Development of Chemical Vacuum Pump usingNitrogen Absorption Nano-Materials

本研究的目的是研制一种从大气压抽真空的轻便的“化学真空泵”。第一年，我们研究了用机械合金化的方法制备的锂基合金。对于Li-Fe合金，粉末能迅速吸收氮气。然而，由于Li被覆盖在铁粉表面的离子氧化物的还原反应消耗，因此吸收的气体的量是有限的。第二年，为了提高效率，用比锂氧化物更稳定的氧化物对锂进行了机械球磨。因此，添加氧化铝和氧化镁的球磨粉末与氮气反应非常活跃。尤其是锂铝合金能够吸收空气(氮气和氧气)，这是以前没有报道过的。去年，我们还调查了氮化物。在连的情况下，它也与氧气反应，表现出两个阶段的反应，远远高于与氮气的反应。其原因是α-LiS/1向β-Lian的相变和Li-O-N络合物的形成。

The purpose of this study is to develop a handy "Chemical Vacuum Pump" which evacuates from atmospheric pressure to vacuum. In the first year, the Li based alloys, which were produced by mechanical alloying with Si, Cu and Fe, were investigated. For the case of Li-Fe alloy, powders quickly absorb nitrogen gas. However, the amount of absorbed gas is limited, since Li is consumed by the reducing reaction with ion oxides covering the iron powder surface. In the second year, to improve the efficiency, the mechanical milling of Li with oxides which is more stable than lithium oxides were carried out. Thus, the powders milling with alumina and magnesia showed very active reactivity with nitrogen gas. Especially, Li-alumina alloy can absorb air (nitrogen and oxygen), which has not been reported before. In the last year, we also investigated nitrides. In the case of LiaN, it also reacts with oxygen gas showing two stage reactions, much higher than with nitrogen gas. The reason of this characteristic is attributable to the phase transition from alpha-Lis/1 to beta-LiaN and the formation of complex of Li-O-N.