Abstract:
Wollastonite (CaSiO3) is an important mineral that is widely used in ceramics and polymer
industries. Defect energetics, diffusion of Ca ions and a solution of dopants are studied using
atomistic-scale simulation based on the classical pair potentials. The energetically favourable defect
process is calculated to be the Ca-Si anti-site defect cluster in which both Ca and Si swap their atomic
positions simultaneously. It is calculated that the Ca ion migrates in the ab plane with an activation
energy of 1.59 eV, inferring its slow diffusion. Favourable isovalent dopants on the Ca and Si sites
are Sr2+ and Ge4+, respectively. Subvalent doping by Al on the Si site is a favourable process to
incorporate additional Ca in the form of interstitials in CaSiO3. This engineering strategy would
increase the capacity of this material.
