In this paper,the microstructure and hydrogen storage properties of the（NaH/Al）+x（molar fraction,%） Ti（x=0,4,6, 10） composites were investigated.It was found that the reversible hydrogen storage properties can b...In this paper,the microstructure and hydrogen storage properties of the（NaH/Al）+x（molar fraction,%） Ti（x=0,4,6, 10） composites were investigated.It was found that the reversible hydrogen storage properties can be improved by mechanically ball-milling the（NaH/Al） mixture together with Ti powder.H2 is a better ball-milling atmosphere than Ar,because a part of NaH is consumed during the ball-milling under an Ar atmosphere.As the Ti content increases,the hydrogen storage properties are enhanced gradually.In case of x=10,the reversible hydrogen absorption/desorption capacities of the composites milled for 6 h under the H2 atmosphere reach 4.01% and 3.93%（mass fraction）,respectively.The catalytic mechanism of the Ti-doped NaH/Al composites system is discussed briefly.展开更多
Mechanically activated disproportionation of Nd 12 Fe 82 B 6 alloy by ball milling in hydrogen atmosphere was experimentally investigated. The aspects of thermodynamics and kinetics for the mechanically activated disp...Mechanically activated disproportionation of Nd 12 Fe 82 B 6 alloy by ball milling in hydrogen atmosphere was experimentally investigated. The aspects of thermodynamics and kinetics for the mechanically activated disproportionation of the NdFeB alloy were discussed. Both the evolution of the disproportionation reaction and the corresponding microstructure change of the alloy during milling were characterized by X ray diffraction (XRD) analysis. The results show that the matrix phase Nd 2Fe 14 B of the as cast Nd 12 Fe 82 B 6 alloy can be disproportionated into a mixture of Nd hydride (H 5Nd 2), FeB/Fe 2B, and α Fe, by ball milling under hydrogen pressure of 0.2 MPa. The as disproportionated phases are of the size about 20 nm, suggesting that ball milling in hydrogen is an effective route for low temperature disproportionation processing of the NdFeB alloy to ensure a full nano structured as disproportionated microstructure. This is the basis for synthesizing Nd 2Fe 14 B/ α Fe nano composites with magnetic exchange coupling effect by subsequent desorption recombination processing.展开更多
文摘In this paper,the microstructure and hydrogen storage properties of the（NaH/Al）+x（molar fraction,%） Ti（x=0,4,6, 10） composites were investigated.It was found that the reversible hydrogen storage properties can be improved by mechanically ball-milling the（NaH/Al） mixture together with Ti powder.H2 is a better ball-milling atmosphere than Ar,because a part of NaH is consumed during the ball-milling under an Ar atmosphere.As the Ti content increases,the hydrogen storage properties are enhanced gradually.In case of x=10,the reversible hydrogen absorption/desorption capacities of the composites milled for 6 h under the H2 atmosphere reach 4.01% and 3.93%（mass fraction）,respectively.The catalytic mechanism of the Ti-doped NaH/Al composites system is discussed briefly.
文摘Mechanically activated disproportionation of Nd 12 Fe 82 B 6 alloy by ball milling in hydrogen atmosphere was experimentally investigated. The aspects of thermodynamics and kinetics for the mechanically activated disproportionation of the NdFeB alloy were discussed. Both the evolution of the disproportionation reaction and the corresponding microstructure change of the alloy during milling were characterized by X ray diffraction (XRD) analysis. The results show that the matrix phase Nd 2Fe 14 B of the as cast Nd 12 Fe 82 B 6 alloy can be disproportionated into a mixture of Nd hydride (H 5Nd 2), FeB/Fe 2B, and α Fe, by ball milling under hydrogen pressure of 0.2 MPa. The as disproportionated phases are of the size about 20 nm, suggesting that ball milling in hydrogen is an effective route for low temperature disproportionation processing of the NdFeB alloy to ensure a full nano structured as disproportionated microstructure. This is the basis for synthesizing Nd 2Fe 14 B/ α Fe nano composites with magnetic exchange coupling effect by subsequent desorption recombination processing.
