2Al 4Si 4O 16 (LiF-CaF 2-B 2O 3) glasses]]>

摘要

AbstractOn the basis of the mineral banalsit (BaNa2Al4Si4O16) and the addition of small B2O3concentrations, transparent glasses were prepared. Furthermore, in order to achieve nucleation, LiF and CaF2were added. Hexacelsian was formed in bulk crystallized glass samples whereas, monocelsian, as well as small quantities of nepheline and banalsite were crystallized from sintered glass powder. The scanning electron micrographs of the sintered samples show high crystallinity and crystals with sizes from nano to micrometers. The SEM micrographs and the EDX microanalyses show that nano size rods of monocelsian surrounded by micrometer-sized hexagonal nepheline, banalsite or residual glassy phase occur. The coefficient of thermal expansion of the samples sintered at 1000?°C was higher (12.93–9.52?×?10?6?K?1) in hexacelsian containing samples than in monocelsian (2.24–7.35?×?10?6?K?1) containing ones. The samples also showed notably different densities of 2.6424 and 2.4718?g/cm3, respectively.Graphical abstractDisplay OmittedHighlights?A glass based on banalsite mineral, within Na2O/BaO/Al2O3/SiO2system, was prepared with additional B2O3, CaF2and LiF.?Crystallization of bulk glasses gave hexacelsian while monocelsian in sintered powder with CaF2-and LiF-containing ones.?Micro- to nano– crystalline structure were obtained in the sintered samples.?In sintered samples high CTE was in hexacelsian contacting samples and low in monocelsian containing ones.]]>