dc.description.abstract | In recent years, biomedical bone nails and suture rivets and other orthopedic implants made of biodegradable materials have attracted considerable attention, especially magnesium-based metallic glass. Because Mg-based metallic glass has good mechanical properties, similar Young′s modulus to human bones, and good biocompatibility compared with the other traditional biomedical materials or magnesium alloys. Bulk metallic glass material has no grain boundaries which can decrease the degradation rate of the implant material in comparison with Mg alloys and suitable for orthopedic implants.
However, the metallic glass is lack of toughness limited the workability via machining and application. Therefore, this study chooses magnesium alloy ZK60 as the base material. The ZK60 plates coated with 1000 nm metallic glass thin film (MGTF) by DC-sputtering to improve the mechanical properties, corrosion resistance and biocompatibility.
The results show that the structure of the coated Mg-based MGTF is amorphous state by DC-sputtering. According to the tape adhesion test results, the adhesion of the Mg-based MGTF is 5B class (0% of the film peels off the base material). Through the Nanoindentation test, it can be observed that the hardness of the Mg-based MGTF is 240 Hv (about twice that of ZK60). The results of 3-point bending test show that the Mg-based MGTF can effectively improve the bending strength. When the thin film thickness is about 1000 nm, the bending strength can be increased from 216 MPa to 254 MPa compare with the ZK60 base materials. Because MGTF has a higher hardness, it can increase the bending strength. And the Mg-based MGTF thickness of 1000 nm under different powers has the same bending strength. In addition, through the electrochemical corrosion test (dynamic polarization curve), the 30W Mg-based MGTF has the best corrosion resistance, and its corrosion current is 1.51 × 10-7 A/cm2 relative to ZK60′s 4.88 × 10-6 A/cm2 is about 3/100 times. When corrosion occurs, the corrosion rate will be much smaller than that of ZK60, and the 30W Mg-based MGTF can find a larger passivation area. The results of the electrochemical corrosion test show that the Mg-based MGTF can provide better corrosion resistance to protect the ZK60 substrate. | en_US |