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对可生物降解二元Mg-6Zn合金进行固溶处理,来评价获得的显微组织变化对合金降解速率的影响及其相关机理。在350°C条件下固溶处理6~48 h。采用光学显微镜、扫描电镜、能量色散X射线光谱仪和X射线衍射仪分析铸态和固溶处理后试样。在37°C的模拟体液中进行浸泡和电化学测试,评价其抗腐蚀性。为保证腐蚀测试的结果,对p H值进行测试。结果发现,大于24 h的固溶处理,金属间化合物相溶解于基体中,并产生了近单晶相组织。金属间化合物相的减少导致阴极区/阳极区比减小且腐蚀率降低。电化学和失重测试结果表明,延长固溶处理时间可提高合金的抗腐蚀性。经350°C固溶处理24 h后,铸态合金的抗腐蚀性提高了60%以上。另外,逐渐减少的金属间化合物相和伴随的低p H值上升,降低了腐蚀速率。对于Mg-Zn合金作为生物可降解移植材料的应用,固溶处理是一种可以提高腐蚀性的工艺。
The biodegradable binary Mg-6Zn alloy was subjected to solution treatment to evaluate the effect of the obtained microstructure changes on the degradation rate of the alloy and the related mechanisms. Solution treatment at 350 ° C for 6 ~ 48 h. The as-cast and solution-treated specimens were analyzed by light microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffractometry. Immersion and electrochemical tests were performed in simulated body fluids at 37 ° C to evaluate their corrosion resistance. To assure the result of the corrosion test, the p H value is tested. The results show that, after more than 24 h of solution treatment, the intermetallics dissolve in the matrix and produce near-single crystal phase structure. The reduction of the intermetallic phase results in a decrease of cathode / anode area ratio and a decrease of corrosion rate. Electrochemical and weight loss test results show that prolong the solution treatment time can improve the corrosion resistance of the alloy. After 350 ° C solution treatment for 24 h, the corrosion resistance of cast alloy increased by more than 60%. In addition, the decreasing intermetallic phase and accompanying low p H values increase the corrosion rate. For Mg-Zn alloys as a biodegradable graft material, solution treatment is a process that increases corrosion.