Influence of noble metals alloying additions on the corrosion behaviour of titanium in a fluoride-containing environment

J Mater Sci Mater Med. 2012 May;23(5):1129-37. doi: 10.1007/s10856-012-4591-9. Epub 2012 Mar 2.

Abstract

Titanium alloys exhibit excellent corrosion resistance in most aqueous media due to the formation of a stable oxide film, and some of these alloys (particularly Ti-6Al-7Nb) have been chosen for surgical and odontological implants for their resistance and biocompatibility. Treatment with fluorides (F(-)) is known to be the main method for preventing plaque formation and dental caries. Toothpastes, mouthwashes, and prophylactic gels can contain from 200 to 20,000 ppm F(-) and can affect the corrosion behaviour of titanium alloy devices present in the oral cavity. In this work, the electrochemical corrosion behaviour of Ti-1M alloys (M = Ag, Au, Pd, Pt) was assessed in artificial saliva of pH = 3.0 containing 910 ppm F(-) (0.05 M NaF) through open circuit potential, E(OC), and electrochemical impedance spectroscopy (EIS) measurements. The corrosion behaviour of the Ti-6Al-7Nb commercial alloy was also evaluated for comparison. E (OC) measurements show an active behaviour for all the titanium alloys in fluoridated acidified saliva due to the presence of significant concentrations of HF and HF(2) (-) species that dissolve the spontaneous air-formed oxide film giving rise to surface activation. However, an increase in stability of the passive oxide layer and consequently a decrease in surface activation is observed for the Ti-1M alloys. This behaviour is confirmed by EIS measurements. In fact, the Ti-6Al-7Nb alloy exhibits lower impedance values as compared with Ti-1M alloys, the highest values being measured for the Ti-1Au alloy. The experimental results show that the corrosion resistance of the studied Ti-1M alloys is similar to or better than that of Ti-6Al-7Nb alloy currently used as biomaterial, suggesting their potential for dental applications.

Publication types

  • Evaluation Study

MeSH terms

  • Alloys / chemical synthesis
  • Alloys / chemistry*
  • Alloys / pharmacology
  • Cariostatic Agents / pharmacology
  • Coated Materials, Biocompatible / chemistry
  • Coated Materials, Biocompatible / pharmacology
  • Coordination Complexes / chemical synthesis
  • Coordination Complexes / chemistry*
  • Corrosion
  • Electric Impedance
  • Environment
  • Fluoridation
  • Fluorides / chemistry
  • Fluorides / pharmacology*
  • Gold / chemistry
  • Gold / pharmacology
  • Materials Testing
  • Palladium / chemistry
  • Palladium / pharmacology
  • Platinum / chemistry
  • Platinum / pharmacology
  • Silver / chemistry
  • Silver / pharmacology
  • Titanium / chemistry*

Substances

  • Alloys
  • Cariostatic Agents
  • Coated Materials, Biocompatible
  • Coordination Complexes
  • Ti-6Al-7Nb alloy
  • Silver
  • Platinum
  • Palladium
  • Gold
  • Titanium
  • Fluorides