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造孔剂对医用多孔Ti/16Mg复合材料组织性能的影响

Effects of pore-forming agents on microstructure and properties of biomedical porous Ti/16Mg composites

  • 摘要: 采用粉末冶金工艺结合微波烧结法制备了弹性模量接近于人体骨骼、强度符合人体植入物要求的医用多孔Ti/16Mg复合材料。通过扫描电镜、X射线衍射、金相显微镜、压缩试验以及耐腐蚀性测试等手段研究了造孔剂NH4HCO3粒径及添加量(质量分数)对复合材料的微观组织、力学性能和耐腐蚀性能的影响。结果表明:NH4HCO3对多孔Ti/16Mg复合材料的物相组成没有显著影响,试样孔隙随着NH4HCO3粒径的增大而增大,随着NH4HCO3添加量增加,试样孔隙率由16.64%增加到33.09%。当NH4HCO3粒径为165~198 μm、质量分数为18%时,多孔Ti/16Mg试样的弹性模量为6.49 GPa、抗压强度为115 MPa,满足人体植入物的力学性能要求。NH4HCO3粒径对复合材料的耐腐蚀性影响不大,在相同粒径条件下,随NH4HCO3质量分数由0增加至24%,复合材料的耐腐蚀性能略有下降,极化电阻由574.528 Ω·cm‒2下降到139.236 Ω·cm‒2

     

    Abstract: The biomedical porous Ti/16Mg composite materials with the elastic modulus close to that of human bone and the strength meeting the requirements of human implants were prepared by powder metallurgy combined with microwave sintering method in this paper. The effects of particle size and addition amount (mass fraction) of NH4HCO3 pore-forming agents on the microstructure, mechanical properties, and corrosion resistance of the composites were investigated by scanning electron microscopy, X-ray diffraction, metallography, compression test, and corrosion resistance test. The results show that NH4HCO3 has no significant effect on the phase composition of porous Ti/16Mg composites. The pore size increases with the increase of NH4HCO3 particle size, and the porosity increases from 16.64% to 33.09% with the increase of NH4HCO3 mass fraction. When the particle size of NH4HCO3 is 165~198 μm and the mass fraction is 18%, the elastic modulus of the porous Ti/16Mg composites is 6.49 GPa and the compressive strength is 115 MPa, which can meet the mechanical property requirements of human implants. Particle size of NH4HCO3 has little effect on the corrosion resistance of the porous Ti/16Mg composites. With the same particle size, the corrosion resistance of the porous Ti/16Mg composites decreases slightly and the polarization resistance decreases from 574.528Ω·cm‒2 to 139.236Ω·cm‒2 with the mass fraction of NH4HCO3 increasing from 0 to 24%.

     

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