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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°C、9.6h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°C、5.2h内只能放出7.91%的氢气。2LiBH4+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。
The formation conditions and mechanism of MgB2 in the process of desorption of 2LiBH4 + MgH2 were studied. The results show that the self-decomposition of LiBH4 in the 2LiBH4 + MgH2 system can be inhibited when hydrogen is released at higher initial pressure of 4.0 × 10 5 Pa, and then reacts with Mg generated by decomposition and desorption of MgH 2 to form MgB2. At the same time, ° C, 9.16% (mass fraction) of hydrogen was released in 9.6h; while at lower initial hydrogen pressure of 1.0 × 102Pa, LiBH4 decomposed spontaneously first and could not react with Mg to form MgB2 , At 450 ° C, only release 7.91% hydrogen within 5.2h. 2LiBH4 + MgH2 system to generate hydrogen into MgB2 hydrogenation reaction can be carried out more thoroughly, and release more hydrogen. The process of MgB2 formation during 2LiBH4 + MgH2 discharge is a process of inoculation and growth. With the increase of hydrogen back pressure, the incubation period is shortened. With the decrease of reaction temperature, the incubation period prolongs.