| In recent decades, biomedical metallic material is in the continuous development and innovation, and many new materials are developed and applicated in clinical successfully. Research into various magnesium alloys as a biodegradable implant material is gaining increasing attention due to their resemblance to cortical bone, degradability and perfect biocompatibility. However, the high degradation rate of it limits their clinical application. Surface modification is one of the most effective methods to improve corrosion resistance.laser surface processing Laser surface treatmen can greatly improve the fatigue corrosion resistance and alkaline treatment can greatly improve the corrosion resistance.Combination of the three, the mechanical properties of magnesium alloy and corrosion resistance become more perfect. This topic is dependent on biocompatibility, biomechanical compatibility, degradability,Mg-4.0Zn-1.5Sr were self-designed. After the laser surface processing and alkaline treatment on the Mg-4.0Zn-1.5Sr alloy sheet surface was prepared, the degradability and biocompatibility of the material were analyzed. Main results were as follows:(1) Optimal designed Mg-4.0Zn-1.5Sr alloys ingot was prepared, After magnesium alloy ingot is homogenizing annealing, and artificial aging. Medical magnesium alloy substrate with excellent performance is prepared.(2) The compared tests of corrosion resistance capability of Mg-4.0Zn-1.5Sr with homogenizing annealing and Mg-4.0Zn-1.5Sr alloys sheet with homogenizing annealing and artificial aging were carried out in the NaCl solution. The potential of Mg-4.0Zn-1.5Sr with homogenizing annealing is-1.5315V and the current is 687uA. The potential of Mg-4.0Zn-1.5Sr with homogenizing annealing and artificial aging is-1.5062V and the current is 566uA. And the result is consistent with the weight loss method.(3) The compared tests of corrosion resistance capability of Mg-4.0Zn-1.5Sr alloys sheet with homogenizing annealing and artificial aging were carried out in the NaCl solution and SBF solution. The corrosion resistance capability of SBF solution is better than NaCl solution.(4) The Mg-4.0Zn-1.5Sr alloy sheet were sevred as the matrix to be treated by the laser surface processing and alkaline treatment.The optimal parameters of laser surface processing are that the power is 3kW,the current is 200A, the width is lmm, the defocus amount is 135mm and the scanning speed is lmm/s, The optimal parameters of alkaline treatment are that the solution is NaOH,the concentration is 0.5mol/L, the temperature is 80℃ and the best time was 12h.(5) The potential of Mg-4.0Zn-1.5Sr with laser surface processing is-1.4995V and the current is 479uA. The potential of Mg-4.0Zn-1.5Sr with alkaline treatment is-1.3718V and the current is 8.803uA. its corrosion rate were lower than the alloy with laser surface processing and without surface treatment, the corrosion resistance is greatly improved.(6) The hemolysis ratios of Mg-4.0Zn-1.5Sr cultured for 1d,3d,5d is 1.04%, 0.8%,4.56%.The hemolysis ratios of Mg-4.0Zn-1.5Sr with laser surface processing and alkaline treatment cultured for 1d,3d,5d is 0.633%,1.24%,0.83%, They are all lower than 5%. For the pH, The pH of Mg-4.0Zn-1.5Sr cultured for Id,3d,5d is 12.42,13.02,12.94, The pH of Mg-4.0Zn-1.5Sr with laser surface processing and alkaline treatment cultured for Id,3d,5d is 11.56,12.02,11.9. The pH of Mg-4.0Zn-1.5Sr with laser surface processing and alkaline treatment is more stable. They are more suitable for the human body.(7) Through the MTT test and cell morphology analysis, The RGR values of Mg-4.0Zn-1.5Sr cultured for Id,3d,5d is 100%,108.8%,101.8%. The RGR values of Mg-4.0Zn-1.5Sr with laser surface processing and alkaline treatment cultured for 1d,3d,5d is 105.7%、106.0%、107.4%.the materials were approximately at level zero. Thecell activity of Mg-4.0Zn-1.5Sr alloy with laser surface processing and alkaline treatment improves slightly. |
PDF Full Text Request