Estimation of capillary pressure in liquid phase sintering

Abstract

The capillary force, arising from the curvature of the liquid meniscus between neighbouring particles in liquid phase sintering, provides a sintering driving force. The capillary force is orientated isotropically and provides a compressive stress normal to the neck section between neighbouring solid particles. During liquid phase sintering, the liquid accelerates mass transport and improves sintering densification owing to the intergrain capillary forces. This capillary force can be converted to an equivalent hydrostatic pressure. Based on the two particle model and Rayleigh distribution function of the closest distance between neighbour particles, the capillary pressure, also known as the sintering stress, was calculated in this study. As expected, when a compact with very low green density was sintered, the capillary pressure is small. The capillary pressure increases with densification but decreases when pores are closed up.