J.B. Li

Simulated body fluid electrochemical response of Zr-based metallic glasses with different degrees of crystallization.

The bio-electrochemical response in simulated body fluid of the Zr53Cu30Ni9Al8 metallic glasses with different degrees of partial crystallization was systematically examined and discussed. Through thermal annealing, the volume fractions of the crystalline phases are determined to be 0, 34, 63, and near 100%. Based on the bio-corrosion voltage and current, as well as the polarization resistance, it is concluded that the fully amorphous alloy exhibits the highest bio-electrochemical resistance. With an increasing degree of partial crystallization, the corrosion resistance becomes progressively degraded. The passive current reveals that the fully amorphous metallic glasses can form a more protective and denser passive film on the metallic glass surface. The formation of reactive nanocrystalline phases in the amorphous matrix would reduce the bio-corrosion resistance.

Electrochemical and biocompatibility response of newly developed TiZr-based metallic glasses.

This paper presents systematical investigations, including electrochemical activity, MTT cell assay and in vivo test, on the biocompatibility of three metallic glasses. The electrochemical behaviors and the cell toxicity of two newly developed TiZr-based metallic glasses (MGs), Ti42Zr40Si15Ta3 and Ti40Zr40Si15Cu5, with lower or without unfavorable elements are systematically investigated. Results show that the MGs with low Cu content exhibit a low electrochemical response. Cytotoxicity tests for the MGs and the mediums after the potential state test are evaluated with in vitro MTT assays. The solid specimens and the mediums after the potential state test for the pure Ti, Ti42Zr40Si15Ta3 and Ti40Zr40Si15Cu5 exhibit no significant cytotoxicity in the MTT test, while the tested medium for Ti45Cu35Zr20 MG shows lower cell viability. The inductively coupled plasma-mass spectrometry (ICP-MS) results also indicate that the Cu-rich sample released a significant amount of ions which may be the major factor causing the low viability in the MTT test. The good healing condition and the low C-reactive protein (CRP) index for the implanted New Zealand rabbits in a one-month in vivo test also show the satisfactory short-term biocompatibility of the TiZr-based MGs. The electrochemical measurements, in vitro, and in vivo experiments confirm that the developed TiZr-based MGs with lower Cu content (≦5%) are promising for biomedical purposes.