Parasitic amorphous on single-domain crystal: structural observations of silicate glass-ceramics.

ABSTRACT: Glass-ceramics (GCs) are materials obtained from the crystallisation of functional phases in glass, and have a structure that the crystallised phase embedded in the glass matrix. Glass-forming oxides are commonly added to the functional phases to improve the stability of precursor glass; however, the issue of glass-ceramics permitting the presence of residual phases resulting from addition is required to be clarified. To elucidate this issue, we prepared 'perfectly surface-crystallised' GC consisting of fresnoite-type Sr(2)TiSi(2)O(8) from a non-stoichiometric glass and performed texture/morphology observations. Numerous SiO(2)-rich binodal-like nanospheres (~10 nm) were parasitic on the fresnoite single-crystal domains. The parasitic texture is considered to form via the following process: (i) binodal-type phase separation into stoichiometric fresnoite (crystalline matrix) and SiO(2)-rich phases (amorphous nanoparticles) and (ii) single-domain formation by surface crystallisation in the matrix. Furthermore, in terms of texture, the resulting GC differs from the GCs reported to date, i.e., inverse GC.

SUBMITTER: Takahashi Y 

PROVIDER: S-EPMC3556707 | biostudies-other | 2013

REPOSITORIES: biostudies-other