The high-temperature oxidation behaviour of the Inconel 625 alloy at 950℃ was investigated after different ageing treatments.The effect of heat treatment on the oxidation behaviour of the alloy was analysed by charac...The high-temperature oxidation behaviour of the Inconel 625 alloy at 950℃ was investigated after different ageing treatments.The effect of heat treatment on the oxidation behaviour of the alloy was analysed by characterizing the structure and elemental distribution before and after oxidation.The results reveal that the two ageing treatments at 650℃ for 500 h and at 750℃ for 400 h both reduced the oxidation mass gain.After oxidation at 950℃,an outer Cr_(2)O_(3) layer and inner Al_(2)O_(3) are identified as the main oxidation products.Moreover,Nb_(2)O_(5) andδ(Ni_(3)Nb)phases precipitated after oxidation.The ageing treatments cause the rapid generation of a dense Cr_(2)O_(3) layer on the surface,which prevents the diffusion of oxygen into the matrix,reduce the Al_(2)O_(3) inward growth depth,and improve the oxidation resistance of the alloy.展开更多
The process of preparing anodic oxide film containing active sites and electroless nickel plating on highly active rare earth magnesium alloy was developed.The formation mechanism of electroless nickel plating on acti...The process of preparing anodic oxide film containing active sites and electroless nickel plating on highly active rare earth magnesium alloy was developed.The formation mechanism of electroless nickel plating on active anodic oxide film and the structure and properties of the composite coating were studied by several surface and electrochemical techniques.The results showed that Ag nanograins with an average size of 10 nm were embedded into the anodic oxide film with pores of 0.1−2μm.Ag nanoparticles provided a catalytic site for the deposition of Ni-B alloy,and the Ni crystal nucleus was first grown in horizontal mode and then in cylindrical mode.The corrosion potential of the composite coating increased by 1.37 V and the corrosion current reduced two orders of magnitude due to the subsequent deposition of Ni-P alloy.The high corrosion resistance was attributed to the misaligning of these micro defects in the three different layers and the amorphous structure of the Ni-P alloy in the outer layer.These findings provide a new idea for electroless nickel plating on anodic oxide film.展开更多
The effect of thermal cycling and aging in martensitic state in Ti-Pd-Ni alloys were investigated by DSC and TEM observations. It is shown that the thermal cycling causes the decreases in M, and Af temperatures in Ti5...The effect of thermal cycling and aging in martensitic state in Ti-Pd-Ni alloys were investigated by DSC and TEM observations. It is shown that the thermal cycling causes the decreases in M, and Af temperatures in Ti50Pd50-xNix (x=10, 20, 30) alloys, but no obvious thermal cycling effect was observed in Ti50Pd50Pd40Ni10 alloys and the aging effect shows a curious feature, i.e., the Af temperature does not saturate even after relatively long time aging, which is considered to be due to the occurrence of recovery recrystallization during aging.展开更多
Mg-based hydrogen storage materials are considered to be one of the most promising solid-state hydrogen storage materials due to their large hydrogen storage capacity and low cost. However, slow hydrogen absorption/de...Mg-based hydrogen storage materials are considered to be one of the most promising solid-state hydrogen storage materials due to their large hydrogen storage capacity and low cost. However, slow hydrogen absorption/desorption rate and excessive hydrogen absorption/desorption temperature limit the application of Mg-based hydrogen storage materials.The present paper reviews the advances in the research of Mg-based hydrogen storage film in recent years, including the advantage of the film, the function theory of fabricating method and its functional theory, and the influencing factors in the technological process. The research status worldwide is introduced in detail. By comparing pure Mg, Pd-caped Mg, nonpalladium capped Mg, and Mg alloy hydrogen storage films, an ideal tendency for producing Mg-based film is pointed out,for example, looking for a cheap metal element to replace the high-priced Pd, compositing Mg film with other hydrogen storage alloy of catalytic elements, and so on.展开更多
The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide （AAO） template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to ...The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide （AAO） template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors. Scanning electron microscopy （SEM） and energy dispersed X-ray spectroscopy （EDX） were employed to characterize the morphologies and compositions of the Pd-Ag nanowires. X-ray diffraction （XRD） was used to characterize the phase properties of the Pd-Ag nanowires. Pd-Ag alloy nanowire arrays with 17.28%-23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V （vs SCE）. The sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores. The underpotential deposition of Ag＋ on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy. Alloy compositions can still be controlled by adjusting the ion concentration ratio of Pd^2＋ and Ag＋ and the electrodeposition processes. XRD shows that nanowires obtained are in the form of alloy of Pd and Ag.展开更多
The electro-catalytic properties can be effectively optimized by designing bimetallic alloy nanoparticles with high-content less-active metal to enhance the competence of more-active noble metal. Herein, a one-pot hyd...The electro-catalytic properties can be effectively optimized by designing bimetallic alloy nanoparticles with high-content less-active metal to enhance the competence of more-active noble metal. Herein, a one-pot hydrothermal approach is demonstrated for the controllable synthesis of Ag-rich Ag_9Pd_1 alloy nanoactiniae with obviously enhanced electro-catalytic activity(2.23 mA cm^(-2) at 0.85 V) and stability for oxygen reduction reaction. In alkaline solution, the ORR onset potential and half-wave potential of the Ag_9Pd_1 alloy nanoactiniae can reach a value of 1.02 V and 0.89 V, respectively, which origin from strong ligand and ensemble effects between Pd element and Ag element. The nanocrystals are uniformly alloyed, displaying a Ag_9Pd_1 combination, as displayed by an assembly of X-ray diffraction(XRD) spectrum,energy dispersive X-ray(EDX) analysis, and cyclic voltammetry(CV). This concept of tuning bimetallic alloy nanocrystals with low concentrations of more precious metal may be a promising approach to be applicable to a wide range of alloy nanocrystals.展开更多
For Ag alloy film used for the storage media, it is required to have heat-resistance, anti-constant temperature and anti-constant humidity characteristics, corrosion resistance, while high reflectivity over Al is main...For Ag alloy film used for the storage media, it is required to have heat-resistance, anti-constant temperature and anti-constant humidity characteristics, corrosion resistance, while high reflectivity over Al is maintained. An Ag alloy thin film (additive element Pd, Cu, P) was created on glass substrates, and various heat treatment was conducted. Then, fine structure was observed on this thin film using AFM, and fine structure evaluation of the inside was carried out by the in-plane diffractometry and X-ray diffractometry, and in addition, residual stress analysis was carried out. These results were compared and were examined, and fine structure and physical property in a metallic thin film were evaluated, and usefulness of evaluation method was verified.展开更多
The corrosion behaviour of Mg−6Gd−3Y−1Zn−0.3Ag(wt.%)alloy components with different sizes after cooling was investigated.The alloys in the small components(SC)cooled fast,which were composed ofα-Mg matrix and coarse ...The corrosion behaviour of Mg−6Gd−3Y−1Zn−0.3Ag(wt.%)alloy components with different sizes after cooling was investigated.The alloys in the small components(SC)cooled fast,which were composed ofα-Mg matrix and coarse long-period stacking ordered(LPSO)phases.The alloys in the large components(LC)cooled slowly,and there were thin lamellar LPSO phases precipitating inside the grains,except forα-Mg matrix and coarse LPSO phases.The hydrogen evolution test revealed that the corrosion rate of LC sample was higher than that of SC sample.Electrochemical impedance spectroscopy(EIS)test showed that the surface film on LC alloys provided worse protection.The corrosion morphologies indicated that the precipitation of the thin lamellar LPSO phases in LC sample caused severe micro-galvanic corrosion,which accelerated the rupture of the surface film.展开更多
基金financially supported by the National Science and Technology Major Project of China (Nos.MJ-2018-G-48,J2019-Ⅵ-0023-0140)the Research Fund of the State Key Laboratory of Solidification Processing (NPU),China (No.2022-TS-04)。
文摘The high-temperature oxidation behaviour of the Inconel 625 alloy at 950℃ was investigated after different ageing treatments.The effect of heat treatment on the oxidation behaviour of the alloy was analysed by characterizing the structure and elemental distribution before and after oxidation.The results reveal that the two ageing treatments at 650℃ for 500 h and at 750℃ for 400 h both reduced the oxidation mass gain.After oxidation at 950℃,an outer Cr_(2)O_(3) layer and inner Al_(2)O_(3) are identified as the main oxidation products.Moreover,Nb_(2)O_(5) andδ(Ni_(3)Nb)phases precipitated after oxidation.The ageing treatments cause the rapid generation of a dense Cr_(2)O_(3) layer on the surface,which prevents the diffusion of oxygen into the matrix,reduce the Al_(2)O_(3) inward growth depth,and improve the oxidation resistance of the alloy.
基金Project(5227010679)supported by the National Natural Science Foundation of China。
文摘The process of preparing anodic oxide film containing active sites and electroless nickel plating on highly active rare earth magnesium alloy was developed.The formation mechanism of electroless nickel plating on active anodic oxide film and the structure and properties of the composite coating were studied by several surface and electrochemical techniques.The results showed that Ag nanograins with an average size of 10 nm were embedded into the anodic oxide film with pores of 0.1−2μm.Ag nanoparticles provided a catalytic site for the deposition of Ni-B alloy,and the Ni crystal nucleus was first grown in horizontal mode and then in cylindrical mode.The corrosion potential of the composite coating increased by 1.37 V and the corrosion current reduced two orders of magnitude due to the subsequent deposition of Ni-P alloy.The high corrosion resistance was attributed to the misaligning of these micro defects in the three different layers and the amorphous structure of the Ni-P alloy in the outer layer.These findings provide a new idea for electroless nickel plating on anodic oxide film.
基金This work was supported by a Grant-in-Aid fOrEncouragement of Young Scientists (W.C.) (l998-1999) from the Ministry of Educat
文摘The effect of thermal cycling and aging in martensitic state in Ti-Pd-Ni alloys were investigated by DSC and TEM observations. It is shown that the thermal cycling causes the decreases in M, and Af temperatures in Ti50Pd50-xNix (x=10, 20, 30) alloys, but no obvious thermal cycling effect was observed in Ti50Pd50Pd40Ni10 alloys and the aging effect shows a curious feature, i.e., the Af temperature does not saturate even after relatively long time aging, which is considered to be due to the occurrence of recovery recrystallization during aging.
基金Project supported by the Competitiveness Enhancement Program of National Research Tomsk Polytechnic University(Grant No.VIU-OEF-66/2019)
文摘Mg-based hydrogen storage materials are considered to be one of the most promising solid-state hydrogen storage materials due to their large hydrogen storage capacity and low cost. However, slow hydrogen absorption/desorption rate and excessive hydrogen absorption/desorption temperature limit the application of Mg-based hydrogen storage materials.The present paper reviews the advances in the research of Mg-based hydrogen storage film in recent years, including the advantage of the film, the function theory of fabricating method and its functional theory, and the influencing factors in the technological process. The research status worldwide is introduced in detail. By comparing pure Mg, Pd-caped Mg, nonpalladium capped Mg, and Mg alloy hydrogen storage films, an ideal tendency for producing Mg-based film is pointed out,for example, looking for a cheap metal element to replace the high-priced Pd, compositing Mg film with other hydrogen storage alloy of catalytic elements, and so on.
基金supported by the National Natural Science Foundation of China under Grant No.20373015the Hunan Education Office under Grant No.04C033.
文摘The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide （AAO） template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors. Scanning electron microscopy （SEM） and energy dispersed X-ray spectroscopy （EDX） were employed to characterize the morphologies and compositions of the Pd-Ag nanowires. X-ray diffraction （XRD） was used to characterize the phase properties of the Pd-Ag nanowires. Pd-Ag alloy nanowire arrays with 17.28%-23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V （vs SCE）. The sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores. The underpotential deposition of Ag＋ on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy. Alloy compositions can still be controlled by adjusting the ion concentration ratio of Pd^2＋ and Ag＋ and the electrodeposition processes. XRD shows that nanowires obtained are in the form of alloy of Pd and Ag.
基金sponsored by the National Natural Science Foundation of China (21576139, 21503111)the Natural Science Foundation of Jiangsu Province (BK20171473)+1 种基金the National and Local Joint Engineering Research Center of Biomedical Functional Materials, Natural Science Foundation of Jiangsu Higher Education Institutions of China (16KJB150020)a project sponsored by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The electro-catalytic properties can be effectively optimized by designing bimetallic alloy nanoparticles with high-content less-active metal to enhance the competence of more-active noble metal. Herein, a one-pot hydrothermal approach is demonstrated for the controllable synthesis of Ag-rich Ag_9Pd_1 alloy nanoactiniae with obviously enhanced electro-catalytic activity(2.23 mA cm^(-2) at 0.85 V) and stability for oxygen reduction reaction. In alkaline solution, the ORR onset potential and half-wave potential of the Ag_9Pd_1 alloy nanoactiniae can reach a value of 1.02 V and 0.89 V, respectively, which origin from strong ligand and ensemble effects between Pd element and Ag element. The nanocrystals are uniformly alloyed, displaying a Ag_9Pd_1 combination, as displayed by an assembly of X-ray diffraction(XRD) spectrum,energy dispersive X-ray(EDX) analysis, and cyclic voltammetry(CV). This concept of tuning bimetallic alloy nanocrystals with low concentrations of more precious metal may be a promising approach to be applicable to a wide range of alloy nanocrystals.
文摘For Ag alloy film used for the storage media, it is required to have heat-resistance, anti-constant temperature and anti-constant humidity characteristics, corrosion resistance, while high reflectivity over Al is maintained. An Ag alloy thin film (additive element Pd, Cu, P) was created on glass substrates, and various heat treatment was conducted. Then, fine structure was observed on this thin film using AFM, and fine structure evaluation of the inside was carried out by the in-plane diffractometry and X-ray diffractometry, and in addition, residual stress analysis was carried out. These results were compared and were examined, and fine structure and physical property in a metallic thin film were evaluated, and usefulness of evaluation method was verified.
基金the financial supports from the National Natural Science foundation of China(Nos.51574291,51874367).
文摘The corrosion behaviour of Mg−6Gd−3Y−1Zn−0.3Ag(wt.%)alloy components with different sizes after cooling was investigated.The alloys in the small components(SC)cooled fast,which were composed ofα-Mg matrix and coarse long-period stacking ordered(LPSO)phases.The alloys in the large components(LC)cooled slowly,and there were thin lamellar LPSO phases precipitating inside the grains,except forα-Mg matrix and coarse LPSO phases.The hydrogen evolution test revealed that the corrosion rate of LC sample was higher than that of SC sample.Electrochemical impedance spectroscopy(EIS)test showed that the surface film on LC alloys provided worse protection.The corrosion morphologies indicated that the precipitation of the thin lamellar LPSO phases in LC sample caused severe micro-galvanic corrosion,which accelerated the rupture of the surface film.
