Au-30%Si合金熔体与石墨的润湿性及铺展动力学

Wettability and spreading dynamics of melting Au-30%Si alloys with graphite

采用改良座滴法在真空条件下研究Au-30%Si（摩尔分数）合金与石墨在1373-1473 K温度范围内的润湿性及铺展动力学。结果表明：随着温度升高,该体系润湿性得到改善,T=1373 K时,体系终态接触角高达100°,呈不润湿;当T≥1393 K时,随着温度的升高,接触角的变化速率明显加快,接触角减小至16°,呈现良好的润湿性。界面反应产物SiC的形成使得固/液界面能不断降低,为润湿铺展提供驱动力。通过建立新的反应润湿动力学模型,从能量角度阐述润湿铺展机制,预测体系固/液界面能随反应时间的延长呈指数关系降低。在反应控制阶段,理论计算与实验结果一致。

The wettability and spreading dynamics of Au-30%Si（mole fraction） alloys on graphite were studied using a modified sessile drop method under vacuum at 1373-1473 K. The results show that the wettability improves with the temperature increasing. The alloy is non-wetting with graphite and final contact angle as large as 100° at 1373 K. When T≥1393 K, the contact angle accelerates apparently with the temperature increasing, and finally presents an excellent wettability with contact angle decreasing to 16°. The formation of interfacial reaction products Si C resulting in the continuous decrease of solid-liquid interfacial energy, which provides the driving force for wetting and spreading. A spreading kinetic model is established, which explains the wetting mechanism from the angle of energy and predicts the solid-liquid interfacial energy decreasing with time in exponential relationship. The experimental results are in accord with the theoretical calculation in reaction-limited spreading.