LIQUID-PHASE SINTERING IN THE GLASS-CORDIERITE SYSTEM

Densification mechanisms and kinetics of liquid-phase sintering were studied using borosilicate glass-cordierite as a model system. It is shown that the sintering behaviour can be represented predominantly by a non-reactive liquid-phase sintering and that the densification is achieved mainly in the initial stage of sintering. From the activation energy estimates of densification, it is concluded that the predominant mechanism of densification is the viscous flow of glass with contribution arising from both viscous sintering of glass and glass redistribution kinetics. The latter evidence stems from the microstructural observation that as the sintering proceeds, the glass undergoes a time-dependent wetting behaviour. Based on this observation, and calculated infiltration times of melt into the porous compact, it is found that the time-dependent contact angle between the melt and the solid particles plays a significant role in the glass redistribution process.