氣態(tài)儲氫性能
( 浙江大學 材料科學與工程學系， 杭州 310027)
摘 要: 納米晶Mg2-xTixNi0.8Cr0.2 (x=0.05, 0.10, 0.15, 0.20) 四元合金由純Mg, Ti, Ni, Cr粉在773K經(jīng)4h燒結(jié)后機械球磨而成。 該合金具有良好的活化性能和吸氫動力學性能。合金在393K, 4.0MPa氫壓條件下， 2min內(nèi)便可以完成總吸氫量的75%（質(zhì)量分數(shù)）以上， Mg1.95Ti0.05Ni0.8Cr0.2最大吸氫量可達到3.35%。 在493K， 0.1MPa條件下可快速放氫， Mg1.80Ti0.20Ni0.8Cr0.2在18min內(nèi)便可完成放氫過程， 總放氫量為2.17%。 所有合金具有良好的低溫吸氫性能， 353K時Mg1.85Ti0.15Ni0.8Cr0.2合金最大吸氫量可達到2.08%。 XRD分析結(jié)果顯示， Ti替代Mg后， 合金中主要存在Mg2Ni與Ni兩相， 另外， 還有微量的Mg與TiNi相， TiNi相彌散分布在合金中， 對合金的吸放氫性能有一定的催化作用。
關鍵字: 燒結(jié)； 球磨； 儲氫； Mg2Ni合金； 納米晶
tetragonal nanocrystalline
Mg2-xTixNi0.8Cr0.2 alloy
RONG Wei, CHEN Chang-pin
（ Department of Materials Science and Engineering,
Zhejiang University, Hangzhou 310027, China）
Abstract: Nanocrystalline Mg2-xTixNi0.8Cr0.2(x=0.05, 0.10, 0.15, 0.20) alloys were prepared by solid-sintering at 773K for 4h and subsequent ball milling. The as-milled alloys show good activation properties and hydrogen absorption kinetics. The nanocrystalline alloys finish more than 75%(mass fraction) of full hydrogen storage capacity in 2min at 393K under hydrogen pressure of 4.0MPa, and the maximum absorbed hydrogen content of nanocrystalline Mg1.95Ti0.05Ni0.8Cr0.2 alloy reaches 3.35%. The nanocrystalline alloys desorb H2 at 493K and under pressure of 0.1MPa rapidly. Mg1.80Ti0.20Ni0.8Cr0.2 alloy desorbs 2.17% H2 in 18min at 493K. In addition, the absorption kinetic of the nanocrystalline alloys is good at low temperatures. The full hydrogen storage of nanocrystalline Mg1.85Ti0.15Ni0.8Cr0.2 alloy reaches 2.08% at 353K. XRD analysis shows that the partial substitution of Ti for Mg results in the formation of Mg2Ni-Ni complex phase and precipitation single Mg and TiNi phase after milling, which improve mainly the absorption/desorption kinetics properties.
Key words: sintering; ball milling; hydrogen storage; Mg2Ni alloy; nanocrystalline
