With the aim to improve the strength of Al-Zn-Mg-Cu alloy,the alloy billet containing Mn was produced by spray forming method,and the microstructural features were investigated using X-ray diffraction（XRD）,optical m...With the aim to improve the strength of Al-Zn-Mg-Cu alloy,the alloy billet containing Mn was produced by spray forming method,and the microstructural features were investigated using X-ray diffraction（XRD）,optical microscopy（OM）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM） and differential scanning calorimetry（DSC）.The results show that the billet mainly consists of fine equiaxial grains of MgZn2 and Al6Mn with size ranging from 5 μm to 25 μm.Nano-scaled MgZn2 is dispersed in the as-sprayed alloy,primary Al6Mn particles are precipitated at grain boundaries with an average size of 5 μm.A few CuAl2,Al3Zr and eutectic are also found in as-sprayed Al alloy.The volume fraction of the porosity is about 12%.DSC result indicates that most of the solutes are precipitated during spray forming process,and no obviously thermal effects occur below 450 ℃.Both matrix grains and Al6Mn particles grow monotonously with the increase of annealing temperature,but the growth rate of Al6Mn particles is markedly lower than that of Al grains,and the matrix grains grow rapidly when the annealing temperature is above 375 ℃.展开更多
The P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were synthesized by an ultrasonic spray pyrolysis followed by solid-state sintering method.The structures,morphologies and electrochemical performances of Na_(2/3)Fe_...The P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were synthesized by an ultrasonic spray pyrolysis followed by solid-state sintering method.The structures,morphologies and electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were characterized thoroughly by means of X-ray diffractometer,scanning electron microscope and electrochemical charge/discharge instruments.Moreover,a thin layer of Al_(2)O_(3),which was formed on the surface of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2),can enhance the storage performance by preventing the formation of Na_(2)CO_(3)·H_(2)O,which is believed to enhance the electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials.This facile surface modification method may pave a way to synthesize advanced cathode materials for sodium-ion batteries.展开更多
基金Project(2006CB605204) supported by the National Basic Research Program of China
文摘With the aim to improve the strength of Al-Zn-Mg-Cu alloy,the alloy billet containing Mn was produced by spray forming method,and the microstructural features were investigated using X-ray diffraction（XRD）,optical microscopy（OM）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM） and differential scanning calorimetry（DSC）.The results show that the billet mainly consists of fine equiaxial grains of MgZn2 and Al6Mn with size ranging from 5 μm to 25 μm.Nano-scaled MgZn2 is dispersed in the as-sprayed alloy,primary Al6Mn particles are precipitated at grain boundaries with an average size of 5 μm.A few CuAl2,Al3Zr and eutectic are also found in as-sprayed Al alloy.The volume fraction of the porosity is about 12%.DSC result indicates that most of the solutes are precipitated during spray forming process,and no obviously thermal effects occur below 450 ℃.Both matrix grains and Al6Mn particles grow monotonously with the increase of annealing temperature,but the growth rate of Al6Mn particles is markedly lower than that of Al grains,and the matrix grains grow rapidly when the annealing temperature is above 375 ℃.
基金financially supported by the Natural Science Foundation of Hunan Province,China(No.2020JJ5755)the National Natural Science Foundation of China(Nos.51804344,51704332,51874360)the Innovation and Entrepreneurship Project of Hunan Province,China(No.2018GK5026)。
文摘The P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were synthesized by an ultrasonic spray pyrolysis followed by solid-state sintering method.The structures,morphologies and electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were characterized thoroughly by means of X-ray diffractometer,scanning electron microscope and electrochemical charge/discharge instruments.Moreover,a thin layer of Al_(2)O_(3),which was formed on the surface of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2),can enhance the storage performance by preventing the formation of Na_(2)CO_(3)·H_(2)O,which is believed to enhance the electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials.This facile surface modification method may pave a way to synthesize advanced cathode materials for sodium-ion batteries.
