A thermodynamic approach to the wetting and dewetting of grain boundaries

✍ Scribed by M.P. Brada; D.R. Clarke

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 885 KB
• Volume: 45
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/s1359-6454(96)00339-4

✦ Synopsis

An idealized geometry is adopted in order to calculate the equilibrium configuration of a constant volume of liquid initially partially wetting a grain boundary intersecting a free surface. To minimize the excess interfacial free energy, competition exists between the liquid as it dewets creating additional solid-solid interface (on the grain boundary) and increasing both the solid-liquid and liquid-vapor contact areas on the free surface. When the surface is flat only two possible non-trivial equilibrium configurations exist: either the liquid is all on the surface or it is all on the grain boundary. The transition between these two configurations is rather abrupt. The grain boundary wetting parameter kb plays a significant role in governing the equilibrium configuration, whereas the surface wetting parameter k, plays only a minor role. When the boundary intersects a deeply grooved surface, a third configuration is possible, one in which both the surface and the grain boundary are partially wetted. The implications of the calculations include the observed stability of remnant liquid phases in liquid phase sintered ceramics and the spontaneous wetting of metal grain boundaries by molten metals. such as gallium. 6 1997 Acta Metallurgica Inc.