Mo(Si,Al)_2的自蔓延高温燃烧合成

SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS OF Mo(Si,Al)-2

研究了Mo(Si,Al) 2 的自蔓延高温燃烧合成反应过程以及产物的生成机制。研究结果表明 :Al部分取代MoSi2 结构中的Si,不但对反应体系的热效应有影响 ,同时还对燃烧波前端的蔓延速度、反应体系的燃烧模式以及产物的结构有影响。这可以从Mo -Si-Al系自蔓延合成过程中反应体系的传质传热过程的改变得到较好的解释。Mo(Si,Al) 2 的自蔓延燃烧合成机制与MoSi2 相同 。

The process and the reaction mechanism of self-propagating high-temperature synthesis of Mo(Si,Al)-2 were investigated in the present work. The experimental results showed that the silicon in the MoSi-2 structure could be substituted partially by aluminum, which will influence not only on the calorific effect of the reaction system and the structure of the synthesized product, but also the combustion velocity of the propagating front and the combustion mode of the reactant compact. All the experimental phenomenon can be explained from the balance of heat during the combustion reaction and alternation of the heat and mass transfer mode. At the same time, the formation mechanism of Mo(Si,Al)-2 by SHS was studied. The experimental data indicated the formation of Mo(Si,Al)-2 from reactant elements occurs via a dissolution-precipitation process.