流变铸造Mg-Ag合金骨植入材料局部腐蚀机理研究

The incidence of bone fractures has been increasing for decades, which promotes a bigger sized bone implant material market accordingly. As a biodegradable material which needs no extra surgery for removal, magnesium alloys exhibits its potential to replace the widely used permanent implant materials, but the localized corrosion behaviors inhibit their medical application as implants. Some studies as well as the applicant’s previous study showed that localized corrosion process of magnesium alloys could be slowed by semi-solid processing methods. However, the mechanism of this effect especially the mechanism in bone tissue circumstance has not been thoroughly revealed. Clarification of this scientific issue could provide guidelines for studies on processing and corrosion properties of magnesium alloy bone implant materials..Therefore, the applicant hereby propose to study the mechanism of localized corrosion of antibacterial Mg-Ag alloys as bone implants, which were originally designed for bone implantation by the applicant. In vitro and in vivo corrosion tests will be carried out to identify the influences of microstructure on distribution of corrosion potential and absorbance of organic compounds, as well as the effects of distribution of alloy elements on pitting corrosion. Based on the revealed localized corrosion mechanism, the mathematical model and according control technics to localized corrosion could be established. Finally, the core objective of this project could be achieved, to provide guidelines for the manufacture and clinical application of magnesium alloy bone implant materials.

骨折发病率的逐年增高促使骨科植入材料市场需求不断增长，镁合金作为骨科植入材料可以在人体内降解从而避免二次手术，逐步展现出替代传统植入材料的潜力，但其在生物体内的局部腐蚀行为限制了临床应用。已有报道和申请人的前期研究结果都表明，经流变铸造成形的镁合金局部腐蚀敏感性显著降低，但其作用机制特别是在生物腐蚀介质中的局部腐蚀机理尚未明确。该科学问题的研究对医用镁合金骨植入材料的加工和腐蚀研究具有指导意义。. 为此本项目提出以申请人前期研发的Mg-Ag抗菌合金为研究对象，研究其流变铸造组织在骨植入环境中的局部腐蚀机理。项目拟进行体外腐蚀实验和动物骨组织植入实验，研究其组织特征对合金表面腐蚀电位分布和有机物吸附的影响机理，以及溶质分布对点蚀的作用机制。最终建立流变铸造镁合金材料的局部腐蚀模型及其控制方法，为镁合金骨植入材料的制备和临床应用提供指导。

.　骨科植入材料市场需求随着骨折发病率的逐年增高而不断增长，可降解镁合金骨科植入材料因为其可降解的特性可以避免二次手术，逐步展现出替代传统植入材料的潜力，但其在生物体内的局部腐蚀行为限制了临床应用。已有报道和申请人的前期研究结果都表明，经流变铸造成型的镁合金局部腐蚀速率显著降低，但其作用机制特别是在生物腐蚀介质中的局部腐蚀机理尚未明确。该项目的研究将以这个现象入手，研究流变凝固组织的局部腐蚀特性，进而设计制备具有较好耐蚀性能的镁合金骨植入材料。.　.　为此本项目以申请人前期研发的Mg-Ag抗菌合金为研究对象，研究其流变铸造组织在骨植入环境中的局部腐蚀机理。项目进行了体外腐蚀实验和动物骨组织植入实验，研究了其组织特征对合金表面腐蚀电位分布和有机物吸附的影响机理，以及溶质分布对点蚀的作用机制。通过项目研究，解决了两个关键科学问题：①揭示了流变铸造Mg-Ag合金的析出相的形态和分布特征对合金表面电化学参数的影响规律，以及对局部腐蚀初始阶段动力学的影响；②阐明了合金组织的溶质分布对有机物吸附程度以及对点蚀敏感性的作用机制。项目最终系统解释了流变铸造Mg-Ag合金在骨植入环境下的局部腐蚀机理，建立了通过流变铸造手段提高Mg-Ag合金在骨植入环境中抗局部腐蚀性能的方法。项目研究成果可为镁合金骨植入材料的制备和临床应用提供指导。