Phase formation in the system (Ca,Sr)Al2O4
Barbier, Jacques; Neuhausen, Jörg
European Journal of Mineralogy Volume 2 Number 3 (1990), p. 273 - 282
published: Jun 21, 1990
manuscript accepted: Feb 14, 1990
manuscript received: Nov 28, 1989
ArtNo. ESP147050203004, Price: 29.00 €
Abstract The phase relations in the system (Ca,Sr)Al2O4 have been studied by powder X-ray diffraction and electron microscopy on products quenched from 1400 and 1600°C. Three structure-type have been identified including the CaAl2O4 beryUonite structure (0-30 at% Sr), a pseudo-hexagonal twinned orthorhombic structure (40-70 at% Sr). The quenched phases containing 40-100 at% Sr are room-temperature distortions of an unquenchable high-temperature hexagonal kalsilite phase. Strong structural analogies existing between the (Ca,Sr)Al2O4 and (Na,K)AlGeO4 systems are discussed in terms of the dependence of the topologies of the tetrahedral frameworks on the size of the alkali and alkaline-earth atoms.