Ag-Cu-Ti活性钎料热力学分析

Thermodynamic analysis of a Ag-Cu-Ti active brazing alloy

在陶瓷与金属的活性钎焊连接技术中 ,Ag -Cu -Ti合金是研究和应用最多的钎料之一。合金组元Ti的活度是影响钎料 /陶瓷界面反应的关键因素 ,对钎料与陶瓷的润湿性和连接能力起着重要的作用。作者借助热力学对Ag -Cu -Ti活性钎料进行了热力学分析 ,重点分析了Ti的热力学活度及其与组分浓度之间的关系 ,计算了各组分之间的相互作用参数。分析和计算结果表明 ,Ti的活度随着Cu含量的增加而减小 ,随着Ag含量的增加而增大 ;Ag与Ti之间存在较大的排斥作用 ,两者的相互作用参数为 32 .83kJ/mol;而Cu与Ti之间存在强烈的吸引作用 ,其相互作用参数为 - 16 .14kJ/mol;Ag -Cu -Ti合金中添加某些与Cu的结合力大、与Ti的结合力小、且与合金组元不形成高熔点化合物或脆性相的合金元素 。

A Ag-Cu-Ti alloy is one of the most extensive brazing alloy for joining of ceramics to metals with active metal brazing method. The activity of Ti as a alloy element is a key factor influencing the interface reaction between ceramics and the brazing alloy, and plays an important role in wettability and joining ability of ceramics by the brazing alloy. In this paper, the Ag-Cu-Ti brazing alloy has been analyzed thermodynamically, the Ti activity and its relation to the concentration of the alloy components have been studied, and the interaction parameters of the alloy components have calculated. Results of the analysis and calculation have shown that the activity of Ti decreases with increasing Cu and decreasing Ag content. There is a certain repulsive interaction, 32.83 kJ/mol of calculated value, between Ag and Ti, while a strong attractive interaction, -16.14 kJ/mol, between Cu and Ti. In order to improving the activity of Ti, it is helpful to adding some alloy elements to the Ag-Cu-Ti alloy, which has a strong bond with Cu, a weak bond with Ti, and no formation of the high melting point compounds or brittle phases with alloy components.