Structural properties of amorphous Al2O3.2SiO 2 nanoparticles

Abstract

Structural properties of amorphous Al2O3.2SiO 2 (denoted as AS2) spherical nanoparticles have been studied in a model with different sizes of 2 nm, 3 nm and 4 nm under non-periodic boundary conditions with the BornMayer type pair potentials via molecular dynamics (MD) simulation. Structural properties were studied in details through the partial radial distribution functions (PRDF), coordination number distribution, bond-angle distributions and interatomic distances. Moreover, the radial density profiles in nanoparticles were also obtained. Calculations show that size effects on structure of a model are significant and calculated data differ from those obtained previously in the bulk one. We find that as the size larger than 3 nm, amorphous AS2 nanoparticle has a distorted tetrahedral network structure with the mean coordination number Z Al-O ≈ 4 and ZSi-O ≈ 4. The existence of triclusters in nanoparticles and size dependence of trie luster composition have been found and discussed. Furthermore, surface structure and surface energy of nanoparticles have been obtained and presented.