Construction of Fe/Ag galvanic couple by mechanochemical in-situ reduced Ag to accelerate the degradation of Fe-based implant

Orthopedic applications of Fe have been hindered by the insufficient degradation rate. Alloying with noble elements (such as Ag, Au, and Pt) to generate galvanic couples is a feasible approach. However, the direct preparation of homogenous alloys by mechanical alloying or metallurgy is difficult bec...

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Bibliographic Details
Published in:Science China. Technological sciences 2023-10, Vol.66 (10), p.2824-2836
Main Authors: Yang, WenJing, Song, Hao, Zhao, ZhengYu, Shuai, CiJun, Pan, Hao
Format: Article
Language:English
Subjects:
Acceleration
Alloy powders
Alloying elements
Biocompatibility
Chemical reduction
Cooling rate
Corrosion
Corrosion currents
Corrosion rate
Degradation
Engineering
Laser beam melting
Mechanical alloying
Orthopedics
Phase distribution
Silver
Transplants & implants
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Summary:Orthopedic applications of Fe have been hindered by the insufficient degradation rate. Alloying with noble elements (such as Ag, Au, and Pt) to generate galvanic couples is a feasible approach. However, the direct preparation of homogenous alloys by mechanical alloying or metallurgy is difficult because of the differences in strength, density, and toughness. In this study, Ag 2 O was selected as the precursor phase for incorporation into Fe to achieve a homogeneous distribution of Ag, which was then reduced in situ to Ag via a mechanochemical reduction reaction during mechanical alloying. The composite powders were printed as implants by selective laser melting, where a fast cooling rate contributed to the retention of the phase distribution of the obtained powder. The electrochemical tests showed that the Fe-Ag 2 O implant had a high corrosion current density (21.88 ± 0.12 µA/cm 2 ) and instantaneous corrosion rate (0.23 ± 0.05 mm/year). Moreover, the implant exhibited a faster degradation rate (0.22 mm/year) than Fe (0.15 mm/year) and Fe-Ag (0.21 mm/year) after immersion for 28 d. The acceleration mechanism of the implant could be attributed to the uniformly distributed Ag particles triggering many galvanic couples with the Fe grains, which was confirmed by the observation of the corrosion surface. In addition, the composite implants exhibited good biocompatibility and antibacterial properties.
ISSN:1674-7321
1869-1900
DOI:10.1007/s11431-022-2412-y