Hh. Huang, Effects of fluoride concentration and elastic tensile strain on the corrosion resistance of commercially pure titanium, BIOMATERIAL, 23(1), 2002, pp. 59-63
The corrosion resistance of commercially pure (CP) titanium in 1% NaCl divi
ded by 0 similar to 1% NaF solution (pH = 6) under different elastic tensil
e strains was investigated by using electrochemical impedance spectroscopy
(EIS) measurement technique. The polarization resistance (Rp), which is inv
ersely proportional to the corrosion rate, of CP titanium in the test solut
ion was obtained from the EIS data. Different elastic tensile strains, name
ly 0%, 1%, 2%, and 4%, were applied on the test specimens by using a tensil
e test machine during the corrosion tests. Corrosion morphology was charact
erized by using a scanning electron microscope. Surface chemical analyses w
ere performed by using energy dispersive spectroscopy and X-ray photoelectr
on spectroscopy. The results showed that the NaF concentration and the elas
tic tensile strain had a statistically significant influence on the R-p (P
<0.001). The R-p decreased on increasing the NaF concentration and the elas
tic tensile strain. When the NaF concentration was lower than 0.01 %, the R
-p value ( > 3.4 x 10(5) Omega cm(2)) was mainly ascribed to the formation
of a protective titanium dioxide (TiO2) on the metal surface, regardless of
the elastic tensile strain applied. However, when the NaF concentration wa
s higher than 0. 1%, the protectiveness of TiO2 was destroyed by fluoride i
ons, leading to severe corrosion of CP titanium. (C) 2001 Elsevier Science
Ltd. All rights reserved.