To investigate the influence of oxygen content in a physiological liquid environment on the corrosion behavior of biomedical zinc-based alloys,a simulated bodily fluid environment with varying dissolved oxygen was est...To investigate the influence of oxygen content in a physiological liquid environment on the corrosion behavior of biomedical zinc-based alloys,a simulated bodily fluid environment with varying dissolved oxygen was established in vitro using external oxygen supply equipment.The influence of dissolved oxygen concentration on the corrosion behavior of pure Zn and Zn−Cu alloys was studied with scanning electron microscopy,energy dispersive spectroscopy,Fourier transform infrared spectrometry,and electrochemical analysis.Due to oxygen absorption corrosion,the increase in dissolved oxygen concentration increases the pH value of the solution and promotes the accumulation of corrosion product layer.Compared with the environment without additional oxygen supply,the corrosion rate of the sample under the continuous oxygen supply condition is increased by one order of magnitude.Because the Zn−Cu alloy has micro-galvanic corrosion,its corrosion rate is about 1.5 times that of pure zinc under different dissolved oxygen conditions.展开更多
This study reports on the effect of the addition of Glycine to Hank’s solution on the in-vitro corrosion behavior of AZ31 magnesium(Mg)alloy at 37℃and a pH of 7.4 studied by using potentiodynamic polarization(PDP),h...This study reports on the effect of the addition of Glycine to Hank’s solution on the in-vitro corrosion behavior of AZ31 magnesium(Mg)alloy at 37℃and a pH of 7.4 studied by using potentiodynamic polarization(PDP),hydrogen collecting techniques and electrochemical impedance spectroscopy(EIS)in combination with surface characterization techniques such as optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy analysis(XPS).The results reveal that adsorption of glycine initially subdues the dissolution of AZ31 Mg alloy while in long run it enhances the dissolution of the alloy due to the commencement of the chelation effect of glycine with Ca^(2+) released from hydroxyapatite.The chelation of glycine with Ca^(2+) induces the formation of cracks in the surface film which further promotes the dissolution of AZ31 Mg alloy thereby forming a porous corrosion products layer on the surface of the alloy.As a result,both the continuous dissolution of AZ31 magnesium alloy and the hydrogen evolution rate(HER)are enhanced with increasing the immersion time in Hank’s solution.展开更多
An Mg-Zn-Mn-Ca alloy with high Zn content was fabricated by vacuum melting. The as-cast microstructure was investigated using XRD, SEM and EDS. It was shown that the alloy was composed of α-Mg, strip-like Ca2Mg6Zn3 a...An Mg-Zn-Mn-Ca alloy with high Zn content was fabricated by vacuum melting. The as-cast microstructure was investigated using XRD, SEM and EDS. It was shown that the alloy was composed of α-Mg, strip-like Ca2Mg6Zn3 and a few Mn- containing phases. Most of the Ca2Mg6Zn3 phase was distributed at grain boundaries while Mn-containing particles were deposited within grains. The as-cast samples were immersed in a Hank＇s balanced salt solution （HBSS） up to 24 h. The corroded surface morphology and cross-section microstructure were analyzed after different time of immersion so as to understand the corrosion behavior of the alloy. During immersion in the HBSS, the alloy corroded homogeneously at the very beginning and then localized corrosion occurred. The secondary phases protruded on the surface due to the dissolution of α-Mg, suggesting micro- galvanic corrosion occurred with secondary phases acting as the cathode and ct-Mg as the anode. Micro-cracks were formed at the interfaces between Ca2Mg6Zn3 and α-Mg, indicating an undermining tendency of the secondary phases.展开更多
The degradation behavior of biodegradable Mg alloys has become a research hotspot in the fields about biodegradable metallic materials.While the most of the related publications mainly focused on the degradation rate ...The degradation behavior of biodegradable Mg alloys has become a research hotspot in the fields about biodegradable metallic materials.While the most of the related publications mainly focused on the degradation rate of Mg-based materials,but rare to care about the changes of their mechanical properties during the immersion period,which can significantly affect their service performance.The link between residual strength and Mg degradation is not appreciated enough.In this work,a series media were constructed based on Hanks’solution,the effects of inorganic ions on the degradation rate and mechanical integrity of Mg-Zn-Y-Nd alloy were investigated.The results indicated that the degradation behavior of Mg alloy was mainly controlled by degradation products and there is no direct correspondence between the degradation rate change and mechanical integrity of Mg alloy.The relevant findings are beneficial for selecting the monitoring index in Mg corrosion tests and evaluating the service reliability of Mg alloys for biomedical applications.展开更多
Hydroxyapatite （HA, Ca10（PO4）6（OH）2） coating was fabricated on pure Ti （TA2） by laser cladding technology. The phase structure, microstructure, microhardness and electrochemical behavior of the laser cladded H...Hydroxyapatite （HA, Ca10（PO4）6（OH）2） coating was fabricated on pure Ti （TA2） by laser cladding technology. The phase structure, microstructure, microhardness and electrochemical behavior of the laser cladded HA coating in artificial body fluid were investigated. The results show that the HA coating is mainly composed of highly crystallized HA. A transitional layer between HA coating and Ti substrate is formed. Microhardness measurement shows the gradually increasing of microhardness from 150 HV at TA2 substrate to 600 HV at transitional layer, and followed by a decreasing to 400 HV at HA coated layer. Electrochemical corrosion tests show that the HA coating has higher open circuit potential , lower corrosion current density and corrosion rate in comparison to the TA2 substrate.展开更多
The effects of alloying elements of Ca/Sn on corrosion behaviors of the as-cast Mg-4Zn-0.2Mn alloy were investigated by immersion tests and electrochemical methods.The results indicated that the average corrosion rate...The effects of alloying elements of Ca/Sn on corrosion behaviors of the as-cast Mg-4Zn-0.2Mn alloy were investigated by immersion tests and electrochemical methods.The results indicated that the average corrosion rate value of the Mg-4Zn-0.2Mn-Ca alloy was∼0.31 mm/year in Hank’s physiological solution for 40 days,and corrosion resistance increased for the specimens containing Ca element rather than that containing Sn because of the higher breakdown potential value,lower current density and deactivated corrosion rate,which was ascribed to a formation of the uniformly distributed Mg-Zn-Ca ternary phase.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52171236,51971062,52231005)Open Research Fund of Jiangsu Key Laboratory for Advanced Metallic Materials,Southeast University,China(No.AMM2024A01)+3 种基金Suzhou Science and Technology Project,China(Nos.SJC2023005,SZS2023023)City University of Hong Kong Donation Research Grant,China(No.DON-RMG 9229021)City University of Hong Kong Strategic Research Grant,China(No.SRG 7005505)City University of Hong Kong Donation Grant,China(No.9220061)。
文摘To investigate the influence of oxygen content in a physiological liquid environment on the corrosion behavior of biomedical zinc-based alloys,a simulated bodily fluid environment with varying dissolved oxygen was established in vitro using external oxygen supply equipment.The influence of dissolved oxygen concentration on the corrosion behavior of pure Zn and Zn−Cu alloys was studied with scanning electron microscopy,energy dispersive spectroscopy,Fourier transform infrared spectrometry,and electrochemical analysis.Due to oxygen absorption corrosion,the increase in dissolved oxygen concentration increases the pH value of the solution and promotes the accumulation of corrosion product layer.Compared with the environment without additional oxygen supply,the corrosion rate of the sample under the continuous oxygen supply condition is increased by one order of magnitude.Because the Zn−Cu alloy has micro-galvanic corrosion,its corrosion rate is about 1.5 times that of pure zinc under different dissolved oxygen conditions.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51701221 and 51801219)the National Key Research and Development Program of China(No.2017YFB0702302)。
文摘This study reports on the effect of the addition of Glycine to Hank’s solution on the in-vitro corrosion behavior of AZ31 magnesium(Mg)alloy at 37℃and a pH of 7.4 studied by using potentiodynamic polarization(PDP),hydrogen collecting techniques and electrochemical impedance spectroscopy(EIS)in combination with surface characterization techniques such as optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy analysis(XPS).The results reveal that adsorption of glycine initially subdues the dissolution of AZ31 Mg alloy while in long run it enhances the dissolution of the alloy due to the commencement of the chelation effect of glycine with Ca^(2+) released from hydroxyapatite.The chelation of glycine with Ca^(2+) induces the formation of cracks in the surface film which further promotes the dissolution of AZ31 Mg alloy thereby forming a porous corrosion products layer on the surface of the alloy.As a result,both the continuous dissolution of AZ31 magnesium alloy and the hydrogen evolution rate(HER)are enhanced with increasing the immersion time in Hank’s solution.
文摘An Mg-Zn-Mn-Ca alloy with high Zn content was fabricated by vacuum melting. The as-cast microstructure was investigated using XRD, SEM and EDS. It was shown that the alloy was composed of α-Mg, strip-like Ca2Mg6Zn3 and a few Mn- containing phases. Most of the Ca2Mg6Zn3 phase was distributed at grain boundaries while Mn-containing particles were deposited within grains. The as-cast samples were immersed in a Hank＇s balanced salt solution （HBSS） up to 24 h. The corroded surface morphology and cross-section microstructure were analyzed after different time of immersion so as to understand the corrosion behavior of the alloy. During immersion in the HBSS, the alloy corroded homogeneously at the very beginning and then localized corrosion occurred. The secondary phases protruded on the surface due to the dissolution of α-Mg, suggesting micro- galvanic corrosion occurred with secondary phases acting as the cathode and ct-Mg as the anode. Micro-cracks were formed at the interfaces between Ca2Mg6Zn3 and α-Mg, indicating an undermining tendency of the secondary phases.
基金support from the Na-tional Key Research and Development Program of China(2021YFC2400703)the Key Projects of the Joint Fund of the National Natural Science Foundation of China(U1804251)support from Natural Science Foundation of Henan Provincial(222300420309).
文摘The degradation behavior of biodegradable Mg alloys has become a research hotspot in the fields about biodegradable metallic materials.While the most of the related publications mainly focused on the degradation rate of Mg-based materials,but rare to care about the changes of their mechanical properties during the immersion period,which can significantly affect their service performance.The link between residual strength and Mg degradation is not appreciated enough.In this work,a series media were constructed based on Hanks’solution,the effects of inorganic ions on the degradation rate and mechanical integrity of Mg-Zn-Y-Nd alloy were investigated.The results indicated that the degradation behavior of Mg alloy was mainly controlled by degradation products and there is no direct correspondence between the degradation rate change and mechanical integrity of Mg alloy.The relevant findings are beneficial for selecting the monitoring index in Mg corrosion tests and evaluating the service reliability of Mg alloys for biomedical applications.
基金Funded by the National Natural Science Foundation of China(No. 50971102)Shannxi Province "13115" Key Science and Technology Project (No. 2010ZDKG-51)
文摘Hydroxyapatite （HA, Ca10（PO4）6（OH）2） coating was fabricated on pure Ti （TA2） by laser cladding technology. The phase structure, microstructure, microhardness and electrochemical behavior of the laser cladded HA coating in artificial body fluid were investigated. The results show that the HA coating is mainly composed of highly crystallized HA. A transitional layer between HA coating and Ti substrate is formed. Microhardness measurement shows the gradually increasing of microhardness from 150 HV at TA2 substrate to 600 HV at transitional layer, and followed by a decreasing to 400 HV at HA coated layer. Electrochemical corrosion tests show that the HA coating has higher open circuit potential , lower corrosion current density and corrosion rate in comparison to the TA2 substrate.
基金supported by National Key Research and Development Program of China(2016YFB0301101,2016YFB0301001)Beijing Natural Science Foundation(2172013).
文摘The effects of alloying elements of Ca/Sn on corrosion behaviors of the as-cast Mg-4Zn-0.2Mn alloy were investigated by immersion tests and electrochemical methods.The results indicated that the average corrosion rate value of the Mg-4Zn-0.2Mn-Ca alloy was∼0.31 mm/year in Hank’s physiological solution for 40 days,and corrosion resistance increased for the specimens containing Ca element rather than that containing Sn because of the higher breakdown potential value,lower current density and deactivated corrosion rate,which was ascribed to a formation of the uniformly distributed Mg-Zn-Ca ternary phase.
