Microstructural development of a P2O5-modified cordierite glass ceramic during sintering Part 2. Densification experiments

Abstract

The non-isothermal sintering of a P2O5-modified cordierite glass powder was investigated using sintering dilatometry, DTA and x-ray diffractometry. A typical densification curve as obtained by dilatometry with a constant heating rate is discussed. To clarify the dependence of the final degree of porosity on the heating rate additional porosity measurements were carried out on selected specimens using a stereological image processing system. The porosity exhibits a distinct minimum for a heating rate of 15 K/min. This effect is discussed based on a variation of the effective sintering interval which ranges from Tg of the glass to the onset temperature of crystallization. Together with the crystallization behaviour, as given in part 1 of this paper, a schematic description of the microstructural development is presented.