燃烧合成Mg2Ni储氢合金的热力学分析

Thermodynamic analysis of combustion synthesis of hydrogen storage alloy Mg_2Ni

从理论上对燃烧合成Mg2Ni反应体系在不同预热温度下的绝热温度及Mg2Ni的熔化率进行了计算.研究结果表明,反应的绝热温度随预热温度的升高而提高,而且二者的差值基本为一定值.在一定的预热温度下产物Mg2Ni将熔化,其熔化率随预热温度的升高或稀释剂含量的减少而增加.添加适量的稀释剂有助于降低反应的绝热温度、减小Mg2Ni的熔化分解从而得到高纯的Mg2Ni.

The adiabatic temperature ad~ and melting rate Rm of Mg2Ni in the combustion synthesis of the intermetallic phase Mg2Ni at different preheating temperatures were calculated theoretically. The results show that,with the preheating temperature increasing, the adiabatic temperature also increases and their difference is approximately a fixed value. When the preheating temperature exceeds a definite value, Mg2Ni begins to melt,and the higher the preheating temperature is or the less the amount of diluents is,the more the melting rate Rm of Mg2Ni is. Addtion of some moderate diluents is helpful to reduce the adiabatic temperature T.d and reduce the melt of Mg2Ni, so that a pure product can be obtained.