Crystal structure and microstructure of synthetic hexagonal magnesium–cobalt cordierite solid solutions (Mg_2−2xCo_2xAl₄Si₅O₁₈)

Magnesium–cobalt cordierites of hexagonal structure were synthesized by annealing glasses obtained from colloidal gel precursors and were investigated by means of X-ray powder diffraction and scanning electron microscopy. The formation of solid solutions with hexagonal structure (α-cordierite) in two concurrent crystallization paths, immediate crystallization or via phase transformation of intermediate μ-cordierite, was observed. The parameters of the crystalline structure and microstructure were extracted from X-ray diffraction patterns as mutually correlated in dependence on cobalt content.