Biocorrosion study of titanium-nickel alloys

The present study provides results of the corrosion behaviour in Hank's physiological solution and some other properties of three Ti-Ni alloys with 18, 25 and 28.4 wt% Ni, respectively. Results indicate that α-titanium and Ti₂Ni were the two major phases in all three Ti-Ni alloys. The relative amount of the Ti₂Ni phase increased with additional Ni content. Hardness of the Ti-Ni alloys also increased with added nickel content, ranging from 310 to 390 VHN, similar to the hardness of enamel. Melting temperatures of the Ti-Ni alloys were all lower than that of pure titanium by least 600°C. The three Ti-Ni alloys behaved almost identically when potentiodynamically polarized in Hank's solution at 37°C. The critical anodic current densities of the alloys were nearly 30 μA/cm²3 and the breakdown potentials were all above 1100 mV (SCE).