Effects of high-energy ball milling on the microstructures of Si powders and consequently on the efficiency of Si-water reaction and the hydrogen generation behaviors are studied.During the milling process,both particle sizes and crystallite sizes of the powders decrease,but agglomerations,as well as the content of oxygen,internal strains,distortions and dislocations in the powders increase,and amorphous phase transformation of Si also appears on the particle surface.The increasing defects,including grain boundaries,internal strains,distortions and dislocations,amorphous phase transformation and powder refinement contribute to the hydrolysis performance of the powders.However,the growing contamination and agglomerations deteriorate the hydrolysis performance of the Si powders.The Si powders milled for 1 h have the best hydrolysis performances and produce 1 484.2 mL· g-1s at 70 ℃,whose hydrogen conversion rate reaches 94％.However,the residual ～6％(w/w) of Si is out of reaction primarily owing to the fact that the hydrolysis byproduct SiO2 adhering on the Si surface restrains the further reaction.%研究了高能球磨对Si粉微观结构和水解制氢性能的影响.球磨过程中,颗粒尺寸不断减小,非晶转变发生,晶界、内应力、位错以及晶格变形等微观缺陷不断增加,有利于提高Si粉的制氢性能;但随着球磨时间的延长,颗粒团聚趋于严重,粉末氧化不断加剧,降低了Si粉的制氢性能.当球磨时间为1 h,Si粉具有最优的制氢性能,70 ℃水解时其放氢量为1 484.2 mL·g-1s,但由于水解副产物SiO2包覆在Si表面导致其转化率为94％,无法继续完全水解.
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