Dicalcium silicates having CaO/SiO2 molar ratios of 1.8 to 2.2 were sintered at 1450°C for 90 min with or without small quantities of dopants (K2O or Al2O3) and were air quenched. The microstructures of the fired samples were characterized using electron microscopy (SEM and TEM) and associated microanalytical techniques. There was no evidence for the existence of Ca1.8SiO3.8 or Ca2.2SiO4.2. Amorphous grain‐boundary phases were observed between grains and as inclusions within the grains; the amounts decreased as CaO/SiO2 ratios increased. The compositions of the amorphous phases were always rich in dopants and had a CaO/SiO2 ratio close to that of wollastonite. High levels of Al2O3 were observed to enter the β‐Ca2SiO4 grains under lime‐rich conditions (CaO/SiO2= 2.2) up to a saturation level of about 3.0 wt%. Some additional crystalline phases were observed to form depending on stoichiometry and dopant level.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of the American Ceramic Society|
|State||Published - Sep 1988|
ASJC Scopus subject areas
- Ceramics and Composites
- Materials Chemistry