The microstructure of a micro-defect-free (MDF) cement has been characterized by transmission electron microscopy (TEM), high-resolution electron microscopy (HREM) and energy-dispersive spectrometry (EDS). MDF cement consists of mono- and polycrystalline agglomerates of CaAl2O4 and CaAl4O7 grains randomly distributed in a polymer matrix. The agglomerates are surrounded by an amorphous layer of anhydrous product inside of which are distributed very fine crystllites of Ca2Al2O5·8H2O. This metastable pseudo-hexagonal crystalline hydration product is believed to be stabilized by the incorporation of organic chains in its basal interlayer. The polymer phase contains appreciable quantities of Al and Ca with Al/Ca = 4.3. This is explained in terms of preferential crosslinking ofpolymer with Al ions. Furthermore, this preferential Al crosslinking results in a Ca-rich interface, thereby favoring the formation of a calcium-rich hydration product.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics