铝钎剂中活性剂的研究

本文指出长期以来,众多研究者一直提到的铝钎剂的活性剂是重金属氯化物的说法是不够确切的。实际上,大多数重金属氯化物不能作为活性剂。同时指出氯化物标准生成自由能判据,仅仅表明取代反应能否正向进行,而不能说明该氯化物是否可以作为活性剂。本研究提出:液态时与铝形成双液层的组元,或者液态时与铝能互相溶解,但在二元合金状态图的非铝端,形成熔点较低共晶物的组元,这些组元的氯化物,原则上可以作铝钎剂的活性剂。

Investigation of Active Agents in the Aluminum Brazing Fluxes

Many reserchers have so far proposed that the active agents ofaluminum brazing fluxes are chlorides of heavy metal elements, however,this proposal seems to be not precise. In fact, most of the heavy metal chlo-rides could not be used as active agents. Moreover, the criterion of free energyfor standard formation of chlorides may only show that a substitution reactionwill must be thermodynamically possible in positive direction; nevertheless, it can show that a chloride must be useful as an acgents. The investigationshows, if the components are capable of forming two--liquid layers withaluminum in liquid state, or they are miscible with aluminum in liquid andthe formed eutectics have lower melting points at the non--aluminum side ofthe binary phase diagrams, then the chlorides of these components couldprincipally be used as active agents of aluminum brazing fluxes.