Biodegradable magnesium(Mg)alloys have received increased attention as temporary medical implants due to their mechanical properties and density,similar to natural bone.However,the fast corrosion of Mg alloys in a phy...Biodegradable magnesium(Mg)alloys have received increased attention as temporary medical implants due to their mechanical properties and density,similar to natural bone.However,the fast corrosion of Mg alloys in a physiological condition limits their wide applications.Hence,hydroxyapatite(HAp)coatings on Mg alloys have attracted much attention to address this corrosion issue and enhance the surface functionalities.In this paper,we present a review of HAp coating strategies on Mg alloys,including the sol-gel method,hydrothermal treatment,biomimetic coating,electrochemical deposition,electrophoretic deposition,and plasma electrolytic oxidation technique,and their recent progress to enhance the surface characteristics of Mg alloys.This review focused on aspects of coating morphology,hybrid formulations,and how they influence corrosion behavior as well as in vitro and in vivo performance.Moreover,we have discussed the future prospects of HAp-coating strategies,emphasizing on multifunctional,hybrid,and smart coatings for next-generation implant materials.展开更多
Superparamgnetic Fe_3O_4 and RE:Fe_3O_4(RE=Dy,Nd,La)nanoparticles with an average crystallite size in the range of 15–24 nm,were synthesized by co-precipitation method.The samples were characterized using X-ray diffr...Superparamgnetic Fe_3O_4 and RE:Fe_3O_4(RE=Dy,Nd,La)nanoparticles with an average crystallite size in the range of 15–24 nm,were synthesized by co-precipitation method.The samples were characterized using X-ray diffraction(XRD),scanning electron microscopy(SEM),vibrating sample magnetometer(VSM),UV–Vis spectroscopy,LCR bridge,and two-probe technique.X-ray diffraction patterns of all the investigated samples reveal the typical phase of magnetite structure,with a small contribution of orthoferrite(NdFeO_3)as a secondary phase in Nd:Fe_3O_4 sample.The saturation magnetization(M_s)of the samples has values in the range from 41.8 to 52.3 emu/g,and decreases with RE ion doping depending on the ionic radius.Negligible values of the coercivity H_c and remanenceM_r,indicate the superparamagnetic nature of the investigated samples.The calculated values of indirect optical band gap of Fe_3O_4 and RE:Fe_3O_4 nanoparticles are in the range of0.9–1.25 eV.The dielectric constant of the samples decreases,while their activation energy increases with the increasing of ionic radii of dopants.展开更多
基金the Deanship of Research and Graduate Studies at King Khalid University for funding this work through Small Group Research Project under grant number RGP1/34/46 (RGP1/34/46)
文摘Biodegradable magnesium(Mg)alloys have received increased attention as temporary medical implants due to their mechanical properties and density,similar to natural bone.However,the fast corrosion of Mg alloys in a physiological condition limits their wide applications.Hence,hydroxyapatite(HAp)coatings on Mg alloys have attracted much attention to address this corrosion issue and enhance the surface functionalities.In this paper,we present a review of HAp coating strategies on Mg alloys,including the sol-gel method,hydrothermal treatment,biomimetic coating,electrochemical deposition,electrophoretic deposition,and plasma electrolytic oxidation technique,and their recent progress to enhance the surface characteristics of Mg alloys.This review focused on aspects of coating morphology,hybrid formulations,and how they influence corrosion behavior as well as in vitro and in vivo performance.Moreover,we have discussed the future prospects of HAp-coating strategies,emphasizing on multifunctional,hybrid,and smart coatings for next-generation implant materials.
基金the Deanship of Scientific Research at King Khalid University for funding this work through General Research Project under grant number G.R.P-310-38
文摘Superparamgnetic Fe_3O_4 and RE:Fe_3O_4(RE=Dy,Nd,La)nanoparticles with an average crystallite size in the range of 15–24 nm,were synthesized by co-precipitation method.The samples were characterized using X-ray diffraction(XRD),scanning electron microscopy(SEM),vibrating sample magnetometer(VSM),UV–Vis spectroscopy,LCR bridge,and two-probe technique.X-ray diffraction patterns of all the investigated samples reveal the typical phase of magnetite structure,with a small contribution of orthoferrite(NdFeO_3)as a secondary phase in Nd:Fe_3O_4 sample.The saturation magnetization(M_s)of the samples has values in the range from 41.8 to 52.3 emu/g,and decreases with RE ion doping depending on the ionic radius.Negligible values of the coercivity H_c and remanenceM_r,indicate the superparamagnetic nature of the investigated samples.The calculated values of indirect optical band gap of Fe_3O_4 and RE:Fe_3O_4 nanoparticles are in the range of0.9–1.25 eV.The dielectric constant of the samples decreases,while their activation energy increases with the increasing of ionic radii of dopants.
