Surface modification with SiO2 coating onbiomedical TiNi shape memory alloy by sol-gel method
(1. Department of Otolaryngology of the Second Xiangya Hospital, Central South University, Changsha 410011, China;
2. Department of Otolaryngology of the Third Hospital of Changsha, Changsha 410015, China;
3. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
4. Department of Gynaecology and Obstetrics of the Third Xiangya Hospital,
Central South University, Changsha 410013, China;
5. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
2. Department of Otolaryngology of the Third Hospital of Changsha, Changsha 410015, China;
3. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
4. Department of Gynaecology and Obstetrics of the Third Xiangya Hospital,
Central South University, Changsha 410013, China;
5. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
Abstract: The effect of heat treatment on the transformationtemperature of Ti-52.2%Ni (mole fraction) alloy was studied using differential scanning calorimetry (DSC). The transformation temperatures of the alloy can be adjusted effectively by heat treatment. Dense and stable SiO2 coatings were deposited on the surface of the pre-oxidized TiNi alloy by sol-gel method. The bonding strength of films and matrix was (65.9±1.5) N. The electrochemical corrosion test shows that the TiNi alloy with SiO2 coating has excellentcorrosionresistance in the Hank’s simulated body fluid. The release behaviors of Ni ion of the alloy with and without SiO2 coating implanted in the acoustic vesicle of guineapig were studied by EDS testing, which was inhibited effectively by the dense and stable SiO2 coating on the alloy.
Key words: TiNi shape memory alloy; surface modification; SiO2 coating; corrosionresistance; biocompatibility