Viscous sintering of non-spherical borosilicate-glass powder

Abstract

Densification by viscous flow - instead of diffusion - may be investigated by comparing densification rates and flow rates without the effect of external load, if possible. This is why the sintering of a borosilicate-glass powder was investigated using a hot-stage microscope. The samples sintered at 888 Κ showed shrinkage anisotropy, being the ratio of the axial to the radial shrinkage < 1. The flow rate varies linearly with the densification rate due to anisotropic densification; and the ratio between flow rate and densification rate may be altered by modifying the grade of anisotropy in densification. Scherer's theory has been used to compare experimental and theoretical values and the interdependence between densification rate and density. Deviations are discussed.