HA(β-TCP)/Mg-Zn-Ca复合材料的腐蚀特性研究

Corrosion Properties of Composite Materials HA(β- TCP)/Mg-Zn-Ca

本实验主要研究HA及β-TCP添加对Mg-Zn-Ca合金组织及模拟体液环境下的腐蚀特性影响。采用剪切搅拌铸造方式制备了2HA(2β-TCP)/Mg-3Zn-0.5Ca复合材料,并对两种复合材料的显微组织及腐蚀特性进行了测试与对比分析。研究结果表明:添加β-TCP的复合材料相对于添加HA的复合材料晶粒细化程度高,原因为β-TCP与镁的错配度小于HA与镁的错配度,使β-TCP成为更有效的形核基底;添加β-TCP复合材料的腐蚀电位稍高于添加HA复合材料的腐蚀电位;在模拟体液的浸泡实验中,添加β-TCP的镁基复合材料在前期的腐蚀速率低于同含量HA的镁基复合材料,但随浸泡时间的延长,添加HA复合材料形成的保护层比添加β-TCP复合材料的更均匀致密,复合材料的失重更低。

The influences of HA and β-TCP addition on microstructure and corrosion behavior of Mg-Zn-Ca alloys were studied in simulated body fluid. 2HA(2β-TCP)/Mg-3Zn-0.5Ca composites were prepared by means of shear mixing casting, and microstructure and corrosion behavior properties of the two composites were tested and comparatively analyzed. As a results, the grain size of β-TCP reinforced composites is finer than that of HA reinforced composites because the misfit degree between β-TCP and magnesium is lower than that of HA and magnesium. The corrosion potential of β-TCP reinforced composites is slightly higher than that of HA reinforced composites. Corrosion rate of β-TCP reinforced composites is lower than that of HA reinforced composites in the early immersion period; however, with the increasing time of immersion, 2HA /Mg-3Zn-0.5Ca composites exhibit more uniform and dense protective layer than 2β-TCP/Mg-3Zn-0.5Ca composites, which results in that 2HA /Mg-3Zn-0.5Ca has lower mass loss rate.