Boron nitride(BN),as a nano-reinforcement,offers notable benefits for zinc(Zn)-based implants due to its distinct asymmetric hexagonal structure and high fracture strength.However,the limited interface adhesion betwee...Boron nitride(BN),as a nano-reinforcement,offers notable benefits for zinc(Zn)-based implants due to its distinct asymmetric hexagonal structure and high fracture strength.However,the limited interface adhesion between BN and Zn limits its potential for strengthening and toughening.In this study,copper(Cu)was in situ grown on acidified BN through chemical synthesis and subsequently incorporated into laser additive manufacturing of Zn to enhance interface bonding.During this process,the Cu on BN experienced a displacement reaction with Zn due to thermal reduction induced by the high-energy laser,leading to the replacement of Cu by Zn and the formation of a robust covalent bond between BN and the Zn matrix,thereby improving load transfer.Additionally,the reduced Cu further interacted with Zn to produce the CuZn5 phase,which was evenly dispersed in the Zn matrix under Marangoni vortices,resulting in both dispersion and Orowan strengthening.Consequently,the ultimate tensile strength of the composites achieved(251±7)MPa.The fracture toughness also showed a notable increase from 12.10 to 24.03 MPa·m^(1/2),as the unique structure of BN effectively redistributed stress at the crack tip and absorbed considerable fracture energy.Furthermore,the Cu@BN/Zn implants demonstrated excellent antibacterial properties.展开更多
As-extruded Mg-Sr alloy, a kind of promising biodegradable biomedical material, was coated using micro-arc oxidation and also using a phosphate conversion coating. The corrosion behaviors were investigated using Hanks...As-extruded Mg-Sr alloy, a kind of promising biodegradable biomedical material, was coated using micro-arc oxidation and also using a phosphate conversion coating. The corrosion behaviors were investigated using Hanks' solution. The corrosion of the as-extruded Mg-Sr alloy became more serious with increasing immersion time;that is, the corrosion pits became more numerous, larger and deeper, The micro-arc oxidation coating and the phosphate conversion coating were effective in improving the corrosion resistance of the as-extruded Mg-Sr alloy. The micro-arc oxidation coating was much more effective. Moreover, the as-extruded Mg-Sr alloy and the coated as-extruded Mg-Sr alloy exhibited lower corrosion rates than the as-cast Mg-Sr alloy and the corresponding coated as-cast Mg-Sr alloy, indicating that the corrosion properties of the coated samples are dependent on their substrates. The finer microstructure of the substrate of the as-extruded condition corroded much slower. The corrosion resistance of the coated Mg-Sr alloy depended on the coating itself and on the microstructure of the substrate.展开更多
Zinc(Zn)has recently been recognized as a promising bone repair material due to its inherent biodegradability and favorable biocompatibility.In this work,rare earth neodymium(Nd)was introduced into a Zn-based alloy fa...Zinc(Zn)has recently been recognized as a promising bone repair material due to its inherent biodegradability and favorable biocompatibility.In this work,rare earth neodymium(Nd)was introduced into a Zn-based alloy fabricated using a laser powder bed fusion(LPBF)process.Results showed that addition of Nd significantly improved the melt fluidity and reduced the evaporation of Zn,thereby achieving parts with a high densification rate of 98.71%.Significantly,the Nd alloying treatment effectively refined the grain size from 25.3 to 6.2μm.Nd Zn5 eutectics precipitated and contributed to a second-phase strengthening effect.As a result,the tensile strength increased to(119.3±5.1)MPa and the Vickers hardness to(76.2±4.1).Moreover,the Zn–Nd alloy exhibited good anti-inflammatory activity,as the Nd ions released during degradation had a strong affinity with cell membrane phospholipids and consequently inhibited the release of inflammatory cytokines.It also presented favorable cytocompatibility,showing great potential as a bone repair material.展开更多
基金supported by the National Key Research and Development Program of China(No.2023YFB4605800)the Natural Science Foundation of China(Nos.51935014,52165043 and 82072084)+4 种基金Jiangxi Provincial Cultivation Program for Academic and Technical Leaders of Major Subjects(No.20225BCJ23008)Jiangxi Provincial Natural Science Foundation of China(Nos.20224ACB204013 and 20224ACB214008)the Technology Innovation Platform Project of Shenzhen Institute of Information Technology 2020(No.PT2020E002)the Shccig-Qinling Program(No.2022360702014891)Jiangxi University of Science and Technology Graduate Innovation Special Fund Project(No.XY2023-S677).
文摘Boron nitride(BN),as a nano-reinforcement,offers notable benefits for zinc(Zn)-based implants due to its distinct asymmetric hexagonal structure and high fracture strength.However,the limited interface adhesion between BN and Zn limits its potential for strengthening and toughening.In this study,copper(Cu)was in situ grown on acidified BN through chemical synthesis and subsequently incorporated into laser additive manufacturing of Zn to enhance interface bonding.During this process,the Cu on BN experienced a displacement reaction with Zn due to thermal reduction induced by the high-energy laser,leading to the replacement of Cu by Zn and the formation of a robust covalent bond between BN and the Zn matrix,thereby improving load transfer.Additionally,the reduced Cu further interacted with Zn to produce the CuZn5 phase,which was evenly dispersed in the Zn matrix under Marangoni vortices,resulting in both dispersion and Orowan strengthening.Consequently,the ultimate tensile strength of the composites achieved(251±7)MPa.The fracture toughness also showed a notable increase from 12.10 to 24.03 MPa·m^(1/2),as the unique structure of BN effectively redistributed stress at the crack tip and absorbed considerable fracture energy.Furthermore,the Cu@BN/Zn implants demonstrated excellent antibacterial properties.
基金financially supported by the National Natural Science Foundation of China (No. 51874368)
文摘As-extruded Mg-Sr alloy, a kind of promising biodegradable biomedical material, was coated using micro-arc oxidation and also using a phosphate conversion coating. The corrosion behaviors were investigated using Hanks' solution. The corrosion of the as-extruded Mg-Sr alloy became more serious with increasing immersion time;that is, the corrosion pits became more numerous, larger and deeper, The micro-arc oxidation coating and the phosphate conversion coating were effective in improving the corrosion resistance of the as-extruded Mg-Sr alloy. The micro-arc oxidation coating was much more effective. Moreover, the as-extruded Mg-Sr alloy and the coated as-extruded Mg-Sr alloy exhibited lower corrosion rates than the as-cast Mg-Sr alloy and the corresponding coated as-cast Mg-Sr alloy, indicating that the corrosion properties of the coated samples are dependent on their substrates. The finer microstructure of the substrate of the as-extruded condition corroded much slower. The corrosion resistance of the coated Mg-Sr alloy depended on the coating itself and on the microstructure of the substrate.
基金the National Natural Science Foundation of China(Nos.51935014,82072084,and 81871498)the Jiangxi Provincial Natural Science Foundation of China(Nos.20192ACB20005 and 2020ACB214004)+4 种基金the Jiangxi Provincial Key R&D Program(No.20201BBE51012)the Guangdong Provincial Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2018)the China Postdoctoral Science Foundation(No.2020M682114)the Open Research Fund of Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technologythe Project of Hunan Provincial Science and Technology Plan(No.2017RS3008),China。
文摘Zinc(Zn)has recently been recognized as a promising bone repair material due to its inherent biodegradability and favorable biocompatibility.In this work,rare earth neodymium(Nd)was introduced into a Zn-based alloy fabricated using a laser powder bed fusion(LPBF)process.Results showed that addition of Nd significantly improved the melt fluidity and reduced the evaporation of Zn,thereby achieving parts with a high densification rate of 98.71%.Significantly,the Nd alloying treatment effectively refined the grain size from 25.3 to 6.2μm.Nd Zn5 eutectics precipitated and contributed to a second-phase strengthening effect.As a result,the tensile strength increased to(119.3±5.1)MPa and the Vickers hardness to(76.2±4.1).Moreover,the Zn–Nd alloy exhibited good anti-inflammatory activity,as the Nd ions released during degradation had a strong affinity with cell membrane phospholipids and consequently inhibited the release of inflammatory cytokines.It also presented favorable cytocompatibility,showing great potential as a bone repair material.
