多孔镁的微波烧结制备及改性研究

发布时间：2019-03-12 17:46

【摘要】：镁及镁合金具有高的比强度和比刚度,弹性模量和密度与人体硬组织接近和可降解性,是理想的硬组织替代材料。将多孔结构引入镁,更有利于血液和营养运输和传送,血管和肌肉长入。但是多孔结构也会降低材料的强度和耐蚀性。本论文采用微波烧结技术制备了多孔Mg,并对其进行了SiC颗粒增强(形成SiC/Mg复合材料)和微弧氧化表面改性研究。探讨了工艺参数和造孔剂对多孔Mg表面形貌、孔隙率、硬度、压缩性能、耐蚀性能以及降解性能的影响规律;研究了Si C颗粒含量以及粒径对多孔Mg的显微结构、相组成、压缩性能、降解性能以及摩擦性能的影响;研究了微弧氧化电参数对多孔Mg陶瓷膜显微结构和耐蚀性的影响。试验结果表明随着微波烧结温度的增加、保温时间的延长和压制压力的降低,多孔Mg的孔隙率增大,显微硬度下降。随着造孔剂含量的增加,多孔Mg的孔隙率随之增加,而造孔剂粒径的大小对多孔Mg孔隙率影响不大;随着孔隙率的增加,多孔Mg的压缩强度和弹性模量随之降低,腐蚀电流密度逐渐增加,极化电阻逐渐减小。随着多孔Mg孔径的增大,其压缩强度逐渐降低,弹性模量和耐蚀性变化不大;随着孔隙率的增加,浸泡时间的延长,多孔Mg在SBF溶液中的失重率增加,降解速率也增加,而SBF溶液的PH值随着浸泡时间的延长而增大,但孔隙率对PH的影响不大。SiC增强相的加入对多孔Mg的显微结构无明显影响,但多孔SiCp/镁基复合材料的压缩强度随着SiC含量的增加先增加后减小,10%时获得最大值,而弹性模量随着SiC含量的增加呈增加,其压缩强度和弹性模量较多孔Mg最大可提高了47.87%和57.32%;多孔SiCp/镁基复合材料的压缩强度随着SiC粒径的增大而增大,弹性模量随着SiC粒径的增大,先增大后减小;SiC含量对多孔Mg的耐蚀性影响不大;多孔Si Cp/镁基复合材料的摩擦系数、磨损体积和磨损率均随着Si C颗粒含量的增加而增大。微弧氧化处理未改变多孔Mg的固有多孔结构,经微弧氧化处理后,多孔Mg表面和孔内壁均形成了典型的微弧氧化粗糙多孔陶瓷层,其厚度在1.5~7.8μm。微弧氧化处理后的多孔Mg其耐蚀性较基体提高1个数量级以上,在SBF溶液中的降解速率和失重率也有所降低。
[Abstract]:Magnesium and magnesium alloys have high specific strength and specific stiffness, elastic modulus and density are close to and degradable to human hard tissue, so magnesium alloy is an ideal substitute material for hard tissue. Introduction of porous structure into magnesium, more conducive to blood and nutrition transport and transport, blood vessels and muscle growth. However, porous structure can also reduce the strength and corrosion resistance of the material. In this paper, porous Mg, was prepared by microwave sintering, and SiC particle reinforced (formed SiC/Mg composite) and surface modification by micro-arc oxidation were studied. The effects of process parameters and pore-forming agents on the surface morphology, porosity, hardness, compression property, corrosion resistance and degradation performance of porous Mg were discussed. The effects of Si-C content and particle size on the microstructure, phase composition, compressive properties, degradation properties and friction properties of porous Mg ceramic films were studied, and the effects of micro-arc oxidation electrical parameters on the microstructure and corrosion resistance of porous Mg ceramic films were studied. The experimental results show that the porosity of porous Mg increases and the microhardness decreases with the increase of microwave sintering temperature, the prolongation of holding time and the decrease of pressing pressure. With the increase of pore-forming agent content, the porosity of porous Mg increases, but the size of pore-forming agent has little effect on the porosity of porous Mg. With the increase of porosity, the compressive strength and elastic modulus of porous Mg decrease, the corrosion current density increases and the polarization resistance decreases. With the increase of pore size of porous Mg, the compressive strength decreased gradually, and the elastic modulus and corrosion resistance did not change much. With the increase of porosity and immersion time, the weight loss rate and degradation rate of porous Mg in SBF solution increased, while the PH value of SBF solution increased with the prolongation of immersion time. However, the porosity has little effect on PH. The addition of sic reinforcement has no obvious effect on the microstructure of porous Mg, but the compressive strength of porous SiCp/ magnesium matrix composites increases first and then decreases with the increase of SiC content, and reaches the maximum value at 10%. With the increase of SiC content, the compressive strength and modulus of elasticity increased by 47.87% and 57.32%, respectively, compared with porous Mg. The compressive strength of porous SiCp/ magnesium matrix composites increases with the increase of SiC particle size, and the elastic modulus increases first and then decreases with the increase of SiC particle size, while the SiC content has little effect on the corrosion resistance of porous Mg. The friction coefficient, wear volume and wear rate of porous Si Cp/ magnesium matrix composites increase with the increase of Si-C particle content. Micro-arc oxidation treatment did not change the inherent porous structure of porous Mg. After micro-arc oxidation treatment, both the surface and inner wall of porous Mg formed a typical micro-arc oxidation rough porous ceramic layer, the thickness of which was 1.5 ~ 7.8 渭 m. The corrosion resistance of porous Mg treated by micro-arc oxidation is more than one order of magnitude higher than that of matrix, and the degradation rate and weight loss rate in SBF solution are also decreased.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.4;TB333

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