Corrosion behaviour of titanium after short-term exposure to an acidic environment containing fluoride ions.
The negative effect of fluoride ions on titanium has been known in dentistry for a long time. The presented work was aimed at the interaction between titanium and model saliva following a short-term exposure of a specimen to a model medical preparation rich in fluoride ions. The experimental work was carried out using titanium grade 2 in a physiological solution (pH non-adjusted, 5.8, 4.2; 5000 ppm F-) and in model saliva. Electrochemical measurement techniques were supplemented with XPS analysis. The presence of fluoride ions resulted in partial degradation of the passive layer even in a slightly acidic environment. The decrease of pH to the value of 4.2 and the presence of 5000 ppm F- caused titanium activation followed by a slow repassivation in model saliva. Formation of low soluble compound rich in fluorine explains experimental data. Short medical treatment can result in relatively long period of increased titanium corrosion.
Joska
Ludek
L
Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Technicka 5, 166 28 Prague 6, Czech Republic. Ludek.Joska@vscht.cz
Fojt
Jaroslav
J
D000143:Acids / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D040761:Biomimetic Materials / Q000737:chemistry; D003343:Corrosion; D005459:Fluorides / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008422:Materials Testing; D012463:Saliva / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
D000143:Acids; D001672:Biocompatible Materials; D007477:Ions; D014025:Titanium; D005459:Fluorides