Pure Mg boasting a relatively small corrosion rate is a potential biodegradable metal material for implants.However,its degradation behavior in the complex physiological environment is still a lack of understanding.In...Pure Mg boasting a relatively small corrosion rate is a potential biodegradable metal material for implants.However,its degradation behavior in the complex physiological environment is still a lack of understanding.In this work,we investigated the effect of corrosion product film layers on the degradation behavior of pure Mg in physiological environments.Pure Mg shows a faster corrosion rate in simulated body fluid(SBF)compared to NaCl solution.Hydrogen evolution experiments indicate that the degradation rate of pure Mg in SBF decreases rapidly within the first 12 h but stabilizes afterward.The rapid deposition of low-solubility calcium phosphate on the pure Mg in SBF provides protection to the substrate,resulting in a gradual decrease in the degradation rates.Consequently,the corrosion product film of pure Mg formed in SBF exhibits a layered structure,with the upper layer consisting of dense Ca_(3)(PO_(4))_(2)/Mg_(3)(PO_(4))_(2) and the lower layer consisting of Mg(OH)_(2)/MgO.Electrochemical impedance spectroscopy(EIS)shows that the resistance of the corrosion product film increases over time,indicating gradual strengthening of the corrosion resistance.The 4-week degradation results in the femoral marrow cavity of mice are consistent with the result in SBF in vitro.展开更多
Magnesium(Mg)alloys have excellent biocompatibility and biodegradability,making them promising for clinical applications.However,their rapid degradation compared to bone healing limits their effectiveness.In this stud...Magnesium(Mg)alloys have excellent biocompatibility and biodegradability,making them promising for clinical applications.However,their rapid degradation compared to bone healing limits their effectiveness.In this study,low-intensity pulsed ultrasound(LIPUS),widely used clinically to promote bone healing,was combined with Mg alloy scaffolds to evaluate scaffold degradation under dynamic conditions,in vitro using Hanks’balanced salt solution+BSA solution and in vivo in the femoral condyles of male SD rats.Results showed that LIPUS accelerated the initial degradation of the scaffold in both in vivo and in vitro experiments.In vitro,LIPUS increased BSA adsorption on scaffold surfaces,with adsorption increasing alongside LIPUS intensity.Limited BSA replenishment led to a thin organic-inorganic film that provided weak resistance to corrosive ions,accelerating degradation.Cavitation induced by LIPUS caused microbubble collapse,detaching Ca-P salts from scaffold surfaces.In vivo,LIPUS enhanced cell membrane permeability and activity,promoting the secretion of substances that formed a thicker organic-inorganic composite layer.Continuous material replenishment in the in vivo environment ensured the protective effect of this layer against corrosive ions,while embedded Ca-P salts were less likely to detach.In addition,LIPUS promotes bone modification.These findings highlight the potential of combining LIPUS with Mg alloys to regulate scaffold degradation,offering innovative strategies for clinical bone repair.展开更多
Zinc(Zn)-based materials show broad application prospects for bone repair due to their biodegradability and good biocompatibility.In particular,Zn metal foam has unique interconnected pore structure that facilitates i...Zinc(Zn)-based materials show broad application prospects for bone repair due to their biodegradability and good biocompatibility.In particular,Zn metal foam has unique interconnected pore structure that facilitates inward growth of new bone tissue,making it ideal candidates for orthopedic implants.However,pure Zn metal foam shows poor mechanical property,high degradation rate,and unsatisfactory osteogenic activity.Herein,Zinc-manganese(Zn-Mn)alloy foams were electrodeposited in Zn and Mn-containing electrolytes to overcome the concerns.The results showed that Mn could be incorporated into the foams in the form of MnZn_(13).Zn-Mn alloy foams showed better mechanical property and osteogenic activity as well as moderate degradation rate when compared with pure Zn metal foam.In addition,these properties could also be regulated by preparation process.The peak stress and osteogenic activity increased with deposition current(0.3‒0.5 A)and electrolyte pH(3‒5),but decreased with electrolyte temperature(20‒40℃),while the degradation rate exhibited opposite tendency,which suggests high deposition current and electrolyte pH and low electrolyte temperature can fabricate Zn-Mn alloy foam with favorable mechanical property,moderate degradation rate,and osteogenic activity.These findings provide a valuable reference for the design and fabrication of novel Zn-based biodegradable materials.展开更多
Mg-2.7Nd-0.2Zn-0.4Zr （mass fraction, %） alloy was designed for degradable biomedical material. The ingots of the alloy were solution treated and then hot extruded. The extruded rods were heat treated with aging trea...Mg-2.7Nd-0.2Zn-0.4Zr （mass fraction, %） alloy was designed for degradable biomedical material. The ingots of the alloy were solution treated and then hot extruded. The extruded rods were heat treated with aging treatment, solution treatment and solution＋aging treatment, respectively. Microstructures of the alloy were observed by optical microscopy （OM） and scanning electron microscopy （SEM）. Mechanical properties at room temperature were tested. In vitro degradation behavior of the alloy immersed in simulated body fluid was measured by hydrogen evolution and mass loss tests. The degradation morphologies of the alloy with and without degradation products were observed by SEM. The results show that the grains grow apparently after solution treatment. Solution treatment improves the elongation of as-extruded alloy significantly and decreases the strength, while aging treatment improves the strength and reduces the elongation of the alloy. The yield ratio is reduced by heat treatment. The in vitro degradation results of the alloy show that solution treatment on the as-extruded alloy results in a little higher degradation rate and aging treatment on the alloy can reduce degradation rate slightly.展开更多
As yet,Mg alloys acting as the medical implants have drawn extensive attention,due to their spontaneous degrada bility,effective load-transmissibility and the excellent biocompatibility,particularly in bone tissue rec...As yet,Mg alloys acting as the medical implants have drawn extensive attention,due to their spontaneous degrada bility,effective load-transmissibility and the excellent biocompatibility,particularly in bone tissue reconstruction and vascular radial-support.Regrettably,they were inevitably affected by the tension/compression-torsion,dynamic erosion and corrosion fatigue under complex service conditions,which lead to premature failure of implantation-materials.Micro-alloying addition is an effective way to delay the rapid degradation,especially in rare-earth micro-composite addition.It can not only reduce intensities of galvanic-corrosion by refining the grain sizes and adjusting the Volta-potentials distribution of the precipitates,but also modify the compositions and biocompatibility of the degradation products.Moreover,the higher compress tress on the surface can improve the stability and densification of the film layer,which enhanced the corrosion resistance.Thus,the latest research progress about in vivo/vitro degradation behavio rs and bioco mpatibility of rare-earth Mg alloys is reviewed;The internal relationships between rare-earth elements,phase features and degradation behaviors of Mg alloys are summarized.Moreover,the effects of rare-earth addition on the film-characteristics are deeply explained,and the induced mechanisms of rare earth elements on the biocompatibility are revealed.展开更多
Following the footsteps of biodegradable Mg-based and Fe-based alloys,biodegradable Zn-based alloy is a newcomer and rising star in the family of biodegradable metals and alloys.The combined superior mechanical proper...Following the footsteps of biodegradable Mg-based and Fe-based alloys,biodegradable Zn-based alloy is a newcomer and rising star in the family of biodegradable metals and alloys.The combined superior mechanical properties,appropriate degradation rates,excellent biocompatibility of biodegradable Zn-based alloys have brought worldwide research interest on the design,development and clinical translation of Zn-based alloys.The present perspective has summarized opportunities and challenges in the development of biodegradable Zn-based alloys.展开更多
Zinc(Zn) and its alloys have been proposed as biodegradable implant materials due to their unique combination of biodegradability, biocompatibility, and biofunctionality. However, the insufficient mechanical propertie...Zinc(Zn) and its alloys have been proposed as biodegradable implant materials due to their unique combination of biodegradability, biocompatibility, and biofunctionality. However, the insufficient mechanical properties of pure Zn greatly limit its clinical application. Here, we report on the microstructure, mechanical properties, friction and wear behavior, corrosion and degradation properties, hemocompatibility, and cytocompatibility of Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys under three different conditions of as-cast(AC),hot-rolling(HR), and hot-rolling plus cold-rolling(HR + CR). The HR + CR Zn–3 Cu–0.2 Ti exhibited the best set of comprehensive properties among all the alloy samples, with yield strength of 211.0 MPa, ultimate strength of 271.1 MPa, and elongation of 72.1 %. Immersion tests of the Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys in Hanks’ solution for 3 months indicated that the AC samples showed the lowest degradation rate,followed by the HR samples, and then the HR + CR samples, while the HR + CR Zn–3 Cu exhibited the highest degradation rate of 23.9 m/a. Friction and wear testing of the Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys in Hanks’ solution indicated that the AC samples showed the highest wear resistance, followed by the HR samples, and then the HR + CR samples, while the AC Zn–3 Cu–0.2 Ti showed the highest wear resistance.The diluted extracts of HR + CR Zn–3 Cu and Zn–3 Cu–0.2 Ti at a concentration of ≤25 % exhibited noncytotoxicity. Furthermore, both the HR + CR Zn–3 Cu and Zn–3 Cu–0.2 Ti exhibited effective antibacterial properties against S. aureus.展开更多
The degradation mechanism of electrochemical performance of sealed type nickel/metal hydride batteries was investigated. The results indicate that the degradation behavior of Ni/MH battery is not only owing to the l...The degradation mechanism of electrochemical performance of sealed type nickel/metal hydride batteries was investigated. The results indicate that the degradation behavior of Ni/MH battery is not only owing to the lack of electrolyte, but also the deterioration of the active materials on the positive and negative electrodes of Ni/MH batteries. Scanning electron micrographs (SEM), X ray diffraction (XRD) and laser granularity analyses are presented. The particle pulverization and oxidation during charge/discharge are identified as the main causes for deterioration of the negative and positive electrode in nickel/metal hydride batteries, as well as the cross section cracking of both anode and cathode.展开更多
Degradation behaviors of three typical La-Mg-Ni alloys, La2MgNi9, La1.5Mg0.5Ni7 and La4MgNi19, were studied. La1.5- Mg0.5Ni7 with （La,Mg）2Ni7 as main phase presents better discharge capacity and cycling stability. T...Degradation behaviors of three typical La-Mg-Ni alloys, La2MgNi9, La1.5Mg0.5Ni7 and La4MgNi19, were studied. La1.5- Mg0.5Ni7 with （La,Mg）2Ni7 as main phase presents better discharge capacity and cycling stability. The three alloys suffer severe pulverization and corrosion after electrochemical cycles, which are considered to be the significant factor attributing to the capacity deterioration. However, the overall corrosion extent of the three cycled alloys aggravates successively, which is inconsistent with the result that LaEMgNi9 presented poor cycling stability and also the assumption that alloy with high Mg content is easy to be corroded. The intrinsic anti-corrosion and anti-pulverization characteristics of the three alloys are mainly focused in this work. Immersion corrosion experiments demonstrate that the Mg-rich phases are more easily to be corroded. The corrosion resistance of the three alloys presents an improved trend which is inversely proportional to abundance of the Mg-rich phases. However, the anti-pulverization abilities present an inverse trend, which is closely related to the mechanical property of various phase structures. LaNi5 with the highest hardness is easy to crack, but the soft （La,Mg）Ni2 is more resistant to crack formation and spreading. Thus, the weaker corrosion of La2MgNi9 after electro- chemical cycling is attributed to the better intrinsic anti-pulverization capability though the anti-corrosion is poor. As La4MgNi19 possesses excellent corrosion resistance, enhancement of the anti-pulverization ability is urgent for improvement in the cycling stability.展开更多
Biodegradable magnesium(Mg)alloys exhibit excellent biocompatibility,adequate mechanical properties,and osteogenic effect.They can contribute to complete recovery of damaged tissues without concerns about a second sur...Biodegradable magnesium(Mg)alloys exhibit excellent biocompatibility,adequate mechanical properties,and osteogenic effect.They can contribute to complete recovery of damaged tissues without concerns about a second surgery and have achieved clinical applications in orthopedic and cardiovascular fields.Porous scaffolds can provide functions such as bone integration and adjustable mechanical properties,thus widely used for bone repair.Additive manufacturing(AM)offers the advantages of design freedom and high precision,enabling the reliable production of porous scaffolds with customized structures.The combination of biodegradable Mg alloys,porous scaffolds,and AM processes has created tremendous opportunities for the precision treatment of bone defects.This article reviews the current development in the additive manufacturing process and design of Mg alloy biodegradable orthopedic implants,fo-cusing on chemical compositions,structural design,surface treatment,and their effects on mechanical properties,degradation behavior,and biocompatibility.Finally,the future perspective of porous Mg alloy biodegradable orthopedic implants is proposed.展开更多
The microstructures,mechanical properties and in vitro degradation behavior of as-extruded pure Zn and Zn-x Sr(x=0.1,0.4,0.8 wt.%)alloys were investigated systematically.For the microstructure and mechanical propertie...The microstructures,mechanical properties and in vitro degradation behavior of as-extruded pure Zn and Zn-x Sr(x=0.1,0.4,0.8 wt.%)alloys were investigated systematically.For the microstructure and mechanical properties,Sr Zn13 phase was newly formed due to the addition of 0.1 wt.%Sr,improving the yield strength,ultimate tensile strength and elongation from(85.33±2.86)MPa,(106.00±1.41)MPa and(15.37±0.57)%for pure Zn to(107.67±2.05)MPa,(115.67±2.52)MPa and(20.80±2.19)%for Zn-0.1Sr,respectively.However,further increase of Sr content led to the deterioration of the mechanical properties due to the stress concentration and cracks initiation caused by the coarsening Sr Zn13 particles during tensile tests.For in vitro degradation,since micro galvanic corrosion was enhanced owing to the formation of the inhomogeneously distributed Sr Zn13 phase,the corrosion mode became non-uniform.Corrosion rate is gradually increased with the addition of Sr,which is increased from(11.45±2.02)μm/a(a=year)for pure Zn to(32.59±3.40)μm/a for Zn-0.8Sr.To sum up,the as-extruded Zn-0.1Sr alloy exhibited the best combination of mechanical properties and degradation behavior.展开更多
Zinc(Zn)and its biocompatible and biodegradable alloys have substantial potential for use in orthopedic implants.Nevertheless,pure Zn with a hexagonal close-packed crystal structure has only two independent slip syste...Zinc(Zn)and its biocompatible and biodegradable alloys have substantial potential for use in orthopedic implants.Nevertheless,pure Zn with a hexagonal close-packed crystal structure has only two independent slip systems,therefore exhibiting extremely low elongation and yield strength in its ascast condition,which restricts its clinical applications.In this study,as-cast Zn–xTi(titanium)(x=0.05,0.10,0.20,and 0.30 wt.%)binary alloys were hot-rolled and their microstructures,mechanical properties,wear resistance,and cytocompatibility were comprehensively investigated for orthopedic implant applications.The microstructures of both as-cast and hot-rolled Zn–xTi alloys consisted of anα-Zn matrix phase and a TiZn16 phase,while Zn–0.2 Ti and Zn–0.3 Ti exhibited a finerα-Zn phase due to the grainrefining effect of Ti.The hot-rolled Zn–0.2 Ti alloy exhibited the highest yield strength(144.5 MPa),ultimate strength(218.7 MPa),and elongation(54.2%)among all the Zn–x Ti alloys.The corrosion resistance of Zn–xTi alloys in Hanks’solution decreased with increasing addition of Ti,and the hot-rolled Zn–0.3 Ti alloy exhibited the highest corrosion rates of 432μm/y as measured by electrochemical testing and 57.9μm/y as measured by immersion testing.The as-cast Zn–xTi alloys showed lower wear losses than their hot-rolled counterparts.The extracts of hot-rolled Zn–x Ti alloys at concentrations of≤25%showed no cytotoxicity to MG-63 osteosarcoma cells and the extracts of Zn–xTi alloys exhibited enhanced cytocompatibility with increasing Ti content.展开更多
The effect of small changes in sintering temperature on microstructure, electrical properties, dielectric characteristics, and degradation behavior of V-Mn-Nb-Gd co-doped zinc oxide ceramics was investigated. With the...The effect of small changes in sintering temperature on microstructure, electrical properties, dielectric characteristics, and degradation behavior of V-Mn-Nb-Gd co-doped zinc oxide ceramics was investigated. With the increase of sintering temperature, the densities of the sintered pellets decreased from 5.54 to 5.42 g/cm3 and the average grain size increased from 4.1 to 11.7 μm. The breakdown field(E1 m A) decreased noticeably from 7138 to 920 V/cm with the increase of sintering temperature. The varistor ceramics sintered at 900 ℃ exhibited excellent nonohmic properties, which were 66 for the nonohmic coefficient and 77 μA/cm2 for the leakage current density. Concerning stability, the varistors sintered at 900 ℃ exhibited the strongest accelerated degradation characteristics, with ΔE1 mA =-9.2% for DC accelerated degradation stress of 0.85 E1 m A at 85 °C for 24 h.展开更多
When an orthopedics device is implanted into bone injury site, it will contact the soft tissue （skeletal muscle, fascia, ligament etc.） except for bone. Magnesium based biodegradable metals are becoming an important...When an orthopedics device is implanted into bone injury site, it will contact the soft tissue （skeletal muscle, fascia, ligament etc.） except for bone. Magnesium based biodegradable metals are becoming an important research object in orthopedics due to their bioactivity to promote bone healing. In this study, pure Mg rods with and without chemical conversion coating were implanted into the muscle tissue of rabbits. Implants and their surrounding tissues were taken out for weight loss measurement, cross- sectional scanning electron microscopy observation, elemental distribution analysis and histological examination. The results showed that the chemical conversion coating would increase the in vivo cor- rosion resistance of pure Mg and decrease the accumulation of calcium （Ca） and phosphorus （P） elements around the implants. For the bare magnesium implant, both Ca and P contents in the surrounding tissues increased at the initial stage of implantation and then decreased at 12 weeks implantation, while for the magnesium with chemical conversion coating, Ca and P contents in the surrounding tissues de- creased with the implantation time, but were not significant. The histological results demonstrated that there was no calcification in the muscle tissue with implantation of magnesium for up to 12 weeks. The chemical conversion coating not only increased the in vivo corrosion resistance of pure Mg, but also avoided the depositions of Ca and P in the surrounding tissues, meaning that pure magnesium should be biosafe when contacting with muscle tissues,展开更多
A biodegradable Mg−2Zn−0.4Sc−0.2Zr(ZK20−0.4Sc)alloy wire with a diameter of 0.5 mm was prepared by a combination of hot extrusion and cold-drawing.The average grain size of ZK20−0.4Sc alloy wire on the longitudinal se...A biodegradable Mg−2Zn−0.4Sc−0.2Zr(ZK20−0.4Sc)alloy wire with a diameter of 0.5 mm was prepared by a combination of hot extrusion and cold-drawing.The average grain size of ZK20−0.4Sc alloy wire on the longitudinal section along the drawing direction is approximately 7.3μm.The texture results show relatively strong<1020>and weak<1010>fiber texture components parallel to the drawing direction.The ZK20−0.4Sc alloy wire exhibits better mechanical properties with the tensile strength,yield strength and elongate of(329±2)MPa,(287±2)MPa and(14.2±0.5)%,respectively.The better mechanical properties are mainly attributed to the grain refinement strengthening,dislocation strengthening and precipitation strengthening.With the immersion time increasing to 14 d,the corrosion type transfers from filament corrosion and pitting corrosion to severe localized corrosion.展开更多
The present work focuses on the structural stability upon hydrogenation of three typical La-Mg-Ni-based alloys： La2 MgNi9, LaaMgNi14 and La4MgNi19. Structural changes during gaseous and electrochemical cycles were ch...The present work focuses on the structural stability upon hydrogenation of three typical La-Mg-Ni-based alloys： La2 MgNi9, LaaMgNi14 and La4MgNi19. Structural changes during gaseous and electrochemical cycles were characterized, and the influence of the structure distortion on the hydrogen storage properties was concerned. Hydrogen-induced amor- phization （HIA） and disproportionation of the three alloys have occurred during both the gaseous and electrochemical cycles. Structural stability of the phase structures in the La-Mg-Ni system is found to follow the order： LaNi5- 〉 （La,Mg）5Ni19 〉 （La,Mg）2Ni7 〉 （La,Mg）Ni3 〉 （La,Mg）Ni2. HIA increases thermal stability of the metal hydrides and difficulty to dehydrogenation and leads to degradation of both the gaseous and electrochemical capacities. Interestingly, LaEMgNi9 with poor stability presents elevated discharge capability even at 60 ℃ which can be attributed to increase in the hydrogen desorption capability and inhibition of the self-discharge induced by severe HIA at higher temperatures. In addition, HIA in the electrochemical reactions is obviously weaker than the extent during the gaseous cycles, which is mainly due to the slower hydrogenation speed. The development of HIA in the gaseous and electrochemical process is considered to follow the direct and gradual modes, respectively.展开更多
We investigated the aging effect on the chemical structure of silicone rubber composite materials under outdoor environment. The variations of low molecular weight siloxanes in silicone rubber were probed by gas chrom...We investigated the aging effect on the chemical structure of silicone rubber composite materials under outdoor environment. The variations of low molecular weight siloxanes in silicone rubber were probed by gas chromatography-mass spectrometry during the degradation process. The experimental results indicate that a series of cyclic siloxanes exist in both the virgin and aged silicone rubber samples, while the additional low molecular weight siloxanes（hexamethyl cyclotrisiloxane） only appear in the aged samples. Meanwhile, the total amounts of low molecular weight siloxanes in the aged samples are much less than those in the virgin ones. The loss of low molecular weight siloxanes is induced by the chain scission and depolymerization.展开更多
Laser powder bed fusion(LPBF)additive manufacturing of zinc(Zn)offers promising advantages for biodegradable metal bone implants,including tailorable microstructures,controllable porous structures,and appropriate degr...Laser powder bed fusion(LPBF)additive manufacturing of zinc(Zn)offers promising advantages for biodegradable metal bone implants,including tailorable microstructures,controllable porous structures,and appropriate degradation rates.However,the layer-by-layer construction during LPBF often leads to microstructural and performance anisotropy within metallic materials.In this work,the anisotropic mechanical and degradation properties of pure Zn processed using LPBF were comprehensively investigated for the first time.Specifically,the influence of microstructural characteristics on the mechanical and degradation properties of LPBF-processed Zn in both horizontal and vertical planes was revealed,while the underlying deformation mechanisms in different planes were illustrated.The results demonstrated that the horizontal plane exhibited higher mechanical strength compared to the vertical plane,with ulti-mate tensile strength of 123.6 and 107.86 MPa,respectively,significantly surpassing that of the tradition-ally cast counterpart(52.7 MPa).Importantly,abundant deformation twins coupled with infrequent microbands and pyramidal(c+a)slip systems activated during tensile loading along the vertical plane enabled multiple deformation modes,which sustained durable work hardening ability while delaying plastic instability,resulting in extraordinary plasticity(elongation of 14.2%).Additionally,synergistic effects between high-density grain boundaries including low-angle grain boundaries and pre-existing dislocations promoted the stable presence of a passive film along the horizontal plane,thus exhibiting relatively low corrosion sensitivity.Furthermore,the LPBF-processed Zn also demonstrated favorable biological activity and osteogenic potential.These findings provide valuable insights into multiple mechanisms underlying anisotropy in mechanical and degradation properties of laser additively manufactured Zn-based materials.展开更多
Biodegradable magnesium(Mg) and its alloy show huge potential as temporary bone substitute due to the favorable biocompatibility and mechanical compatibility. However, one issue deserves attention is the too fast degr...Biodegradable magnesium(Mg) and its alloy show huge potential as temporary bone substitute due to the favorable biocompatibility and mechanical compatibility. However, one issue deserves attention is the too fast degradation. In this work, mesoporous bioglass(MBG)with high pore volume(0.59 cc/g) and huge specific surface area(110.78 m^(2)/g) was synthesized using improved sol-gel method, and introduced into Mg-based composite via laser additive manufacturing. Immersion tests showed that the incorporated MBG served as powerful adsorption sites, which promoted the in-situ deposition of apatite by successively adsorbing Ca2+and HPO42-. Such dense apatite film acted as an efficient protection layer and enhanced the corrosion resistance of Mg matrix, which was proved by the electrochemical impedance spectroscopy measurements. Thereby, Mg based composite showed a significantly decreased degradation rate of 0.31 mm/year. Furthermore,MBG also improved the mechanical properties as well as cell behavior. This work highlighted the advantages of MBG in the fabrication of Mg-based implant with enhanced overall performance for orthopedic application.展开更多
The slow degration of iron limits its bone implant application.The solid solution of Zn in Fe is expected to accelerate the degradation.In this work,mechanical alloying(MA)was used to prepare Fe-Zn powder with supersa...The slow degration of iron limits its bone implant application.The solid solution of Zn in Fe is expected to accelerate the degradation.In this work,mechanical alloying(MA)was used to prepare Fe-Zn powder with supersaturated solid solution.MA significantly decreased the lamellar spacing between particles,thus reducing the diffusion distance of solution atoms.Moreover,it caused a number of crystalline defects,which further promoted the solution diffusion.Subsequently,the MA-processed powder was consolidated into Fe-Zn part by laser sintering,which involved a partial melting/rapid solidification mechanism and retained the original supersaturated solid solution.Results proved that the Fe-Zn alloy became more susceptible with a lowered corrosion potential,and thereby an accelerated corrosion rate of(0.112±0.013)mm/year.Furthermore,it also exhibited favorable cell behavior.This work highlighted the advantage of MA combined with laser sintering for the preparation of Fe-Zn implant with improved degradation performance.展开更多
基金supported by the National Natural Science Foundation of China(52127801)Postdoctoral Fellowship Program of CPSF under Grant Number GZC20231545,China Postdoctoral Science Foundation(2024T170557 and 2023M742224)+1 种基金Shanghai Post-doctoral Excellence Program(No.2023440)City University of Hong Kong Donation Grants(DON-RMG No.9229021 and 9220061).
文摘Pure Mg boasting a relatively small corrosion rate is a potential biodegradable metal material for implants.However,its degradation behavior in the complex physiological environment is still a lack of understanding.In this work,we investigated the effect of corrosion product film layers on the degradation behavior of pure Mg in physiological environments.Pure Mg shows a faster corrosion rate in simulated body fluid(SBF)compared to NaCl solution.Hydrogen evolution experiments indicate that the degradation rate of pure Mg in SBF decreases rapidly within the first 12 h but stabilizes afterward.The rapid deposition of low-solubility calcium phosphate on the pure Mg in SBF provides protection to the substrate,resulting in a gradual decrease in the degradation rates.Consequently,the corrosion product film of pure Mg formed in SBF exhibits a layered structure,with the upper layer consisting of dense Ca_(3)(PO_(4))_(2)/Mg_(3)(PO_(4))_(2) and the lower layer consisting of Mg(OH)_(2)/MgO.Electrochemical impedance spectroscopy(EIS)shows that the resistance of the corrosion product film increases over time,indicating gradual strengthening of the corrosion resistance.The 4-week degradation results in the femoral marrow cavity of mice are consistent with the result in SBF in vitro.
基金supported by Project of Zhongyuan Critical Metals Laboratory(GJJSGFYQ202406)National Natural Science Foundation of China(51701184,51671175)Young Backbone Teachers Foundation of Zhengzhou University.
文摘Magnesium(Mg)alloys have excellent biocompatibility and biodegradability,making them promising for clinical applications.However,their rapid degradation compared to bone healing limits their effectiveness.In this study,low-intensity pulsed ultrasound(LIPUS),widely used clinically to promote bone healing,was combined with Mg alloy scaffolds to evaluate scaffold degradation under dynamic conditions,in vitro using Hanks’balanced salt solution+BSA solution and in vivo in the femoral condyles of male SD rats.Results showed that LIPUS accelerated the initial degradation of the scaffold in both in vivo and in vitro experiments.In vitro,LIPUS increased BSA adsorption on scaffold surfaces,with adsorption increasing alongside LIPUS intensity.Limited BSA replenishment led to a thin organic-inorganic film that provided weak resistance to corrosive ions,accelerating degradation.Cavitation induced by LIPUS caused microbubble collapse,detaching Ca-P salts from scaffold surfaces.In vivo,LIPUS enhanced cell membrane permeability and activity,promoting the secretion of substances that formed a thicker organic-inorganic composite layer.Continuous material replenishment in the in vivo environment ensured the protective effect of this layer against corrosive ions,while embedded Ca-P salts were less likely to detach.In addition,LIPUS promotes bone modification.These findings highlight the potential of combining LIPUS with Mg alloys to regulate scaffold degradation,offering innovative strategies for clinical bone repair.
基金supported by the Key Research and Development Program of Shanxi Province(202102130501007)the Natural Science Foundation of Shanxi Province(202403021212109,202203021211173)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2024L039).
文摘Zinc(Zn)-based materials show broad application prospects for bone repair due to their biodegradability and good biocompatibility.In particular,Zn metal foam has unique interconnected pore structure that facilitates inward growth of new bone tissue,making it ideal candidates for orthopedic implants.However,pure Zn metal foam shows poor mechanical property,high degradation rate,and unsatisfactory osteogenic activity.Herein,Zinc-manganese(Zn-Mn)alloy foams were electrodeposited in Zn and Mn-containing electrolytes to overcome the concerns.The results showed that Mn could be incorporated into the foams in the form of MnZn_(13).Zn-Mn alloy foams showed better mechanical property and osteogenic activity as well as moderate degradation rate when compared with pure Zn metal foam.In addition,these properties could also be regulated by preparation process.The peak stress and osteogenic activity increased with deposition current(0.3‒0.5 A)and electrolyte pH(3‒5),but decreased with electrolyte temperature(20‒40℃),while the degradation rate exhibited opposite tendency,which suggests high deposition current and electrolyte pH and low electrolyte temperature can fabricate Zn-Mn alloy foam with favorable mechanical property,moderate degradation rate,and osteogenic activity.These findings provide a valuable reference for the design and fabrication of novel Zn-based biodegradable materials.
基金supported by the Introducing Talents Funds of Nanjing Institute of Technology,ChinaProject(20100470030) supported by the China Postdoctoral Science Foundation
文摘Mg-2.7Nd-0.2Zn-0.4Zr （mass fraction, %） alloy was designed for degradable biomedical material. The ingots of the alloy were solution treated and then hot extruded. The extruded rods were heat treated with aging treatment, solution treatment and solution＋aging treatment, respectively. Microstructures of the alloy were observed by optical microscopy （OM） and scanning electron microscopy （SEM）. Mechanical properties at room temperature were tested. In vitro degradation behavior of the alloy immersed in simulated body fluid was measured by hydrogen evolution and mass loss tests. The degradation morphologies of the alloy with and without degradation products were observed by SEM. The results show that the grains grow apparently after solution treatment. Solution treatment improves the elongation of as-extruded alloy significantly and decreases the strength, while aging treatment improves the strength and reduces the elongation of the alloy. The yield ratio is reduced by heat treatment. The in vitro degradation results of the alloy show that solution treatment on the as-extruded alloy results in a little higher degradation rate and aging treatment on the alloy can reduce degradation rate slightly.
基金Project supported by the Central Government Guided Local Science and Technology Development Funds (226Z1004G)Natural Science Foundation of Hebei Province (E2020209153)State Key Lab of Advanced Metals and Materials (2020-Z12)。
文摘As yet,Mg alloys acting as the medical implants have drawn extensive attention,due to their spontaneous degrada bility,effective load-transmissibility and the excellent biocompatibility,particularly in bone tissue reconstruction and vascular radial-support.Regrettably,they were inevitably affected by the tension/compression-torsion,dynamic erosion and corrosion fatigue under complex service conditions,which lead to premature failure of implantation-materials.Micro-alloying addition is an effective way to delay the rapid degradation,especially in rare-earth micro-composite addition.It can not only reduce intensities of galvanic-corrosion by refining the grain sizes and adjusting the Volta-potentials distribution of the precipitates,but also modify the compositions and biocompatibility of the degradation products.Moreover,the higher compress tress on the surface can improve the stability and densification of the film layer,which enhanced the corrosion resistance.Thus,the latest research progress about in vivo/vitro degradation behavio rs and bioco mpatibility of rare-earth Mg alloys is reviewed;The internal relationships between rare-earth elements,phase features and degradation behaviors of Mg alloys are summarized.Moreover,the effects of rare-earth addition on the film-characteristics are deeply explained,and the induced mechanisms of rare earth elements on the biocompatibility are revealed.
基金the National Natural Science Foundation of China(Nos.31700819 and 51871020)the Young Elite Scientists Sponsorship Program by CAST(YESS,No2018QNRC001)the Fundamental Research Funds for the Central Universities(No.06500098)。
文摘Following the footsteps of biodegradable Mg-based and Fe-based alloys,biodegradable Zn-based alloy is a newcomer and rising star in the family of biodegradable metals and alloys.The combined superior mechanical properties,appropriate degradation rates,excellent biocompatibility of biodegradable Zn-based alloys have brought worldwide research interest on the design,development and clinical translation of Zn-based alloys.The present perspective has summarized opportunities and challenges in the development of biodegradable Zn-based alloys.
基金supported financially by the Research Funds of the Wenzhou Science and Technology Bureau (Nos.ZG2019022 and 2018ZG008)support for this research by the Australian Research Council (ARC) through the Discovery Project (No.DP170102557)+1 种基金the Future Fellowship(No.FT160100252)support of the ARC Research Hub for Advanced Manufacturing of Medical Devices (No.IH150100024)。
文摘Zinc(Zn) and its alloys have been proposed as biodegradable implant materials due to their unique combination of biodegradability, biocompatibility, and biofunctionality. However, the insufficient mechanical properties of pure Zn greatly limit its clinical application. Here, we report on the microstructure, mechanical properties, friction and wear behavior, corrosion and degradation properties, hemocompatibility, and cytocompatibility of Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys under three different conditions of as-cast(AC),hot-rolling(HR), and hot-rolling plus cold-rolling(HR + CR). The HR + CR Zn–3 Cu–0.2 Ti exhibited the best set of comprehensive properties among all the alloy samples, with yield strength of 211.0 MPa, ultimate strength of 271.1 MPa, and elongation of 72.1 %. Immersion tests of the Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys in Hanks’ solution for 3 months indicated that the AC samples showed the lowest degradation rate,followed by the HR samples, and then the HR + CR samples, while the HR + CR Zn–3 Cu exhibited the highest degradation rate of 23.9 m/a. Friction and wear testing of the Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys in Hanks’ solution indicated that the AC samples showed the highest wear resistance, followed by the HR samples, and then the HR + CR samples, while the AC Zn–3 Cu–0.2 Ti showed the highest wear resistance.The diluted extracts of HR + CR Zn–3 Cu and Zn–3 Cu–0.2 Ti at a concentration of ≤25 % exhibited noncytotoxicity. Furthermore, both the HR + CR Zn–3 Cu and Zn–3 Cu–0.2 Ti exhibited effective antibacterial properties against S. aureus.
文摘The degradation mechanism of electrochemical performance of sealed type nickel/metal hydride batteries was investigated. The results indicate that the degradation behavior of Ni/MH battery is not only owing to the lack of electrolyte, but also the deterioration of the active materials on the positive and negative electrodes of Ni/MH batteries. Scanning electron micrographs (SEM), X ray diffraction (XRD) and laser granularity analyses are presented. The particle pulverization and oxidation during charge/discharge are identified as the main causes for deterioration of the negative and positive electrode in nickel/metal hydride batteries, as well as the cross section cracking of both anode and cathode.
基金supported financially by the National Natural Science Foundation of China (No. 51761032)the Natural Science Foundation Application of Inner Mongolia (No. 2014MS0526)
文摘Degradation behaviors of three typical La-Mg-Ni alloys, La2MgNi9, La1.5Mg0.5Ni7 and La4MgNi19, were studied. La1.5- Mg0.5Ni7 with （La,Mg）2Ni7 as main phase presents better discharge capacity and cycling stability. The three alloys suffer severe pulverization and corrosion after electrochemical cycles, which are considered to be the significant factor attributing to the capacity deterioration. However, the overall corrosion extent of the three cycled alloys aggravates successively, which is inconsistent with the result that LaEMgNi9 presented poor cycling stability and also the assumption that alloy with high Mg content is easy to be corroded. The intrinsic anti-corrosion and anti-pulverization characteristics of the three alloys are mainly focused in this work. Immersion corrosion experiments demonstrate that the Mg-rich phases are more easily to be corroded. The corrosion resistance of the three alloys presents an improved trend which is inversely proportional to abundance of the Mg-rich phases. However, the anti-pulverization abilities present an inverse trend, which is closely related to the mechanical property of various phase structures. LaNi5 with the highest hardness is easy to crack, but the soft （La,Mg）Ni2 is more resistant to crack formation and spreading. Thus, the weaker corrosion of La2MgNi9 after electro- chemical cycling is attributed to the better intrinsic anti-pulverization capability though the anti-corrosion is poor. As La4MgNi19 possesses excellent corrosion resistance, enhancement of the anti-pulverization ability is urgent for improvement in the cycling stability.
基金funded by the National Key Research and Devel-opment Program of China(2018YFE0104200)the National Natural Science Foundation of China(52175274,82172065,and 51875310)+1 种基金the Tsinghua-Toyota Joint Research Fund,the Tsinghua Precision Medicine Foundationthe Cross-Strait Tsinghua Research Insti-tute Fund.
文摘Biodegradable magnesium(Mg)alloys exhibit excellent biocompatibility,adequate mechanical properties,and osteogenic effect.They can contribute to complete recovery of damaged tissues without concerns about a second surgery and have achieved clinical applications in orthopedic and cardiovascular fields.Porous scaffolds can provide functions such as bone integration and adjustable mechanical properties,thus widely used for bone repair.Additive manufacturing(AM)offers the advantages of design freedom and high precision,enabling the reliable production of porous scaffolds with customized structures.The combination of biodegradable Mg alloys,porous scaffolds,and AM processes has created tremendous opportunities for the precision treatment of bone defects.This article reviews the current development in the additive manufacturing process and design of Mg alloy biodegradable orthopedic implants,fo-cusing on chemical compositions,structural design,surface treatment,and their effects on mechanical properties,degradation behavior,and biocompatibility.Finally,the future perspective of porous Mg alloy biodegradable orthopedic implants is proposed.
基金Project(17XD1402100)supported by the Science and Technology Commission of Shanghai Municipality,ChinaProject(SZSM201612092)supported by Shenzhen Three Renowned Project,China+1 种基金Project(2018RC001A-18)supported by the Innovation Talent Program of Karamay City,ChinaProject(2018D01A07)supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region,China。
文摘The microstructures,mechanical properties and in vitro degradation behavior of as-extruded pure Zn and Zn-x Sr(x=0.1,0.4,0.8 wt.%)alloys were investigated systematically.For the microstructure and mechanical properties,Sr Zn13 phase was newly formed due to the addition of 0.1 wt.%Sr,improving the yield strength,ultimate tensile strength and elongation from(85.33±2.86)MPa,(106.00±1.41)MPa and(15.37±0.57)%for pure Zn to(107.67±2.05)MPa,(115.67±2.52)MPa and(20.80±2.19)%for Zn-0.1Sr,respectively.However,further increase of Sr content led to the deterioration of the mechanical properties due to the stress concentration and cracks initiation caused by the coarsening Sr Zn13 particles during tensile tests.For in vitro degradation,since micro galvanic corrosion was enhanced owing to the formation of the inhomogeneously distributed Sr Zn13 phase,the corrosion mode became non-uniform.Corrosion rate is gradually increased with the addition of Sr,which is increased from(11.45±2.02)μm/a(a=year)for pure Zn to(32.59±3.40)μm/a for Zn-0.8Sr.To sum up,the as-extruded Zn-0.1Sr alloy exhibited the best combination of mechanical properties and degradation behavior.
基金the Wenzhou Science and Technology Bureau through the project ZG2019022 and 2018ZG008financial support for this research by the Australian Research Council(ARC)through the Discovery Project DP170102557+1 种基金Future Fellowship FT160100252the support of the ARC Research Hub for Advanced Manufacturing of Medical Devices(IH150100024)。
文摘Zinc(Zn)and its biocompatible and biodegradable alloys have substantial potential for use in orthopedic implants.Nevertheless,pure Zn with a hexagonal close-packed crystal structure has only two independent slip systems,therefore exhibiting extremely low elongation and yield strength in its ascast condition,which restricts its clinical applications.In this study,as-cast Zn–xTi(titanium)(x=0.05,0.10,0.20,and 0.30 wt.%)binary alloys were hot-rolled and their microstructures,mechanical properties,wear resistance,and cytocompatibility were comprehensively investigated for orthopedic implant applications.The microstructures of both as-cast and hot-rolled Zn–xTi alloys consisted of anα-Zn matrix phase and a TiZn16 phase,while Zn–0.2 Ti and Zn–0.3 Ti exhibited a finerα-Zn phase due to the grainrefining effect of Ti.The hot-rolled Zn–0.2 Ti alloy exhibited the highest yield strength(144.5 MPa),ultimate strength(218.7 MPa),and elongation(54.2%)among all the Zn–x Ti alloys.The corrosion resistance of Zn–xTi alloys in Hanks’solution decreased with increasing addition of Ti,and the hot-rolled Zn–0.3 Ti alloy exhibited the highest corrosion rates of 432μm/y as measured by electrochemical testing and 57.9μm/y as measured by immersion testing.The as-cast Zn–xTi alloys showed lower wear losses than their hot-rolled counterparts.The extracts of hot-rolled Zn–x Ti alloys at concentrations of≤25%showed no cytotoxicity to MG-63 osteosarcoma cells and the extracts of Zn–xTi alloys exhibited enhanced cytocompatibility with increasing Ti content.
文摘The effect of small changes in sintering temperature on microstructure, electrical properties, dielectric characteristics, and degradation behavior of V-Mn-Nb-Gd co-doped zinc oxide ceramics was investigated. With the increase of sintering temperature, the densities of the sintered pellets decreased from 5.54 to 5.42 g/cm3 and the average grain size increased from 4.1 to 11.7 μm. The breakdown field(E1 m A) decreased noticeably from 7138 to 920 V/cm with the increase of sintering temperature. The varistor ceramics sintered at 900 ℃ exhibited excellent nonohmic properties, which were 66 for the nonohmic coefficient and 77 μA/cm2 for the leakage current density. Concerning stability, the varistors sintered at 900 ℃ exhibited the strongest accelerated degradation characteristics, with ΔE1 mA =-9.2% for DC accelerated degradation stress of 0.85 E1 m A at 85 °C for 24 h.
基金financially supported by the National Science & Technology Pillar Program of China (No. 2012BAI18B01)the National Basic Research Program of China ("973 Program", No. 2012CB619101)+1 种基金the National Natural Science Foundation of China (No. 81171443)the Foundation of Jiangsu Collaborative Innovation Center of Biomedical Functional Materials
文摘When an orthopedics device is implanted into bone injury site, it will contact the soft tissue （skeletal muscle, fascia, ligament etc.） except for bone. Magnesium based biodegradable metals are becoming an important research object in orthopedics due to their bioactivity to promote bone healing. In this study, pure Mg rods with and without chemical conversion coating were implanted into the muscle tissue of rabbits. Implants and their surrounding tissues were taken out for weight loss measurement, cross- sectional scanning electron microscopy observation, elemental distribution analysis and histological examination. The results showed that the chemical conversion coating would increase the in vivo cor- rosion resistance of pure Mg and decrease the accumulation of calcium （Ca） and phosphorus （P） elements around the implants. For the bare magnesium implant, both Ca and P contents in the surrounding tissues increased at the initial stage of implantation and then decreased at 12 weeks implantation, while for the magnesium with chemical conversion coating, Ca and P contents in the surrounding tissues de- creased with the implantation time, but were not significant. The histological results demonstrated that there was no calcification in the muscle tissue with implantation of magnesium for up to 12 weeks. The chemical conversion coating not only increased the in vivo corrosion resistance of pure Mg, but also avoided the depositions of Ca and P in the surrounding tissues, meaning that pure magnesium should be biosafe when contacting with muscle tissues,
基金financial support from the National Nature Science Foundation of China (No.52274369)the Hunan Provincial Natural Science Foundation,China (No.2024JJ6521)。
文摘A biodegradable Mg−2Zn−0.4Sc−0.2Zr(ZK20−0.4Sc)alloy wire with a diameter of 0.5 mm was prepared by a combination of hot extrusion and cold-drawing.The average grain size of ZK20−0.4Sc alloy wire on the longitudinal section along the drawing direction is approximately 7.3μm.The texture results show relatively strong<1020>and weak<1010>fiber texture components parallel to the drawing direction.The ZK20−0.4Sc alloy wire exhibits better mechanical properties with the tensile strength,yield strength and elongate of(329±2)MPa,(287±2)MPa and(14.2±0.5)%,respectively.The better mechanical properties are mainly attributed to the grain refinement strengthening,dislocation strengthening and precipitation strengthening.With the immersion time increasing to 14 d,the corrosion type transfers from filament corrosion and pitting corrosion to severe localized corrosion.
基金supported financially by the National Natural Science Foundation of China (No.51761032)the University Foundation of Inner Mongolia (No.NJZZ18142)
文摘The present work focuses on the structural stability upon hydrogenation of three typical La-Mg-Ni-based alloys： La2 MgNi9, LaaMgNi14 and La4MgNi19. Structural changes during gaseous and electrochemical cycles were characterized, and the influence of the structure distortion on the hydrogen storage properties was concerned. Hydrogen-induced amor- phization （HIA） and disproportionation of the three alloys have occurred during both the gaseous and electrochemical cycles. Structural stability of the phase structures in the La-Mg-Ni system is found to follow the order： LaNi5- 〉 （La,Mg）5Ni19 〉 （La,Mg）2Ni7 〉 （La,Mg）Ni3 〉 （La,Mg）Ni2. HIA increases thermal stability of the metal hydrides and difficulty to dehydrogenation and leads to degradation of both the gaseous and electrochemical capacities. Interestingly, LaEMgNi9 with poor stability presents elevated discharge capability even at 60 ℃ which can be attributed to increase in the hydrogen desorption capability and inhibition of the self-discharge induced by severe HIA at higher temperatures. In addition, HIA in the electrochemical reactions is obviously weaker than the extent during the gaseous cycles, which is mainly due to the slower hydrogenation speed. The development of HIA in the gaseous and electrochemical process is considered to follow the direct and gradual modes, respectively.
基金Funded by the National Natural Science Foundation of China(21174108)the Science and Technology Project of China Southern Power Grid Co.,Ltd.(K-GD2014-185)
文摘We investigated the aging effect on the chemical structure of silicone rubber composite materials under outdoor environment. The variations of low molecular weight siloxanes in silicone rubber were probed by gas chromatography-mass spectrometry during the degradation process. The experimental results indicate that a series of cyclic siloxanes exist in both the virgin and aged silicone rubber samples, while the additional low molecular weight siloxanes（hexamethyl cyclotrisiloxane） only appear in the aged samples. Meanwhile, the total amounts of low molecular weight siloxanes in the aged samples are much less than those in the virgin ones. The loss of low molecular weight siloxanes is induced by the chain scission and depolymerization.
基金supported by the following funds:the National Natural Science Foundation of China(No.52305358)the Fundamental Research Funds for the Central Universities(No.2023ZYGXZR061)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515010304)the Young Elite Scientists Sponsorship Program by CAST(No.2023QNRC001)the Young Talent Support Project of Guangzhou(No.QT-2023-001).
文摘Laser powder bed fusion(LPBF)additive manufacturing of zinc(Zn)offers promising advantages for biodegradable metal bone implants,including tailorable microstructures,controllable porous structures,and appropriate degradation rates.However,the layer-by-layer construction during LPBF often leads to microstructural and performance anisotropy within metallic materials.In this work,the anisotropic mechanical and degradation properties of pure Zn processed using LPBF were comprehensively investigated for the first time.Specifically,the influence of microstructural characteristics on the mechanical and degradation properties of LPBF-processed Zn in both horizontal and vertical planes was revealed,while the underlying deformation mechanisms in different planes were illustrated.The results demonstrated that the horizontal plane exhibited higher mechanical strength compared to the vertical plane,with ulti-mate tensile strength of 123.6 and 107.86 MPa,respectively,significantly surpassing that of the tradition-ally cast counterpart(52.7 MPa).Importantly,abundant deformation twins coupled with infrequent microbands and pyramidal(c+a)slip systems activated during tensile loading along the vertical plane enabled multiple deformation modes,which sustained durable work hardening ability while delaying plastic instability,resulting in extraordinary plasticity(elongation of 14.2%).Additionally,synergistic effects between high-density grain boundaries including low-angle grain boundaries and pre-existing dislocations promoted the stable presence of a passive film along the horizontal plane,thus exhibiting relatively low corrosion sensitivity.Furthermore,the LPBF-processed Zn also demonstrated favorable biological activity and osteogenic potential.These findings provide valuable insights into multiple mechanisms underlying anisotropy in mechanical and degradation properties of laser additively manufactured Zn-based materials.
基金National Natural Science Foundation of China (51935014,52165043, 82072084, 81871498)Jiang Xi Provincial Natural Science Foundation of China (20192ACB20005,2020ACB214004)+6 种基金The Provincial Key R&D Projects of Jiangxi (20201BBE51012)Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme (2018)Shenzhen Science and Technology Plan Project (JCYJ20170817112445033)Innovation Team Project on University of Guangdong Province(2018GKCXTD001)Technology Innovation Platform Project of Shenzhen Institute of Information Technology 2020(PT2020E002)China Postdoctoral Science Foundation(2020M682114)Open Research Fund of Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology。
文摘Biodegradable magnesium(Mg) and its alloy show huge potential as temporary bone substitute due to the favorable biocompatibility and mechanical compatibility. However, one issue deserves attention is the too fast degradation. In this work, mesoporous bioglass(MBG)with high pore volume(0.59 cc/g) and huge specific surface area(110.78 m^(2)/g) was synthesized using improved sol-gel method, and introduced into Mg-based composite via laser additive manufacturing. Immersion tests showed that the incorporated MBG served as powerful adsorption sites, which promoted the in-situ deposition of apatite by successively adsorbing Ca2+and HPO42-. Such dense apatite film acted as an efficient protection layer and enhanced the corrosion resistance of Mg matrix, which was proved by the electrochemical impedance spectroscopy measurements. Thereby, Mg based composite showed a significantly decreased degradation rate of 0.31 mm/year. Furthermore,MBG also improved the mechanical properties as well as cell behavior. This work highlighted the advantages of MBG in the fabrication of Mg-based implant with enhanced overall performance for orthopedic application.
基金Projects(51935014,82072084,81871498)supported by the Natural Science Foundation of ChinaProjects(20192ACB20005,2020ACB214004)supported by the Jiangxi Provincial Natural Science Foundation of China+4 种基金Project(20201BBE51012)supported by the Provincial Key R&D Projects of Jiangxi Province,ChinaProject(2018)supported by the Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme,ChinaProject(2017RS3008)supported by Hunan Provincial Science and Technology Plan,ChinaProject supported by the Open Research Fund of Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology,ChinaProject(2020M682114)China Postdoctoral Science Foundation。
文摘The slow degration of iron limits its bone implant application.The solid solution of Zn in Fe is expected to accelerate the degradation.In this work,mechanical alloying(MA)was used to prepare Fe-Zn powder with supersaturated solid solution.MA significantly decreased the lamellar spacing between particles,thus reducing the diffusion distance of solution atoms.Moreover,it caused a number of crystalline defects,which further promoted the solution diffusion.Subsequently,the MA-processed powder was consolidated into Fe-Zn part by laser sintering,which involved a partial melting/rapid solidification mechanism and retained the original supersaturated solid solution.Results proved that the Fe-Zn alloy became more susceptible with a lowered corrosion potential,and thereby an accelerated corrosion rate of(0.112±0.013)mm/year.Furthermore,it also exhibited favorable cell behavior.This work highlighted the advantage of MA combined with laser sintering for the preparation of Fe-Zn implant with improved degradation performance.
