粗糙度对金属/金属非反应性润湿体系润湿性能的影响

Effect of roughness on wettability of metal/metal non-reactive wetting system

摘要:

本文采用真空座滴法研究了高温下基体粗糙度对金属/金属非反应性润湿体系润湿性能的影响,所选材料体系为AgCu28/Cu。发现粗糙度可显著促进该润湿体系的润湿性能,随着粗糙度的增加,润湿角逐渐减小,最后趋近于一个最小值,而润湿半径随粗糙度线性增加。当金属液体在粗糙表面润湿时,其润湿模型可分为基体表面的粘性流动和微观V型槽内的毛细流动两部分,两种模式下的润湿动力学均符合幂指数规律。基体表面液滴的润湿驱动力符合杨氏方程,在微观V型槽流动时会存在一种额外的毛细管力,使体系最终润湿角变小,从而获得更好的润湿性。

Abstract:

The effects of substrate roughness on wettability of non-reactive wetting and compound forming wetting systems are investigated by the sessile drop technique at high temperature. The AgCu28/copper system is selected in the presented study. It is found that the existence of roughness promotes wetting and spreading significantly. With the increase of roughness (R_a), the contact angle decreases sharply first and then approaches to a constant value, while the drop base radius increase linearly with R_a. Spreading of the liquid alloy on rough surface combined two modes: on top of the rough surface and inside the capillary grooves. The wetting kinetics for both modes follow the power law relationship. The driving force of flowing on the top of the rough surface follows the basic Young’s equation, while an additional driving force of capillary force exists when flow inside the micro v-grooves, leading to a decrease in final contact angle and consequently a better wettability.