氧化物催化劑對亞共晶Mg-Ni合金之儲放氫特性研究

Catalytic effects of oxide on hydrogen storage characteristic of hypoeutectic Mg-Ni alloy

高裕欽(Yu-chin Kao)

指導教授 ： 李勝隆

國立中央大學/工學院/機械工程學系/碩士(2008年)

摘要

本研究擬利用鑄造法製備亞共晶Mg-15 Ni合金，而後於球磨過程中將氧化物催化劑添加至亞共晶Mg-15Ni合金中，研究氧化物催化劑對亞共晶Mg-15Ni合金儲放氫特性之影響。
由X光繞射分析結果顯示，鑄態Mg-15Ni合金為Mg及Mg2Ni兩相所構成，經球磨後其繞射峰均有明顯寬化及弱化現象，而球磨中添加氧化物於Mg-15Ni合金中亦可觀察繞射峰均有明顯寬化及弱化的現象，此外也可發現微弱的氧化物繞射峰。在活化循環上，顯示添加氧化物不需長時間活化即有吸氫反應發生，以添加Cr2O3、Fe2O3效果較為明顯；在250、300 ℃儲放氫測試下，添加氧化物催化劑於Mg-15Ni合金中對吸放氫量及吸氫速率皆有所提升，然而在300 ℃下亦具有提高放氫速率與放氫比率之效果，但在250 ℃下的放氫速率仍有相當成效的效果，顯示於250 ℃下添加氧化劑並無法有效改善放氫速率。

關鍵字

儲氫合金 ； 亞共晶Mg-Ni合金 ； XRD ； 吸放氫速率

並列摘要

This research plans to utilize casting method to prepare hypoeutectic
Mg-15Ni alloy, and then adds the oxide catalysts in hypoeutectic Mg-15Ni alloy by ball milled, studies the oxide catalysts to influence on hydrogen storage characteristic of hypoeutectic Mg-15Ni alloy.
As-cast Mg-15Ni alloy is formed by Mg and Mg2Ni two phase by the
X-rays diffraction analysis, its diffraction peaks after the ball milled are obviously broaden and weaken , and adds oxides by ball milled can also observe diffraction peak it has to be obviously broadener and weakener than As-cast Mg-15Ni alloy , in addition can find the faint oxide diffraction peak. At activation circulation, reveals addition oxide catalyst can take place to react with hydrogen promptly without activation for a long time , and effect of Cr2O3, Fe2O3 is obviously outstanding; and during pressure-composite-isothermal test at 250,300 ℃, reveals addition the oxide catalyst enhances the absorption /desorption capacity and increases hydriding/dehydriding rate for Mg-15Ni alloy, however adding the oxide catalyst enhances desorption rate and desorption ratio at 300 ℃, but a little effect for enhancing desorption rate at 250 ℃,show that addition the oxide catalyst can not improve desorption rate effectively at 250 ℃ .

並列關鍵字

absorption/desorption rate ； hydrogen storage alloy ； hypoeutectic Mg-Ni alloy ； XRD

參考文獻

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