr alloy and pure Ti in a simulated oral environment.
  
  
  METHODS
  The electrochemical corrosion tests of pure Ti and Co-Cr alloy were carried out in neutral artificial saliva solutions with different NaCl concentrations (0.9%, 2.0%, and 3.0%). Th e morphologies of corroded surface for pure Ti and Co-Cr alloy were observed by scanning electron microscope (SEM).
  
  
  RESULTS
  Th e changes in the self-corrosion potentials (Ecorr) for pure Ti and Co-Cr alloy in three kinds of artificial saliva solutions was not obvious. However, the self-corrosion current densities (Icorr) of pure Ti were much lower than those of Co-Cr. The Icorr of Co-Cr alloy increased in a concentration-dependent manner of NaCl, whereas the breakdown potential (Eb) of Co-Cr alloy decreased in a concentration-dependent manner. Th e potential ranged for the breakdown of oxide film (Ev) was shortened in a concentration-dependent manner of NaCl. There was no obvious difference in the Icorr of pure Ti with different concentrations of NaCl. The breakdown potential was not seen according to the polarization curves.
  
  
  CONCLUSIONS
  In a certain range, the increase of the concentration of Cl- leads to accelerate the corrosion behavior of Co-Cr alloy, but it does not affect pure Ti.
authors.affiliation: Center of Stomatology, Xiangya Hospital of Central South University, Changsha 410008, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Weidan
authors.initials: W
authors.lastname: Zhang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D002712:Chlorides / Q000737:chemistry*; D002857:Chromium; D003035:Cobalt; D003343:Corrosion; D003722:Dental Alloys / Q000737:chemistry*; D012464:Saliva, Artificial; D013499:Surface Properties; D014025:Titanium
chemical_list: D002712:Chlorides; D003722:Dental Alloys; D012464:Saliva, Artificial; D002857:Chromium; D003035:Cobalt; D014025:Titanium