On the triple line in infiltration of liquid metals into porous preforms

Abstract

Two questions of current interest are addressed in this paper: (i) Are contact angles measured by means of the sessile drop technique of any help to understand liquid metal infiltration into solid porous preforms? (ii) To what extent are contact angles derived from either the capillary law or drainage curves valid? These questions have neither simple nor unique answers, as infiltration may occur under very different scenarios, i.e., non-reactive and reactive infiltration, both spontaneous and forced. However, while the use of the simplest version of the capillary law relies upon the questionable slug-flow hypothesis, analysing drainage curves by means of the Brooks and Corey model seems justified only for particular distributions of pore sizes such as a power law. However, experimental studies indicate that threshold pressures, and therefore contact angles, derived from those two methods are not very different.