CAJ | 학술논문

对2LiBH4+MgH2体系放氢过程中.MgB2的形成条件及机理进行研究.结果表明:在较高的4.0×105Pa初始氢背压下放氢时,会抑制2LiBH4+MgH2体系中LiBH4的自行分解,进而使其与MgH2分解放氢后生成的Mg发生反应生成MgB2,同时在450℃、9.6 h内释放出9.16%(质量分数)的氢气;而在较低的1.0×102Pa初始氢背压下放氢时,体系中LiBH4会先行发生自行分解,从而不能与Mg发生反应生成MgB2,在450 ℃、5.2 h内只能放出7.91%的氢气.2LiBH4十MgH2体系放氢生成MgB2可以使放氢反应进行得更彻底,并释放出更多的氢气.2LiBH4+MgH2放氢时MgB2的形成过程是一个孕育-长大的过程,随着氢背压的增高,孕育期缩短;而随着反应温度的降低,孕育期延长.
대2LiBH4+MgH2체계방경과정중.MgB2적형성조건급궤리진행연구.결과표명:재교고적4.0×105Pa초시경배압하방경시,회억제2LiBH4+MgH2체계중LiBH4적자행분해,진이사기여MgH2분해방경후생성적Mg발생반응생성MgB2,동시재450℃、9.6 h내석방출9.16%(질량분수)적경기;이재교저적1.0×102Pa초시경배압하방경시,체계중LiBH4회선행발생자행분해,종이불능여Mg발생반응생성MgB2,재450 ℃、5.2 h내지능방출7.91%적경기.2LiBH4십MgH2체계방경생성MgB2가이사방경반응진행득경철저,병석방출경다적경기.2LiBH4+MgH2방경시MgB2적형성과정시일개잉육-장대적과정,수착경배압적증고,잉육기축단;이수착반응온도적강저,잉육기연장.
The formation conditions of MgB2 in 2LiBH4 + MgH2 system during dehydrogenation were investigated and its mechanism was discussed. The results show that direct decomposition of LiBH4 is suppressed under relative higher initial dehydrogenation pressure of 4.0×105 Pa, wherein LiBH4, reacts with Mg to yield MgB2, and 9.16% (mass fraction) hydrogen is released within 9.6 h at 450 ℃. However, under relatively lower initial dehydrogenation pressure of 1.0×102Pa, LiBH4 decomposes independently instead of reacting with Mg, resulting in no formation of MgB2, and 7.91% hydrogen is desorbed within 5.2 h at 450 ℃. It is found that the dehydrogenation of 2LiBH4 + MgH2 system proceeds more completely and more hydrogen desorption amount can be obtained within a definite time by forming MgB2. Furthermore, it is proposed that the formation process of MgB2 includes incubation period and nucleus growth process. Experimental results show that the formation process of MgB2, especially the incubation period, is promoted by increasing initial dehydrogenation pressure at constant temperature, and the incubation period is also influenced greatly by dehydrogenation temperature.