Bing Liu

Magnesium alloy represents a typical category of biodegradable medical materials. However, the poor corrosion resistance and rapid degradation have significantly hindered the clinical adoption of magnesium alloy implants. This paper puts forward a method to improve the corrosion resistance of magnesium alloy by using an Fe-based composite coating. The microstructure and composition of the coating were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive spectroscopy (EDS). The corrosion resistance was evaluated through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements conducted in simulated body fluid, while the degradation behavior of the samples was evaluated by examining the hydrogen evolution volume and corrosion morphology during immersion tests. The results indicate that the composite coating exhibits a dual-layer structure, consisting of an amorphous carbon–fluorine transition layer and an iron-rich surface layer. After coating treatment, the corrosion current density of magnesium alloy decreased from 1.38 × 10⁻⁴ to 3.41 × 10⁻⁶ A/cm². Throughout a 28-day immersion period, the composite-coated sample demonstrated a remarkably low hydrogen evolution rate and maintained a smooth, intact surface. Furthermore, hemolysis and platelet adhesion tests confirmed the outstanding blood compatibility of the composite-coated magnesium alloy, showing an ultralow hemolysis rate of 0.1% and minimal platelet adhesion with well-preserved morphology.

Based on the clustering effect of shear-thickening fluids (STFs), a high-shear low-pressure flexible grinding wheel has been developed. In order to explore the material removal mechanism, the coupled Eulerian—Lagrangian (CEL) method is adopted to simulate the novel grinding process. The simulation results show that particle clustering effects do occur at the tangential and bottom positions of the micro-convex peak when it instantaneously strikes the workpiece surface. The particle clusters drive the harder abrasive particles to resist the strong interactions of micro-convex peaks. The micro-convex peaks are removed due to the cutting effect of the harder abrasive particles. Compared with traditional grinding, the ratio of tangential force to normal force for the high-shear low-pressure flexible grinding wheel is improved. The various trends in force ratio are consistent with the experimental results, which verifies the effectiveness of high-shear low-pressure grinding.