Relation between Melting and Dehydrogenation Temperatures of LiAlH4
Relation between Melting and Dehydrogenation Temperatures of LiAlH4
复制标题
LiAlH4的熔化温度与脱氢温度的关系
DOI：
10.2320/matertrans.47.405
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发表时间：
2006
影响因子：
1.2
通讯作者：
T. Oishi
中科院分区：
文献类型：
--
作者：
H. Takeshita;Y. Kamada;A. Taniguchi;T. Kiyobayashi;K. Ichii;T. Oishi
采用差示扫描量热法（DSC）研究了lial4熔化对其脱氢性能的影响。对预先纯化的lialh4样品在不同加热条件下的脱氢行为进行了研究，其中一些加热条件是熔化的，另一些加热条件是不熔化的。一些接收到的样品在Ar气氛中使用球磨机进行短时间的机械研磨，然后提供给DSC测量。研磨后样品的颜色由灰褐色变为灰色，可能是由于研磨过程中淬硬钢容器和钢球中的铁和铬等金属元素污染所致。加热熔化后的样品氢的快速解吸，而未加热熔化后的样品尽管反复加热和冷却三次，但解吸效果不明显。lialh4从熔融到分解并伴有氢解吸的时间为90±30 s，与氢解吸温度无关。用行星型球磨机在淬硬钢容器中铣削的样品，其熔化温度比未提纯的样品低约2K，氢解吸温度比未提纯的样品低约15K。这些变化可以被认为是由于污染的金属元素有助于降低熔化温度，并作为催化剂降低液化lial4分解的活化能。这些结果表明，铁和铬等金属元素确实有助于提高丙酸盐的氢解吸温度，正如许多论文所报道的那样，但更重要的是降低它们的熔化温度，以提高它们的氢解吸动力学。
The effect of melting of LiAlH 4 on its dehydrogenation properties was examined using Differential Scanning Calorimetry (DSC). LiAlH 4 samples purified in advance were examined on their hydrogen desorption behaviors in the various heating conditions in which some of them were melted and the others not. Some of the as-received samples were mechanically ground in an Ar atmosphere for a short time of period using a ball milling machine and then supplied to DSC measurements. The color of the sample after milling changes from gray-beige to grey, probably due to contamination of metal elements such as iron and chromium from hardened steel vessel and balls during grinding. The rapid hydrogen desorption was observed for the samples melted by heating, whereas the insignificant hydrogen desorption was observed for the ones which were not melted by heating, in spite that heating and cooling were repeated three times. The time from melting to decomposition of LiAlH 4 accompanied by hydrogen desorption was 90 ± 30 s, independent of hydrogen desorption temperature. The samples milled in hardened steel vessel using a planetary-type ball milling machine exhibited about 2K lower melting temperature and 15K lower hydrogen desorption temperature than the as-purified samples. These changes can be considered to happen because contamination metal elements contributed to lowering a melting temperature and worked as a catalyst to decrease the activation energy for decomposition of liquefied LiAlH 4 . These results indicate that metal elements such as iron and chromium certainly contribute to improve hydrogen desorption temperatures of alanates, as reported in many papers, but it is more important to lower their melting temperatures in order to improve their hydrogen desorption kinetics.
影响因子：
3.3
作者：
Chen, J;Kuriyama, N;Sakai, T
通讯作者：
Sakai, T