Abstract: The corrosion rates and anodic polarization behavior of TiNi shape memory alloy, CoCrNiMo and CoCrNiW biomedical materials were studied respectively by linear polarization and potentiodynamic scanning techniques. The results show that three alloys have excellent corrosion resistance with the extensive passive region and low passive current density. The hysteresis loop and SEM morphology show that cobalt based alloys exhibit better resistance to pitting corrosion, while TiNi is very susceptible to it. It is due to the Ti2Ni inclusions on the surface which is easily attacked by active anion Cl-, but in cobalt based alloys the element Co, Cr, Mo and W can form passive oxide film which inhibits pitting corrosion. The measurement of contact angle, dynamic clotting time and hemolysis rate indicate that the haemocompatibility of TiNi is the best, which is perhaps attributed to the small surface tension of TiO2 film.
Corrosion behavior and haemocompatibility of TiNi shape memory alloy and cobalt-based alloys
Abstract:
The corrosion rates and anodic polarization behavior of TiNi shape memory alloy, CoCrNiMo and CoCrNiW biomedical materials were studied respectively by linear polarization and potentiodynamic scanning techniques. The results show that three alloys have excellent corrosion resistance with the extensive passive region and low passive current density. The hysteresis loop and SEM morphology show that cobalt based alloys exhibit better resistance to pitting corrosion, while TiNi is very susceptible to it. It is due to the Ti 2Ni inclusions on the surface which is easily attacked by active anion Cl -, but in cobalt based alloys the element Co, Cr, Mo and W can form passive oxide film which inhibits pitting corrosion. The measurement of contact angle, dynamic clotting time and hemolysis rate indicate that the haemocompatibility of TiNi is the best, which is perhaps attributed to the small surface tension of TiO 2 film.[