高性能复合镀层具有优良的耐磨、耐蚀性能,能满足工业生产对材料性能的要求。研究了脉冲电沉积RE Ni W B PTFE Al2O3 复合镀层的成分、形貌及性能。结果表明:脉冲电流及Al2O3 固体颗粒能明显提高RE Ni W B PTFE Al2O3 复合镀层中W和B的...高性能复合镀层具有优良的耐磨、耐蚀性能,能满足工业生产对材料性能的要求。研究了脉冲电沉积RE Ni W B PTFE Al2O3 复合镀层的成分、形貌及性能。结果表明:脉冲电流及Al2O3 固体颗粒能明显提高RE Ni W B PTFE Al2O3 复合镀层中W和B的含量;与直流电沉积相比,脉冲电沉积RE Ni W B复合镀层的表面裂纹已明显减小,但裂纹仍存在,当Al2O3 耐磨颗粒及PTFE减摩微粒嵌入RE Ni W B复合镀层中以后,在SEM 400倍下观察,RE Ni W B PTFE Al2O3镀层已不存在裂纹, 而且镀液中Al2O3 颗粒含量越多,晶粒就越细;此外,研究表明,镀液中Al2O3 颗粒含量增加, RE Ni W B PTFE Al2O3 复合镀层镀态硬度增加,磨损率降低。展开更多
In order to improve the wear resistance of elastic metallic-plastic thrust bearing pad, micro-assembling PTFE/Al2O3 multi-layer film was developed by alternating radio frequency（RF） magnetron sputtering PTFE and Al2...In order to improve the wear resistance of elastic metallic-plastic thrust bearing pad, micro-assembling PTFE/Al2O3 multi-layer film was developed by alternating radio frequency（RF） magnetron sputtering PTFE and Al2O3 targets. For enhancing the adhesion of the interfaces between PTFE and Al2O3 film, N+ implantation was employed. The structure, mechanical and micro-tribological properties were studied by XPS, X-ray photoelectron spectrometer and atomic force and friction force microscope （AFM/FFM）. The results show that the multi-layer consists of Al2O3 component and crystalline PTFE. The hardness of the multi-layer modified by ion implantation is less than that of Al2O3,but its toughness is greatly improved. The friction coefficient of PTFE/ Al2O3 multi-layer modified by ion implantation is much lower than that of Al2O3 film, and its resistance to wear is much greater than that of PTFE film. Therefore the wear resistance of elastic metallic-plastic thrust bearing pad is greatly improved.展开更多
The ineluctable introduction of lithium salt to polymer solid-state electrolytes incurs a compromise between strength,ionic conductivity,and thickness.Here,we propose Al_(2)O_(3)-coated polyimide(AO/PI)porous film as ...The ineluctable introduction of lithium salt to polymer solid-state electrolytes incurs a compromise between strength,ionic conductivity,and thickness.Here,we propose Al_(2)O_(3)-coated polyimide(AO/PI)porous film as a high-strength substrate to support fast-ion-conducting polymer-in-salt(PIS)solid-state electrolytes,aiming to suppress lithium dendrite growth and improve full-cell performance.The Al_(2)O_(3)coating layer not only refines the wettability of polyimide porous film to PIS,but also performs as a high modulus protective layer to suppress the growth of lithium dendrites.The resulting PI/AO@PIS exhibits a small thickness of only 35μm with an outstanding tensile strength of 11.3 MPa and Young's modulus of 537.6 MPa.In addition,the PI/AO@PIS delivers a high ionic conductivity of 0.1 m S/cm at 25°C.As a result,the PI/AO@PIS enables symmetric Li cells to achieve exceptional cyclability for over 1000 h at 0.1 m A/cm2without noticeable lithium dendrite formation.Moreover,the PI/AO@PIS-based LiFePO4||Li full cells demonstrate outstanding rate performance(125.7 m Ah/g at 5 C)and impressive cycling stability(96.1%capacity retention at 1 C after 200 cycles).This work highlights the efficacy of enhancing the mechanical properties of polymer matrices and extending cell performance through the incorporation of a dense inorganic interface layer.展开更多
A ternary system of PTFE/Al/Bi_(2)O_(3)is constructed by incorporating PTFE-based reactive material and thermite for enhancing the energy release of the PTFE-based reactive material.The effects of Bi_(2)O_(3)in the PT...A ternary system of PTFE/Al/Bi_(2)O_(3)is constructed by incorporating PTFE-based reactive material and thermite for enhancing the energy release of the PTFE-based reactive material.The effects of Bi_(2)O_(3)in the PTFE/Al/Bi_(2)O_(3)on both mechanical properties and the energy release were investigated through various tests such as thermogravimetry-differential scanning calorimetry,adiabatic oxygen bomb test and split Hopkinson pressure bar test.The microstructure observed through scanning electron microscope and Xray diffraction results are used to analyze the ignition and reaction mechanism of PTFE/Al/Bi_(2)O_(3).The results indicate that the PTFE/Al/Bi_(2)O_(3)are capable of triggering the exothermic reaction of molten PTFE/Bi_(2)O_(3)and Al/Bi_(2)O_(3)over the PTFE/Al reactive materials,thereby promoting reactions.The excessive aluminum in the ternary system is beneficial for increasing energy release.The ignition of shock-induced chemical reactions in PTFE/Al/Bi_(2)O_(3)is closely related to the material fracture.The dominant mechanism for hot-spot generation under Split Hopkinson Pressure Bar test is the frictional temperature rise at the microcrack after failure.展开更多
Preparation of Zr2Al3C4-Al2O3 in situ composites was investigated by self-propagating high-temperature synthesis(SHS)involving both aluminothermic reduction of ZrO2 and chemical activation of PTFE(Teflon).The starting...Preparation of Zr2Al3C4-Al2O3 in situ composites was investigated by self-propagating high-temperature synthesis(SHS)involving both aluminothermic reduction of ZrO2 and chemical activation of PTFE(Teflon).The starting materials included ZrO2,Al,carbon black and PTFE.In addition to the conventional SHS method,the experiments were conducted by a chemical-oven SHS(COSHS)route to thermally assist the synthesis reaction.The threshold amount of 2%(mass fraction)PTFE was required to induce self-sustaining combustion.When the conventional SHS scheme was utilized,due to low combustion temperatures between 1152 and 1272°C and insufficient reaction time,the dominant carbide forming in the composite was ZrC instead of Zr2Al3C4.On the other hand,the COSHS technique increased the combustion temperature of the reactant compact to about 1576°C,lengthened the high-temperature duration for the reaction,and prevented Al vapor from escaping away.As a consequence,Zr2Al3C4-Al2O3 composites with a small amount of Zr3Al3C5 were obtained.The microstructure of the COSHS-derived product showed that plate-like Zr2Al3C4 grains were about 2μm in thickness and 10-30μm in length,and most of them were closely stacked into a laminated configuration.展开更多
文摘高性能复合镀层具有优良的耐磨、耐蚀性能,能满足工业生产对材料性能的要求。研究了脉冲电沉积RE Ni W B PTFE Al2O3 复合镀层的成分、形貌及性能。结果表明:脉冲电流及Al2O3 固体颗粒能明显提高RE Ni W B PTFE Al2O3 复合镀层中W和B的含量;与直流电沉积相比,脉冲电沉积RE Ni W B复合镀层的表面裂纹已明显减小,但裂纹仍存在,当Al2O3 耐磨颗粒及PTFE减摩微粒嵌入RE Ni W B复合镀层中以后,在SEM 400倍下观察,RE Ni W B PTFE Al2O3镀层已不存在裂纹, 而且镀液中Al2O3 颗粒含量越多,晶粒就越细;此外,研究表明,镀液中Al2O3 颗粒含量增加, RE Ni W B PTFE Al2O3 复合镀层镀态硬度增加,磨损率降低。
文摘In order to improve the wear resistance of elastic metallic-plastic thrust bearing pad, micro-assembling PTFE/Al2O3 multi-layer film was developed by alternating radio frequency（RF） magnetron sputtering PTFE and Al2O3 targets. For enhancing the adhesion of the interfaces between PTFE and Al2O3 film, N+ implantation was employed. The structure, mechanical and micro-tribological properties were studied by XPS, X-ray photoelectron spectrometer and atomic force and friction force microscope （AFM/FFM）. The results show that the multi-layer consists of Al2O3 component and crystalline PTFE. The hardness of the multi-layer modified by ion implantation is less than that of Al2O3,but its toughness is greatly improved. The friction coefficient of PTFE/ Al2O3 multi-layer modified by ion implantation is much lower than that of Al2O3 film, and its resistance to wear is much greater than that of PTFE film. Therefore the wear resistance of elastic metallic-plastic thrust bearing pad is greatly improved.
基金the financial support from the 261Project of MIIT and Natural Science Foundation of Jiangsu Province(No.BK20240179)。
文摘The ineluctable introduction of lithium salt to polymer solid-state electrolytes incurs a compromise between strength,ionic conductivity,and thickness.Here,we propose Al_(2)O_(3)-coated polyimide(AO/PI)porous film as a high-strength substrate to support fast-ion-conducting polymer-in-salt(PIS)solid-state electrolytes,aiming to suppress lithium dendrite growth and improve full-cell performance.The Al_(2)O_(3)coating layer not only refines the wettability of polyimide porous film to PIS,but also performs as a high modulus protective layer to suppress the growth of lithium dendrites.The resulting PI/AO@PIS exhibits a small thickness of only 35μm with an outstanding tensile strength of 11.3 MPa and Young's modulus of 537.6 MPa.In addition,the PI/AO@PIS delivers a high ionic conductivity of 0.1 m S/cm at 25°C.As a result,the PI/AO@PIS enables symmetric Li cells to achieve exceptional cyclability for over 1000 h at 0.1 m A/cm2without noticeable lithium dendrite formation.Moreover,the PI/AO@PIS-based LiFePO4||Li full cells demonstrate outstanding rate performance(125.7 m Ah/g at 5 C)and impressive cycling stability(96.1%capacity retention at 1 C after 200 cycles).This work highlights the efficacy of enhancing the mechanical properties of polymer matrices and extending cell performance through the incorporation of a dense inorganic interface layer.
基金the National Natural Science Foundation of China (Grant No.12002045)State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology (Grant No.QNKT22-09)。
文摘A ternary system of PTFE/Al/Bi_(2)O_(3)is constructed by incorporating PTFE-based reactive material and thermite for enhancing the energy release of the PTFE-based reactive material.The effects of Bi_(2)O_(3)in the PTFE/Al/Bi_(2)O_(3)on both mechanical properties and the energy release were investigated through various tests such as thermogravimetry-differential scanning calorimetry,adiabatic oxygen bomb test and split Hopkinson pressure bar test.The microstructure observed through scanning electron microscope and Xray diffraction results are used to analyze the ignition and reaction mechanism of PTFE/Al/Bi_(2)O_(3).The results indicate that the PTFE/Al/Bi_(2)O_(3)are capable of triggering the exothermic reaction of molten PTFE/Bi_(2)O_(3)and Al/Bi_(2)O_(3)over the PTFE/Al reactive materials,thereby promoting reactions.The excessive aluminum in the ternary system is beneficial for increasing energy release.The ignition of shock-induced chemical reactions in PTFE/Al/Bi_(2)O_(3)is closely related to the material fracture.The dominant mechanism for hot-spot generation under Split Hopkinson Pressure Bar test is the frictional temperature rise at the microcrack after failure.
基金sponsored by the Ministry of Science and Technology of Taiwan,China,under the grant of MOST 105-2221-E-035-039-MY2
文摘Preparation of Zr2Al3C4-Al2O3 in situ composites was investigated by self-propagating high-temperature synthesis(SHS)involving both aluminothermic reduction of ZrO2 and chemical activation of PTFE(Teflon).The starting materials included ZrO2,Al,carbon black and PTFE.In addition to the conventional SHS method,the experiments were conducted by a chemical-oven SHS(COSHS)route to thermally assist the synthesis reaction.The threshold amount of 2%(mass fraction)PTFE was required to induce self-sustaining combustion.When the conventional SHS scheme was utilized,due to low combustion temperatures between 1152 and 1272°C and insufficient reaction time,the dominant carbide forming in the composite was ZrC instead of Zr2Al3C4.On the other hand,the COSHS technique increased the combustion temperature of the reactant compact to about 1576°C,lengthened the high-temperature duration for the reaction,and prevented Al vapor from escaping away.As a consequence,Zr2Al3C4-Al2O3 composites with a small amount of Zr3Al3C5 were obtained.The microstructure of the COSHS-derived product showed that plate-like Zr2Al3C4 grains were about 2μm in thickness and 10-30μm in length,and most of them were closely stacked into a laminated configuration.
