电流作用下熔融金属在异种金属基板上的润湿性及界面化学

Recently, the electrowetting as a new technology to achieve the controllable wettability by using external electric current or electric field, has been widely applied to the displayer and vari-focal lens, and thus attracts many researchers' interests. Similarly, this technology can be applied to the metallurgical field to control the chemical properties of the solid/liquid interface, further to obtain reliable brazed joints or the preparation of good comprehensive performance composite. As the DC voltage and current to introduce not only can change the wettability of the system, but also can change the reactivity of the solid/liquid interface, the interfacial structure and spreading dynamics, so it is particularly important for research in this area. However, the factor of constraints for the current widely being used in the metallurgical field, the mechanism is still not very clear, and current as the introduction of external energy make the wetting mechanism, the driving force and interfacial chemical properties become more complex. This project was proposed by the three types of the driving forces in the high temperature as an entry point of the study: 1) The effect of current on the dissolution droved wetting and its mechanisms; 2) the effect of current on the interfacial reaction and spreading dynamics; 3) the effect of current on segregation of the chemical composition, surface or interface properties and spreading dynamics of mechanisms.

目前，依靠电流或电场来实现对液固介质润湿的可控，已广泛地应用于显示器件,可变焦透镜等领域，进而获得了极大的关注。同样，这种方式可应用于冶金领域来控制固/液界面的化学性质，从而获得可靠的钎焊接头或制备综合性能优良的复合材料。由于直流电压、电流的引入不但可以改变体系的润湿性，而且可以改变固/液界面的反应性质，界面结构及铺展动力学，因此对于这方面的研究显得尤为重要。然而，制约电流在冶金领域广泛应用的因素来自于其作用机制尚不十分明朗，电流作为外加能量的引入使得原本复杂的润湿机制，铺展驱动力及界面化学性质变得更加复杂。本项目以高温润湿中的三种驱动力作为出发点，研究：1）电流对溶解润湿的影响及其影响机制；2）电流对反应润湿中界面反应及铺展动力学的影响；3）电流对吸附润湿中化学成分偏聚的影响及由此引发的表界面性质及铺展动力学的影响机制。

电润湿在室温有机流体中已有了长足的应用与发展，然而在以金属熔体为研究对象的冶金过程中仍是急需解决的关键基础问题。在本项目中，以高温润湿体系中反应润湿，吸附润湿与溶解润湿为研究出发点，选取典型体系，研究了金属熔体分别在金属与陶瓷基板上的本征润湿行为。在金属/金属润湿体系中，基板表面的氧化膜是阻碍润湿进行的主要因素；在金属/陶瓷润湿体系中，固-液界面上的溶解，反应与吸附都可以成为润湿的驱动力。在此基础上，项目的开展以冷金属过渡焊接过程中的润湿现象为研究对象，研究了电弧和短路过渡电流作用下的润湿行为并提出了相应的润湿模型。以Wood合金为研究对象，不同电流电场作用下液态金属的变形机理及液态金属运动的驱动力，并建立了液态金属变形与电流电压参数的依赖关系。