摘要
Biodegradable Mg-xB i(x = 3, 6 and 9wt.%) alloys were fabricated by ingot casting, and the change of corrosion behavior of the alloys in the Hank's solution was analyzed with respect to the microstructure using optical micrograph(OM), X-ray diffraction(XRD), scanning electron microscope(SEM) equipped with an energy dispersive X-ray spectrometer(EDS), electrochemical and immersion tests. The results show that the microstructures of the as-cast Mg-Bi alloys mainly consisted of dendritic α-Mg grains and Mg3Bi2 phase in common, with the secondary dendrite arm spacing(SDAS) decreasing significantly from 41.2 μm to 25.4 μm and the fraction of Mg3Bi2 increasing from 3.1% to 10.7%. Furthermore, the corrosion rate increasing from 1.32 mm·a-1 to 8.07 mm·a-1 as the Bi content was increased from 3wt.% to 9wt.%. The reduced corrosion resistance was mainly ascribed to the increasing fraction of the second phase particles, which bring positive effects on the development of pitting.
Biodegradable Mg-xB i（x = 3, 6 and 9wt.%） alloys were fabricated by ingot casting, and the change of corrosion behavior of the alloys in the Hank＇s solution was analyzed with respect to the microstructure using optical micrograph（OM）, X-ray diffraction（XRD）, scanning electron microscope（SEM） equipped with an energy dispersive X-ray spectrometer（EDS）, electrochemical and immersion tests. The results show that the microstructures of the as-cast Mg-Bi alloys mainly consisted of dendritic α-Mg grains and Mg3Bi2 phase in common, with the secondary dendrite arm spacing（SDAS） decreasing significantly from 41.2 μm to 25.4 μm and the fraction of Mg3Bi2 increasing from 3.1% to 10.7%. Furthermore, the corrosion rate increasing from 1.32 mm·a-1 to 8.07 mm·a-1 as the Bi content was increased from 3wt.% to 9wt.%. The reduced corrosion resistance was mainly ascribed to the increasing fraction of the second phase particles, which bring positive effects on the development of pitting.
基金
supported by the National Natural Science Foundation of China(Grant no.51404166)
Shanxi Province Science Foundation for Youths(2013021013-4)
the Research Project Supported by Shanxi Scholarship Council of China(2014-023)
the Technological Innovation Programs of Higher Education Institutions in Shanxi(Grant no.2014120)
the Advanced Programs of Department of Human Resources and Social Security of Shanxi Province for Returned Scholars(2013101)
