In this paper, two types of comparison analyses, bulk analysis and defect analysis, were carried out for marine steel. The results of laser-induced breakdown spectroscopy （LIBS） were compared with those of spark opt...In this paper, two types of comparison analyses, bulk analysis and defect analysis, were carried out for marine steel. The results of laser-induced breakdown spectroscopy （LIBS） were compared with those of spark optical emission spectrometry （Spark-OES） and scanning electron microscopy/energy dispersion spectroscopy （SEM/EDS） in the bulk and defect analyses. The comparison of the bulk analyses shows that the chemical contents of C, Si, Mn, P, S and Cr obtained from LIBS agree well with those determined using Spark-OES. The LIBS is slightly less precise than Spark-OES. Defects were characterized in the two-dimensional distribution analysis mode for Al, Mg, Ca, Si and other elements. Both the LIBS and SEM/EDS results show the enrichment of Al, Mg, Ca and Si at the defect position and the two methods agree well with each other. SEM/EDS cannot provide information about the difference in the chemical constituents when the differences between the defect position and the normal position are not significant. However, LIBS can provide this information, meaning that the sensitivity of LIBS is higher than that of SEM/EDS. LIBS can be used to rapidly characterize marine steel defects and provide guidance for improving metallurgical processes.展开更多
Magnesium rechargeable batteries(MRBs)present opportunities for grid-scale energy storage applications as a complement to Li-ion batteries(LIBS).The major challenges are the low reversible capacity,inferior cycling st...Magnesium rechargeable batteries(MRBs)present opportunities for grid-scale energy storage applications as a complement to Li-ion batteries(LIBS).The major challenges are the low reversible capacity,inferior cycling stability and unsatisfactory energy densities.Na_(3)VCr_(0.5)Fe_(0.5)(PO_(4))_(3) with a well-defined NASIONtype structure is used as cathode in Mg cell.Two-electrons reaction(~116 m Ah/g),1.5 V average voltage and 65%of capacity retention over 100 cycles are accomplished.Mg is inserted by a biphasic reaction with the participation of V3+/V4+/V5+redox couples in the electrochemical reaction while the non-active redox couples such as Cr^(3+)/Cr^(4+)and Fe^(2+)/Fe^(3+)served as stabilizer to buffer the volume variation.A thermal stability up to~412℃ is also exhibited.Therefore,incorporating a mixture of three transition metal(V/Cr/Fe)in this type of structures will broaden new perspectives for realizing high performance cathodes for MRBs.展开更多
基金supported by a Special Fund for Nationally Important Instruments of China(No.2012YQ20018208)
文摘In this paper, two types of comparison analyses, bulk analysis and defect analysis, were carried out for marine steel. The results of laser-induced breakdown spectroscopy （LIBS） were compared with those of spark optical emission spectrometry （Spark-OES） and scanning electron microscopy/energy dispersion spectroscopy （SEM/EDS） in the bulk and defect analyses. The comparison of the bulk analyses shows that the chemical contents of C, Si, Mn, P, S and Cr obtained from LIBS agree well with those determined using Spark-OES. The LIBS is slightly less precise than Spark-OES. Defects were characterized in the two-dimensional distribution analysis mode for Al, Mg, Ca, Si and other elements. Both the LIBS and SEM/EDS results show the enrichment of Al, Mg, Ca and Si at the defect position and the two methods agree well with each other. SEM/EDS cannot provide information about the difference in the chemical constituents when the differences between the defect position and the normal position are not significant. However, LIBS can provide this information, meaning that the sensitivity of LIBS is higher than that of SEM/EDS. LIBS can be used to rapidly characterize marine steel defects and provide guidance for improving metallurgical processes.
基金supported by the Scientific Research Funds of Huaqiao University and Xiamen University Foreign Young Talents Program(No.G2022149004L)。
文摘Magnesium rechargeable batteries(MRBs)present opportunities for grid-scale energy storage applications as a complement to Li-ion batteries(LIBS).The major challenges are the low reversible capacity,inferior cycling stability and unsatisfactory energy densities.Na_(3)VCr_(0.5)Fe_(0.5)(PO_(4))_(3) with a well-defined NASIONtype structure is used as cathode in Mg cell.Two-electrons reaction(~116 m Ah/g),1.5 V average voltage and 65%of capacity retention over 100 cycles are accomplished.Mg is inserted by a biphasic reaction with the participation of V3+/V4+/V5+redox couples in the electrochemical reaction while the non-active redox couples such as Cr^(3+)/Cr^(4+)and Fe^(2+)/Fe^(3+)served as stabilizer to buffer the volume variation.A thermal stability up to~412℃ is also exhibited.Therefore,incorporating a mixture of three transition metal(V/Cr/Fe)in this type of structures will broaden new perspectives for realizing high performance cathodes for MRBs.
