Premium
Determining the Crystal Volume Fraction of BS 2 Glass by Differential Scanning Calorimetry and Optical Microscopy
Author(s) -
Silva Leidiane A.,
Mercury José M. R.,
Cabral Aluisio A.
Publication year - 2013
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12097
Subject(s) - differential scanning calorimetry , crystallization , orthorhombic crystal system , analytical chemistry (journal) , materials science , crystal (programming language) , optical microscope , volume fraction , scanning electron microscope , mineralogy , crystallography , chemistry , crystal structure , thermodynamics , composite material , chromatography , physics , organic chemistry , computer science , programming language
In this work, the crystal volume fraction, α( t ), of a barium disilicate ( BS 2 ) glass‐ceramic was carefully investigated by optical microscopy ( OM ) and differential scanning calorimetry ( DSC ). X‐ray diffraction experiment revealed that the reflected peaks of the glass‐ceramic, which was prepared by heat treatment at 1000°C for 12 h, were indexed as the low‐temperature orthorhombic sanbornite mineral phase. This result was confirmed by the refinement of the crystal structure parameters. Bulk samples were then heat‐treated in the range of 760°C to 830°C. In each case, the α( t ) values obtained by DSC were higher than those determined by OM due to surface crystallization and the formation of new nuclei during the heating/cooling steps in the DSC experiments. OM and DSC techniques were also used to estimate the number of preexisting nuclei, N q , in a set of samples heat‐treated at 790°C directly in the DSC furnace. At this temperature, it was found that the N q obtained directly by OM measurements were in reasonable agreement with those calculated from the combination of overall crystallization with crystal growth kinetics.